Smart Power Grid
Encyclopedia
A smart grid is a digitally enabled electrical grid that gathers, distributes, and acts on information about the behavior of all participants (suppliers and consumers) in order to improve the efficiency, reliability, economics, and sustainability of electricity services.
Smart grid policy is organized in Europe as Smart Grids European Technology Platform. Policy in the United States is described in § 17381.
power grid evolved after 1896, based in part on Nikola Tesla
's design published in 1888 (see War of Currents
). Many implementation decisions that are still in use today were made for the first time using the limited emerging technology available 120 years ago. Specific obsolete power grid assumptions and features (like centralized unidirectional electric power transmission
, electricity distribution
, and demand-driven control) represent a vision of what was thought possible in the 19th century.
Part of this is due to an institutional risk aversion
that utilities naturally feel regarding use of untested technologies on a critical infrastructure
they have been charged with maintaining.
The 20th century power grids were originally built out as local grids which, over time, became interwoven for economic and reliability purposes. One of the largest engineered systems ever constructed, the mature, interconnected electric grid of the late 1960's became conceived of as "dividing and distributing" electric power, on a bulk basis, from a relatively small number (i.e., ~thousands) of "central plant" generating stations, to major load centers, and from there to a large number of individual consumers, large and small. The nature of generating technologies available over the first three-quarters of the 20th century lent themselves to both notable efficiencies of scale (individual plants of 1000-3000 MW were not uncommon) and to situationally-specific locations (hydroelectric plants at high dams, coal-, gas-, and oil-fired plants near supply lines, nuclear plants near supplies of cooling water, and all of them, for a variety of reasons, as far away from population centers as economically possible). As the electric power industry continued to produce ever more-affordable electric power to an ever-increasing base of customers, by the late 1960's it had reached nearly every home and business in the developed world. [references pending]
However, the data-collecting and processing capabilities of the era required broadly averaged, statistical rate classifications that severely limited the timely propagation of supply and demand price signals through the system. At the same time, increasing environmental concerns and increasing sociopolitical dependence on electrification combined to limit further economies of scale. By the end of the 20th century, the cost escalation of electric power in major metropolitan areas was considered untenable, and technologies that would remain recognizable to the founders of the industry from a century earlier were no longer considered adequate to an information- and services-based economy. [references pending]
Over the past 50 years, electricity networks have not kept pace with modern challenges, such as:
Although these points tend to be the "conventional wisdom" with respect to smart grids, their relative importance is debatable. For instance, despite the weaknesses of power network being publicly broadcast, there has never been an attack on a power network in the United States or Europe. However, in April 2009 it was learned that spies had infiltrated the power grids, perhaps as a means to attack the grid at a later time. In the case of renewable power and its variability, recent work undertaken in Europe (Dr. Bart Ummels et al.) suggests that a given power network can take up to 30% renewables (such as wind and solar) without any changes whatsoever.
Meanwhile, advances in automation, data communications, and distributed generation began to appear adequate to support the concept of a smart grid, which could accommodate suppliers and consumers from a wide range of circumstances, with a greater capacity to anticipate and respond to changing operating conditions, and with greater economic efficiency. [references pending]
The term smart grid has been in use since at least 2005, when the article "Toward A Smart Grid", authored by S. Massoud Amin and Bruce F. Wollenberg appeared in the September/October issue of IEEE P&E Magazine (Vol. 3, No.5, pgs 34–41). The term had been used previously and may date as far back as 1998. There are a great many smart grid definitions, some functional, some technological, and some benefits-oriented. A common element to most definitions is the application of digital processing and communications to the power grid, making data flow and information management central to the smart grid. Various capabilities result from the deeply integrated use of digital technology with power grids, and integration of the new grid information flows into utility processes and systems is one of the key issues in the design of smart grids. Electric utilities now find themselves making three classes of transformations: improvement of infrastructure, called the strong grid in China; addition of the digital layer, which is the essence of the smart grid; and business process transformation, necessary to capitalize on the investments in smart technology. Much of the modernization work that has been going on in electric grid modernization, especially substation and distribution automation, is now included in the general concept of the smart grid, but additional capabilities are evolving as well.
Smart grid technologies have emerged from earlier attempts at using electronic control, metering, and monitoring. In the 1980s, Automatic meter reading
was used for monitoring loads from large customers, and evolved into the Advanced Metering Infrastructure of the 1990s, whose meters could store how electricity was used at different times of the day. Smart meter
s add continuous communications so that monitoring can be done in real time, and can be used as a gateway to demand response
-aware devices and "smart sockets" in the home. Early forms of such Demand side management technologies were dynamic demand
aware devices that passively sensed the load on the grid by monitoring changes in the power supply frequency. Devices such as industrial and domestic air conditioners, refrigerators and heaters adjusted their duty cycle to avoid activation during times the grid was suffering a peak condition. Beginning in 2000, Italy's Telegestore Project was the first to network large numbers (27 million) of homes using such smart meters connected via low bandwidth power line communication
. Recent projects use Broadband over Power Line (BPL) communications, or wireless technologies such as mesh networking that is advocated as providing more reliable connections to disparate devices in the home as well as supporting metering of other utilities such as gas and water.
Monitoring and synchronization of wide area networks were revolutionized in the early 1990s when the Bonneville Power Administration
expanded its smart grid research with prototype sensors that are capable of very rapid analysis of anomalies in electricity quality over very large geographic areas. The culmination of this work was the first operational Wide Area Measurement System (WAMS) in 2000. Other countries are rapidly integrating this technology — China will have a comprehensive national WAMS system when its current 5-year economic plan is complete in 2012
In the US, the city of Austin, Texas
has been working on building its smart grid since 2003, when its utility first replaced 1/3 of its manual meters with smart meters that communicate via a wireless mesh network
. It currently manages 200,000 devices real-time (smart meters, smart thermostats, and sensors across its service area), and expects to be supporting 500,000 devices real-time in 2009 servicing 1 million consumers and 43,000 businesses. Boulder, Colorado
completed the first phase of its smart grid project in August 2008. Both systems use the smart meter as a gateway to the home automation
network (HAN) that controls smart sockets and devices. Some HAN designers favor decoupling control functions from the meter, out of concern of future mismatches with new standards and technologies available from the fast moving business segment of home electronic devices.
Hydro One
, in Ontario
, Canada is in the midst of a large-scale Smart Grid initiative, deploying a standards-compliant communications infrastructure from Trilliant. By the end of 2010, the system will serve 1.3 million customers in the province of Ontario. The initiative won the "Best AMR Initiative in North America" award from the Utility Planning Network.
The City of Mannheim
in Germany is using realtime Broadband Powerline (BPL) communications in its Model City Mannheim "MoMa" project
InovGrid is an innovative project in Evora
that aims to equip the electricity grid with information and devices to automate grid management, improve service quality, reduce operating costs, promote energy efficiency and environmental sustainability, and increase the penetration of renewable energies and electric vehicles.
It will be possible to control and manage the state of the entire electricity distribution grid at any given instant, allowing suppliers and energy services companies to use this technological platform to offer consumers information and added-value energy products and services.
This project to install an intelligent energy grid places Portugal and EDP at the cutting edge of technological innovation and service provision in Europe.
of the data flow is a major concern, with some early smart meter architectures allowing actually as long as 24 hours delay in receiving the data, preventing any possible reaction by either supplying or demanding devices.
and demand response
combined. Smart energy demand is what delivers the majority of smart meter and smart grid benefits.
Smart energy demand is a broad concept. It includes any energy-user actions to:
All of these actions minimize adverse impacts on electricity grids and maximize consumer savings.
Smart Energy Demand mechanisms and tactics include:
, see opportunity in providing devices to consumers very similar to those they have long been providing to industry. Others, such as Silver Spring Networks
or Google
, are data integrators rather than vendors of equipment. While the AC power control standards suggest powerline networking would be the primary means of communication among smart grid and home devices, the bits may not reach the home via Broadband over Power Lines (BPL) initially but by fixed wireless
. This may be only an interim solution, however, as separate power and data connections defeats full control.
, as well as earlier proposals (such as Al Gore
's continental Unified Smart Grid
) make semantic distinctions between local and national grids that sometimes conflict. Papers by Battaglini et al. associate the term "smart grid" with local clusters (page 6), whereas the intelligent interconnecting backbone provides an additional layer of coordination above the local smart grids. Media use in both Europe and the US however tends to conflate national and local.
Regardless of terminology used, smart grid projects always intend to allow the continental and national interconnection backbones to fail without causing local smart grids to fail. As in the case of existing utility infrastructure, they would have to be able to function independently and ration whatever power is available to critical needs.
Before recent standards efforts, municipal governments, for example in Miami, Florida
, have historically taken the lead in enforcing integration standards for smart grids/meters. As municipalities or municipal electricity monopolies also often own some fiber optic backbones and control transit exchanges at which communication service providers meet, they are often well positioned to force good integration.
Municipalities also have primary responsibility for emergency response and resilience
, and would in most cases have the legal mandate to ration or provision power, say to ensure that hospitals and fire response and shelters have priority and receive whatever power is still available in a general outage.
A home area network, or "home grid", extends some of these capabilities into the home using powerline networking and/or RF using standards such as ZigBee
, INSTEON
, Zwave, WiFi
or others. In the smart grid, NIST is promoting interoperability between the different standards. OSHAN is one initiative that enables interoperability in the home.
Because of the communication standards both smart power grids and some home area networks support more bandwidth than is required for power control and therefore may cost more than required. The existing 802.11 home networks generally have megabits of additional bandwidth for other services (burglary, fire, medical and environmental sensors and alarms, ULC and CCTV monitoring, access control and keying systems, intercoms and secure phone line services), and furthermore can't be separated from LAN
and VoIP networking, nor from TV once the IPTV
standards have emerged.
A number of companies have entered the home area network space, such as Plug Smart, a brand of Juice Technologies, LLC, Tendril, Control4, and EnergyHub.
Consumer electronics devices now consume over half the power in a typical US home. Accordingly, the ability to shut down or hibernate devices when they are not receiving data could be a major factor in cutting energy use, but this would mean the electric company has information on whether a consumer is using their computer or not.
Other key devices that could aide in the utilities efforts to shed load during times of peak demand include air conditioning units, electric water heaters, pool pumps and other high wattage devices.
In 2009, smart grid companies may represent one of the biggest and fastest growing sectors in the "cleantech" market. It consistently receives more than half the venture capital
investment.
In 2009 President Barack Obama
asked the United States Congress
"to act without delay" to pass legislation that included doubling alternative energy production in the next three years and building a new electricity "smart grid". On April 13, 2009, George W. Arnold was named the first National Coordinator for Smart Grid Interoperability.
or local distribution
tasks.
This paradigm is changing as businesses and homes begin generating more wind and solar electricity, enabling them to sell surplus energy back to their utilities. Modernization is necessary for energy consumption efficiency, real time management of power flows and to provide the bi-directional metering
needed to compensate local producers of power. Although transmission networks are already controlled in real time, many in the US and European countries are antiquated by world standards, and unable to handle modern challenges such as those posed by the intermittent nature of alternative electricity generation, or continental scale
bulk energy transmission.
and distribution grids. The modernization is directed at a disparate set of goals including facilitating greater competition between providers, enabling greater use of variable energy sources, establishing the automation and monitoring capabilities needed for bulk transmission at cross continent distances, and enabling the use of market forces to drive energy conservation.
Many smart grid features readily apparent to consumers such as smart meter
s serve the energy efficiency goal. The approach is to make it possible for energy suppliers to charge variable electric rates so that charges would reflect the large differences in cost of generating electricity during peak or off peak periods. Such capabilities allow load control switch
es to control large energy consuming devices such as hot water heaters so that they consume electricity when it is cheaper to produce.
.
According to proponents of smart grid plans, this will reduce the amount of spinning reserve that electric utilities have to keep on stand-by, as the load curve
will level itself through a combination of "invisible hand
" free-market capitalism and central control of a large number of devices by power management services that pay consumers a portion of the peak power saved by turning their devices off.
study calculated that internal modernization of US grids with smart grid capabilities would save between 46 and 117 billion dollars over the next 20 years. As well as these industrial modernization benefits, smart grid features could expand energy efficiency beyond the grid into the home by coordinating low priority home devices such as water heaters so that their use of power takes advantage of the most desirable energy sources. Smart grids can also coordinate the production of power from large numbers of small power producers such as owners of rooftop solar panels — an arrangement that would otherwise prove problematic for power systems operators at local utilities.
One important question is whether consumers will act in response to market signals. In the UK, where consumers have for nearly 10 years had a choice in the company from which they purchase electricity, more than 80% have stayed with their existing supplier, despite the fact that there are significant differences in the prices offered by a given electricity supplier.
Another concern is that the cost of telecommunications to fully support smart grids may be prohibitive. A less expensive communication mechanism is proposed using a form of "dynamic demand management
" where devices shave peaks by shifting their loads in reaction to grid frequency. Grid frequency could be used to communicate load information without the need of an additional telecommunication network, but it would not support economic bargaining or quantification of contributions.
Although there are specific and proven smart grid technologies in use, smart grid is an aggregate term for a set of related technologies on which a specification is generally agreed, rather than a name for a specific technology. Some of the benefits of such a modernized electricity network include the ability to reduce power consumption at the consumer side during peak hours, called demand side management; enabling grid connection
of distributed generation
power (with photovoltaic arrays, small wind turbine
s, micro hydro
, or even combined heat power generators in buildings); incorporating grid energy storage
for distributed generation load balancing; and eliminating or containing failures such as widespread power grid cascading failure
s. The increased efficiency and reliability of the smart grid is expected to save consumers money and help reduce emissions.
's Modern Grid Initiative report, a modern smart grid must:
As applied to distribution networks, there is no such thing as a "self healing" network. If there is a failure of an overhead power line, given that these tend to operate on a radial basis (for the most part) there is an inevitable loss of power. In the case of urban/city networks that for the most part are fed using underground cables, networks can be designed (through the use of interconnected topologies) such that failure of one part of the network will result in no loss of supply to end users. A fine example of an interconnected network using zoned protection is that of the Merseyside and North Wales Electricity Board (MANWEB
).
It is envisioned that the smart grid will likely have a control system that analyzes its performance using distributed, autonomous reinforcement learning
controllers that have learned successful strategies to govern the behavior of the grid in the face of an ever changing environment such as equipment failures. Such a system might be used to control electronic switches that are tied to multiple substations with varying costs of generation and reliability.
There is marketing evidence of consumer demand for greater choice. A survey conducted in the summer of 2007 interviewed almost 100 utility executives and sought the opinions of 1,900 households and small businesses from the U.S., Germany, Netherlands, England, Japan and Australia.
Among the findings:
And as already noted, in the UK where the experiment has been running longest, 80% have not changed their utility provider when given the choice (source: National Grid).
Proponents assert that the real-time, two-way communications available in a smart grid will enable consumers to be compensated for their efforts to save energy and to sell energy back to the grid through net-metering
. By enabling distributed generation resources like residential solar panels, small wind and plug-in hybrid, proponents assert that the smart grid will spark a revolution in the energy industry by allowing small players like individual homes and small businesses to sell power to their neighbors or back to the grid. Many utilities currently promote small independent distributed generation and successfully integrate it with no impact. These sources of power are currently cost-effective with the help government subsidies that are available to help consumers purchase the often expensive equipment that is required.
The same will hold true for larger commercial businesses that have renewable or back-up power systems that can provide power for a price during peak demand events, typically in the summer when air condition units place a strain on the grid. This participation by smaller entities has been called the "democratization of energy"—it is similar to former Vice President Al Gore
's vision for a Unified Smart Grid
.
One of the most important issues of resist attack is the smart monitoring of power grids, which is the basis of control and management of smart grids to avoid or mitigate the system-wide disruptions like blackouts. The traditional monitoring is based on weighted least square (WLS) which is very weak and prone to fail when gross errors (including topology errors, measurement errors or parameter errors) are present. New technology of state monitor is needed to achieve the goals of the smart grids.
Intelligence in distribution grids are not required to enable small producers to generate and sell electricity at the local level using alternative sources such as rooftop-mounted photo voltaic panels, small-scale wind turbines, and micro hydro generators. For example Chelan PUD's SNAP program promotes distributed, consumer owned small scale generation. Only after very high penetration of these types of resources is additional intelligence provided by sensors and software designed to react instantaneously to imbalances caused by intermittent sources, such as distributed generation, necessary.
support allows generators and loads to interact in an automated fashion in real time, coordinating demand to flatten spikes. Eliminating the fraction of demand that occurs in these spikes eliminates the cost of adding reserve generators, cuts wear and tear
and extends the life of equipment, and allows users to cut their energy bills by telling low priority devices to use energy only when it is cheapest.
Currently, power grid systems have varying degrees of communication within control systems for their high value assets, such as in generating plants, transmission lines, substations and major energy users. In general information flows one way, from the users and the loads they control back to the utilities. The utilities attempt to meet the demand and succeed or fail to varying degrees (brownout, rolling blackout, uncontrolled blackout). The total amount of power demand by the users can have a very wide probability distribution
which requires spare generating plants in standby mode to respond to the rapidly changing power usage. This one-way flow of information is expensive; the last 10% of generating capacity may be required as little as 1% of the time, and brownouts and outages can be costly to consumers.
. See power outage
. A technique to prevent this is load shedding by rolling blackout
or voltage reduction (brownout).
allows individual consumers to generate power onsite, using whatever generation method they find appropriate. This allows individual loads to tailor their generation directly to their load, making them independent from grid power failures. Classic grids were designed for one-way flow of electricity, but if a local sub-network generates more power than it is consuming, the reverse flow can raise safety and reliability issues. A smart grid can manage these situations, but utilities routinely manage this type of situation in the existing grid.
s in many homes to encourage people to use their electric power during night time or weekends, when the overall demand from industry is very low. During off-peak time the price is reduced significantly, primarily for heating storage radiators or heat pumps with a high thermal mass, but also for domestic appliances. This idea will be further explored in a smart grid, where the price could be changing in seconds and electric equipment is given methods to react on that.
), energy management systems, wireless mesh networks and other technologies, power-line carrier communications, and fiber-optics. Integrated communications will allow for real-time control, information and data exchange to optimize system reliability, asset utilization, and security.
) and meter reading equipment, wide-area monitoring systems, dynamic line rating (typically based on online readings by Distributed temperature sensing
combined with Real time thermal rating (RTTR) systems), electromagnetic signature measurement/analysis, time-of-use and real-time pricing tools, advanced switches and cables, backscatter radio technology, and Digital protective relay
s.
satellites could be used for very precise time measurements in the grid. With large numbers of PMUs and the ability to compare shapes from alternating current readings everywhere on the grid, research suggests that automated systems will be able to revolutionize the management of power systems by responding to system conditions in a rapid, dynamic fashion.
A wide-area measurement system (WAMS) is a network of PMUS that can provide real-time monitoring on a regional and national scale. Many in the power systems engineering community believe that the Northeast blackout of 2003
would have been contained to a much smaller area if a wide area phasor measurement network was in place.
, fault tolerance, storage, power electronics, and diagnostics components are changing fundamental abilities and characteristics of grids. Technologies within these broad R&D categories include: flexible alternating current transmission system devices, high voltage direct current, first and second generation superconducting wire, high temperature superconducting cable, distributed energy generation and storage devices, composite conductors, and “intelligent” appliances.
enables rapid diagnosis of and precise solutions to specific grid disruptions or outages. These technologies rely on and contribute to each of the other four key areas. Three technology categories for advanced control methods are: distributed intelligent agents (control systems), analytical tools (software algorithms and high-speed computers), and operational applications (SCADA, substation automation, demand response, etc.). Using artificial intelligence
programming techniques, Fujian
power grid in China created a wide area protection system that is rapidly able to accurately calculate a control strategy and execute it. The Voltage Stability Monitoring & Control (VSMC) software uses a sensitivity-based successive linear programming
method to reliably determine the optimal control solution.
MultiSpeak has created a specification that supports distribution functionality of the smart grid. MultiSpeak has a robust set of integration definitions that supports nearly all of the software interfaces necessary for a distribution utility or for the distribution portion of a vertically integrated utility. MultiSpeak integration is defined using extensible markup language (XML) and web services.
The IEEE has created a standard to support synchrophasors – C37.118.
The UCA International User Group discusses and supports real world experience of the standards used in smart grids.
A utility task group within LonMark International deals with smart grid related issues.
There is a growing trend towards the use of TCP/IP technology as a common communication platform for smart meter applications, so that utilities can deploy multiple communication systems, while using IP technology as a common management platform.
IEEE P2030
is an IEEE project developing a "Draft Guide for Smart Grid Interoperability of Energy Technology and Information Technology Operation with the Electric Power System (EPS), and End-Use Applications and Loads".
NIST has included ITU-T
G.hn
as one of the "Standards Identified for Implementation" for the Smart Grid "for which it believed there
was strong stakeholder consensus". G.hn is standard for high-speed communications over power lines, phone lines and coaxial cables.
OASIS EnergyInterop' – is an OASIS technical committee developing XML standards for energy interoperation. It's starting point is the California OpenADR standard.
Under the Energy Independence and Security Act of 2007 (EISA), NIST is charged with overseeing the identification and selection of hundreds of standards that will be required to implement the Smart Grid in the U.S. These standards will be referred by NIST to the Federal Energy Regulatory Commission
(FERC). This work has begun, and the first standards have already been selected for inclusion in NIST’s Smart Grid catalog. However, some commentators have suggested that the benefits that could be realized from Smart Grid standardization could be threatened by a growing number of patents that cover Smart Grid architecture and technologies. If patents that cover standardized Smart Grid elements are not revealed until technology is broadly distributed throughout the network (“locked-in”), significant disruption could occur when patent holders seek to collect unanticipated rents from large segments of the market.
with demand using multiple identical generators which can start, stop and operate efficiently at chosen load, independently of the others, making them suitable for base load
and peaking
power generation. Matching supply and demand, called load balancing
, is essential for a stable and reliable supply of electricity. Short-term deviations in the balance lead to frequency variations and a prolonged mismatch results in blackouts
. Operators of power transmission systems
are charged with the balancing task, matching the power output of the all the generators
to the load of their electrical grid. The load balancing task has become much more challenging as increasingly intermittent and variable generators such as wind turbines
and solar cells
are added to the grid, forcing other producers to adapt their output much more frequently than has been required in the past.
First two dynamic grid stability power plants utilizing the concept has been ordered by Elering
and will be built by Wärtsilä
in Kiisa
, Estonia
. Their purpose is to "provide dynamic generation capacity to meet sudden and unexpected drops in the electricity supply." They are scheduled to be ready during 2013 and 2014, and their total output will be 250 MW.
. In a recent brainstorming session, the power grid was considered within the context of optimal control
, ecology
, human cognition, glassy dynamics, information theory
, microphysics of clouds, and many others. Here is a selection of the types of analyses that have appeared in recent years.
Protection systems that verify and supervise themselves
Pelqim Spahiu and Ian R. Evans in their study introduced the concept of a substation based smart protection and hybrid Inspection Unit.
Kuramoto oscillators
The Kuramoto model
is a well-studied system. The power grid has been described in this context as well. The goal is to keep the system in balance, and/or to maintain phase synchronization
(also known as phase locking). Non-uniform oscillators also help to model different technologies, different types of power generators, patterns of consumption, and so on. The model has also been used to describe the synchronization patterns in the blinking of fireflies.
Bio-systems
Power grids have been related to complex biological systems in many other contexts. In one study, power grids were compared to the dolphin
social network. These creatures streamline and/or intensify communication in case of an unusual situation. The intercommunications that enable them to survive are highly complex.
Random fuse networks
In percolation theory
, random fuse
networks have been studied. The current density
might be too low in some areas, and too strong in others. The analysis can therefore be used to smooth out potential problems in the network. For instance, high-speed computer analysis can predict blown fuses and correct for them, or analyze patterns that might lead to a power outage. It is difficult for humans to predict the long term patterns in complex networks, so fuse and/or diode networks are used instead.
Neural networks
Neural network
s have been considered for power grid management as well. The references are too numerous to list.
Markov processes
As wind power
continues to gain popularity, it becomes a necessary ingredient in realistic power grid studies. Off-line storage, wind variability, supply, demand, pricing, and other factors can be modelled as a mathematical game. Here the goal is to develop a winning strategy. Markov process
es have been used to model and study this type of system.
Maximum entropy
All of these methods are, in one way or another, maximum entropy methods, which is an active area of research. This goes back to the ideas of Shannon, and many other researchers who studied communication networks. Continuing along similar lines today, modern wireless network research often considers the problem of network congestion, and many algorithms are being proposed to minimize it, including game theory, innovative combinations of FDMA, TDMA
, and others.
Before a utility installs an advanced metering system, or any type of smart system
, it must make a business case for the investment. Some components, like the power system stabilizers (PSS) installed on generators are very expensive, require complex integration in the grid's control system, are needed only during emergencies, but are only effective if other suppliers on the network have them. Without any incentive to install them, power suppliers don't. Most utilities find it difficult to justify installing a communications infrastructure for a single application (e.g. meter reading). Because of this, a utility must typically identify several applications that will use the same communications infrastructure – for example, reading a meter, monitoring power quality, remote connection and disconnection of customers, enabling demand response, etc. Ideally, the communications infrastructure will not only support near-term applications, but unanticipated applications that will arise in the future. Regulatory or legislative actions can also drive utilities to implement pieces of a smart grid puzzle. Each utility has a unique set of business, regulatory, and legislative drivers that guide its investments. This means that each utility will take a different path to creating their smart grid and that different utilities will create smart grids at different adoption rates.
Some features of smart grids draw opposition from industries that currently are, or hope to provide similar services. An example is competition with cable and DSL Internet providers from broadband over powerline internet access
. Providers of SCADA control systems for grids have intentionally designed proprietary hardware, protocols and software so that they cannot inter-operate with other systems in order to tie its customers to the vendor.
A technology competition identified this model regions to carry out research and development activities with the main objective to create an "Internet of Energy"
One of the first attempted deployments of "smart grid" technologies in the United States
was rejected in 2009 by electricity regulators
in the Commonwealth of Massachusetts, a US state. According to an article in the Boston Globe, Northeast Utilities' Western Massachusetts Electric Co. subsidiary actually attempted to create a "smart grid" program using public subsidies that would switch low income
customers from post-pay to pre-pay billing (using "smart card
s") in addition to special hiked "premium" rates for electricity used above a predetermined amount. This plan was rejected by regulators as it "eroded important protections
for low-income
customers against shutoffs". According to the Boston Globe, the plan "unfairly targeted
low-income customers and circumvented Massachusetts laws meant to help struggling consumers
keep the lights on". A spokesman for an environmental group
supportive of smart grid plans and Western Massachusetts' Electric's aforementioned "smart grid" plan, in particular, stated "If used properly, smart grid technology has a lot of potential for reducing peak demand, which would allow us to shut down some of the oldest, dirtiest power plants... It’s a tool."
In the Netherlands a large scale project (>5000 connections, >20 partners) was initiated to demonstrate integrated smart grids technologies, services and business cases.
A smart grid precisely limits electrical power down to the residential level, network small-scale distributed energy generation and storage devices, communicate information on operating status and needs, collect information on prices and grid conditions, and move the grid beyond central control to a collaborative network.
group expects to deliver early 2011 an overarching set of guidelines on smart grid interfaces. The new guidelines will cover areas including batteries and supercapacitor
s as well as flywheel
s. the group has also spun out a 2030.1 effort drafting guidelines for integrating electric vehicle
s into the smart grid.
Smart grid policy is organized in Europe as Smart Grids European Technology Platform. Policy in the United States is described in § 17381.
Background and goals
The smart grid implies a fundamental re-engineering of the electricity services industry, but focuses on the technical infrastructure.History
Today's alternating currentAlternating current
In alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
power grid evolved after 1896, based in part on Nikola Tesla
Nikola Tesla
Nikola Tesla was a Serbian-American inventor, mechanical engineer, and electrical engineer...
's design published in 1888 (see War of Currents
War of Currents
In the "War of Currents" era in the late 1880s, George Westinghouse and Thomas Edison became adversaries due to Edison's promotion of direct current for electric power distribution over alternating current advocated by several European companies and Westinghouse Electric based out of Pittsburgh,...
). Many implementation decisions that are still in use today were made for the first time using the limited emerging technology available 120 years ago. Specific obsolete power grid assumptions and features (like centralized unidirectional electric power transmission
Electric power transmission
Electric-power transmission is the bulk transfer of electrical energy, from generating power plants to Electrical substations located near demand centers...
, electricity distribution
Electricity distribution
File:Electricity grid simple- North America.svg|thumb|380px|right|Simplified diagram of AC electricity distribution from generation stations to consumers...
, and demand-driven control) represent a vision of what was thought possible in the 19th century.
Part of this is due to an institutional risk aversion
Risk aversion
Risk aversion is a concept in psychology, economics, and finance, based on the behavior of humans while exposed to uncertainty....
that utilities naturally feel regarding use of untested technologies on a critical infrastructure
Critical infrastructure
Critical infrastructure is a term used by governments to describe assets that are essential for the functioning of a society and economy. Most commonly associated with the term are facilities for:*electricity generation, transmission and distribution;...
they have been charged with maintaining.
The 20th century power grids were originally built out as local grids which, over time, became interwoven for economic and reliability purposes. One of the largest engineered systems ever constructed, the mature, interconnected electric grid of the late 1960's became conceived of as "dividing and distributing" electric power, on a bulk basis, from a relatively small number (i.e., ~thousands) of "central plant" generating stations, to major load centers, and from there to a large number of individual consumers, large and small. The nature of generating technologies available over the first three-quarters of the 20th century lent themselves to both notable efficiencies of scale (individual plants of 1000-3000 MW were not uncommon) and to situationally-specific locations (hydroelectric plants at high dams, coal-, gas-, and oil-fired plants near supply lines, nuclear plants near supplies of cooling water, and all of them, for a variety of reasons, as far away from population centers as economically possible). As the electric power industry continued to produce ever more-affordable electric power to an ever-increasing base of customers, by the late 1960's it had reached nearly every home and business in the developed world. [references pending]
However, the data-collecting and processing capabilities of the era required broadly averaged, statistical rate classifications that severely limited the timely propagation of supply and demand price signals through the system. At the same time, increasing environmental concerns and increasing sociopolitical dependence on electrification combined to limit further economies of scale. By the end of the 20th century, the cost escalation of electric power in major metropolitan areas was considered untenable, and technologies that would remain recognizable to the founders of the industry from a century earlier were no longer considered adequate to an information- and services-based economy. [references pending]
Over the past 50 years, electricity networks have not kept pace with modern challenges, such as:
- security threats, from either energy suppliers or cyber attack
- national goals to employ alternative power generation sources whose intermittent supply makes maintaining stable power significantly more complex
- conservation goals that seek to lessen peak demand surges during the day so that less energy is wasted in order to ensure adequate reserves
- high demand for an electricity supply that is uninterruptible
- digitally controlled devices that can alter the nature of the electrical load (giving the electric company the ability to turn off appliances in your home if they see fit) and result in electricity demand that is incompatible with a power system that was built to serve an “analog economy.” For a simple example, timed Christmas lights can present significant surges in demand because they come on at near the same time (sundown or a set time). Without the kind of coordination that a smart grid can provide, the increased use of such devices lead to electric service reliability problems, power qualityPower qualityPower quality is the set of limits of electrical properties that allows electrical systems to function in their intended manner without significant loss of performance or life. The term is used to describe electric power that drives an electrical load and the load's ability to function properly...
disturbances, blackoutsPower outageA power outage is a short- or long-term loss of the electric power to an area.There are many causes of power failures in an electricity network...
, and brownoutsBrownout (electricity)A brownout is an intentional drop in voltage in an electrical power supply system used for load reduction in an emergency. The reduction lasts for minutes or hours, as opposed to short-term voltage sag or dip. The term brownout comes from the dimming experienced by lighting when the voltage sags...
.
Although these points tend to be the "conventional wisdom" with respect to smart grids, their relative importance is debatable. For instance, despite the weaknesses of power network being publicly broadcast, there has never been an attack on a power network in the United States or Europe. However, in April 2009 it was learned that spies had infiltrated the power grids, perhaps as a means to attack the grid at a later time. In the case of renewable power and its variability, recent work undertaken in Europe (Dr. Bart Ummels et al.) suggests that a given power network can take up to 30% renewables (such as wind and solar) without any changes whatsoever.
Meanwhile, advances in automation, data communications, and distributed generation began to appear adequate to support the concept of a smart grid, which could accommodate suppliers and consumers from a wide range of circumstances, with a greater capacity to anticipate and respond to changing operating conditions, and with greater economic efficiency. [references pending]
The term smart grid has been in use since at least 2005, when the article "Toward A Smart Grid", authored by S. Massoud Amin and Bruce F. Wollenberg appeared in the September/October issue of IEEE P&E Magazine (Vol. 3, No.5, pgs 34–41). The term had been used previously and may date as far back as 1998. There are a great many smart grid definitions, some functional, some technological, and some benefits-oriented. A common element to most definitions is the application of digital processing and communications to the power grid, making data flow and information management central to the smart grid. Various capabilities result from the deeply integrated use of digital technology with power grids, and integration of the new grid information flows into utility processes and systems is one of the key issues in the design of smart grids. Electric utilities now find themselves making three classes of transformations: improvement of infrastructure, called the strong grid in China; addition of the digital layer, which is the essence of the smart grid; and business process transformation, necessary to capitalize on the investments in smart technology. Much of the modernization work that has been going on in electric grid modernization, especially substation and distribution automation, is now included in the general concept of the smart grid, but additional capabilities are evolving as well.
Smart grid technologies have emerged from earlier attempts at using electronic control, metering, and monitoring. In the 1980s, Automatic meter reading
Automatic meter reading
Automatic meter reading, or AMR, is the technology of automatically collecting consumption, diagnostic, and status data from water meter or energy metering devices and transferring that data to a central database for billing, troubleshooting, and analyzing.This technology mainly saves utility...
was used for monitoring loads from large customers, and evolved into the Advanced Metering Infrastructure of the 1990s, whose meters could store how electricity was used at different times of the day. Smart meter
Smart meter
A smart meter is usually an electrical meter that records consumption of electric energy in intervals of an hour or less and communicates that information at least daily back to the utility for monitoring and billing purposes. Smart meters enable two-way communication between the meter and the...
s add continuous communications so that monitoring can be done in real time, and can be used as a gateway to demand response
Demand response
In electricity grids, demand response is similar to dynamic demand mechanisms to manage customer consumption of electricity in response to supply conditions, for example, having electricity customers reduce their consumption at critical times or in response to market prices...
-aware devices and "smart sockets" in the home. Early forms of such Demand side management technologies were dynamic demand
Dynamic demand (electric power)
Dynamic Demand is the name of a semi-passive technology for adjusting load demands on an electrical power grid. The concept is that by monitoring the frequency of the power grid, as well as their own...
aware devices that passively sensed the load on the grid by monitoring changes in the power supply frequency. Devices such as industrial and domestic air conditioners, refrigerators and heaters adjusted their duty cycle to avoid activation during times the grid was suffering a peak condition. Beginning in 2000, Italy's Telegestore Project was the first to network large numbers (27 million) of homes using such smart meters connected via low bandwidth power line communication
Power line communication
Power line communication or power line carrier , also known as power line digital subscriber line , mains communication, power line telecom , power line networking , or broadband over power lines are systems for carrying data on a conductor also used for electric power transmission.A wide range...
. Recent projects use Broadband over Power Line (BPL) communications, or wireless technologies such as mesh networking that is advocated as providing more reliable connections to disparate devices in the home as well as supporting metering of other utilities such as gas and water.
Monitoring and synchronization of wide area networks were revolutionized in the early 1990s when the Bonneville Power Administration
Bonneville Power Administration
The Bonneville Power Administration is an American federal agency based in the Pacific Northwest. BPA was created by an act of Congress in 1937 to market electric power from the Bonneville Dam located on the Columbia River and to construct facilities necessary to transmit that power...
expanded its smart grid research with prototype sensors that are capable of very rapid analysis of anomalies in electricity quality over very large geographic areas. The culmination of this work was the first operational Wide Area Measurement System (WAMS) in 2000. Other countries are rapidly integrating this technology — China will have a comprehensive national WAMS system when its current 5-year economic plan is complete in 2012
First cities with smart grids
The earliest, and still largest, example of a smart grid is the Italian system installed by Enel S.p.A. of Italy. Completed in 2005, the Telegestore project was highly unusual in the utility world because the company designed and manufactured their own meters, acted as their own system integrator, and developed their own system software. The Telegestore project is widely regarded as the first commercial scale use of smart grid technology to the home, and delivers annual savings of 500 million euro at a project cost of 2.1 billion euro.In the US, the city of Austin, Texas
Austin, Texas
Austin is the capital city of the U.S. state of :Texas and the seat of Travis County. Located in Central Texas on the eastern edge of the American Southwest, it is the fourth-largest city in Texas and the 14th most populous city in the United States. It was the third-fastest-growing large city in...
has been working on building its smart grid since 2003, when its utility first replaced 1/3 of its manual meters with smart meters that communicate via a wireless mesh network
Mesh networking
Mesh networking is a type of networking where each node must not only capture and disseminate its own data, but also serve as a relay for other nodes, that is, it must collaborate to propagate the data in the network....
. It currently manages 200,000 devices real-time (smart meters, smart thermostats, and sensors across its service area), and expects to be supporting 500,000 devices real-time in 2009 servicing 1 million consumers and 43,000 businesses. Boulder, Colorado
Boulder, Colorado
Boulder is the county seat and most populous city of Boulder County and the 11th most populous city in the U.S. state of Colorado. Boulder is located at the base of the foothills of the Rocky Mountains at an elevation of...
completed the first phase of its smart grid project in August 2008. Both systems use the smart meter as a gateway to the home automation
Home automation
Home automation is the residential extension of "building automation". It is automation of the home, housework or household activity. Home automation may include centralized control of lighting, HVAC , appliances, and other systems, to provide improved convenience, comfort, energy efficiency and...
network (HAN) that controls smart sockets and devices. Some HAN designers favor decoupling control functions from the meter, out of concern of future mismatches with new standards and technologies available from the fast moving business segment of home electronic devices.
Hydro One
Hydro One
Hydro One Incorporated delivers electricity across the Canadian province of Ontario. It is a Corporation established under the Business Corporations Act with a single shareholder, the Government of Ontario....
, in Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
, Canada is in the midst of a large-scale Smart Grid initiative, deploying a standards-compliant communications infrastructure from Trilliant. By the end of 2010, the system will serve 1.3 million customers in the province of Ontario. The initiative won the "Best AMR Initiative in North America" award from the Utility Planning Network.
The City of Mannheim
Mannheim
Mannheim is a city in southwestern Germany. With about 315,000 inhabitants, Mannheim is the second-largest city in the Bundesland of Baden-Württemberg, following the capital city of Stuttgart....
in Germany is using realtime Broadband Powerline (BPL) communications in its Model City Mannheim "MoMa" project
InovGrid is an innovative project in Evora
Évora
Évora is a municipality in Portugal. It has total area of with a population of 55,619 inhabitants. It is the seat of the Évora District and capital of the Alentejo region. The municipality is composed of 19 civil parishes, and is located in Évora District....
that aims to equip the electricity grid with information and devices to automate grid management, improve service quality, reduce operating costs, promote energy efficiency and environmental sustainability, and increase the penetration of renewable energies and electric vehicles.
It will be possible to control and manage the state of the entire electricity distribution grid at any given instant, allowing suppliers and energy services companies to use this technological platform to offer consumers information and added-value energy products and services.
This project to install an intelligent energy grid places Portugal and EDP at the cutting edge of technological innovation and service provision in Europe.
Respond to many conditions in supply and demand
LatencyLatency (engineering)
Latency is a measure of time delay experienced in a system, the precise definition of which depends on the system and the time being measured. Latencies may have different meaning in different contexts.-Packet-switched networks:...
of the data flow is a major concern, with some early smart meter architectures allowing actually as long as 24 hours delay in receiving the data, preventing any possible reaction by either supplying or demanding devices.
Smart energy demand
Smart energy demand describes the energy user component of the smart grid. It goes beyond and means much more than even energy efficiencyEfficient energy use
Efficient energy use, sometimes simply called energy efficiency, is the goal of efforts to reduce the amount of energy required to provide products and services. For example, insulating a home allows a building to use less heating and cooling energy to achieve and maintain a comfortable temperature...
and demand response
Demand response
In electricity grids, demand response is similar to dynamic demand mechanisms to manage customer consumption of electricity in response to supply conditions, for example, having electricity customers reduce their consumption at critical times or in response to market prices...
combined. Smart energy demand is what delivers the majority of smart meter and smart grid benefits.
Smart energy demand is a broad concept. It includes any energy-user actions to:
- Enhancement of reliability
- reduce peak demand,
- shift usage to off-peak hours,
- lower total energy consumption,
- actively manage electric vehicle charging,
- actively manage other usage to respond to solar, wind, and other renewable resources, and
- buy more efficient appliances and equipment over time based on a better understanding of how energy is used by each appliance or item of equipment.
All of these actions minimize adverse impacts on electricity grids and maximize consumer savings.
Smart Energy Demand mechanisms and tactics include:
- smart meters,
- dynamic pricing,
- smart thermostats and smart appliances,
- automated control of equipment,
- real-time and next day energy information feedback to electricity users,
- usage by appliance data, and
- scheduling and control of loads such as electric vehicle chargers, home area networks (HANs), and others.
Provision megabits, control power with kilobits, sell the rest
The amount of data required to perform monitoring and switching your appliances off automatically is very small compared with that already reaching even remote homes to support voice, security, Internet and TV services. Many smart grid bandwidth upgrades are paid for by over-provisioning to also support consumer services, and subsidizing the communications with energy-related services or subsidizing the energy-related services, such as higher rates during peak hours, with communications. This is particularly true where governments run both sets of services as a public monopoly, e.g. in India. Because power and communications companies are generally separate commercial enterprises in North America and Europe, it has required considerable government and large-vendor effort to encourage various enterprises to cooperate. Some, like CiscoCisco
Cisco may refer to:Companies:*Cisco Systems, a computer networking company* Certis CISCO, corporatised entity of the former Commercial and Industrial Security Corporation in Singapore...
, see opportunity in providing devices to consumers very similar to those they have long been providing to industry. Others, such as Silver Spring Networks
Silver Spring Networks
Silver Spring Networks is a provider of smart grid products, headquartered in Redwood City, California, with offices in Australia and Brazil. Besides communications devices, Silver Spring Networks develops software for utilities and customers to improve energy efficiency.Founded in 2002 as a...
or Google
Google
Google Inc. is an American multinational public corporation invested in Internet search, cloud computing, and advertising technologies. Google hosts and develops a number of Internet-based services and products, and generates profit primarily from advertising through its AdWords program...
, are data integrators rather than vendors of equipment. While the AC power control standards suggest powerline networking would be the primary means of communication among smart grid and home devices, the bits may not reach the home via Broadband over Power Lines (BPL) initially but by fixed wireless
Fixed wireless
Fixed wireless is the operation of wireless devices or systems used to connect two fixed locations with a radio or other wireless link, such as laser bridge. Usually, fixed wireless is part of a wireless LAN infrastructure. The purpose of a fixed wireless link is to enable data communications...
. This may be only an interim solution, however, as separate power and data connections defeats full control.
Scale and scope
Europe's SuperSmart GridSuperSmart Grid
The SuperSmart Grid is a hypothetical wide area electricity network connecting Europe with northern Africa, the Middle East, Turkey and the IPS/UPS system of CIS countries. The system would unify super grid and smart grid capabilities into a comprehensive network...
, as well as earlier proposals (such as Al Gore
Al Gore
Albert Arnold "Al" Gore, Jr. served as the 45th Vice President of the United States , under President Bill Clinton. He was the Democratic Party's nominee for President in the 2000 U.S. presidential election....
's continental Unified Smart Grid
Unified Smart Grid
Unified National Smart Grid is a proposal for a United States wide area grid that is a national interconnected network relying on a high capacity backbone of electric power transmission lines linking all the nation's local electrical networks that have been upgraded to smart grids...
) make semantic distinctions between local and national grids that sometimes conflict. Papers by Battaglini et al. associate the term "smart grid" with local clusters (page 6), whereas the intelligent interconnecting backbone provides an additional layer of coordination above the local smart grids. Media use in both Europe and the US however tends to conflate national and local.
Regardless of terminology used, smart grid projects always intend to allow the continental and national interconnection backbones to fail without causing local smart grids to fail. As in the case of existing utility infrastructure, they would have to be able to function independently and ration whatever power is available to critical needs.
Municipal grid
Before recent standards efforts, municipal governments, for example in Miami, Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, have historically taken the lead in enforcing integration standards for smart grids/meters. As municipalities or municipal electricity monopolies also often own some fiber optic backbones and control transit exchanges at which communication service providers meet, they are often well positioned to force good integration.
Municipalities also have primary responsibility for emergency response and resilience
Resilience
Resilience is the property of a material to absorb energy when it is deformed elastically and then, upon unloading to have this energy recovered. In other words, it is the maximum energy per unit volume that can be elastically stored...
, and would in most cases have the legal mandate to ration or provision power, say to ensure that hospitals and fire response and shelters have priority and receive whatever power is still available in a general outage.
Home area network
A home area network, or "home grid", extends some of these capabilities into the home using powerline networking and/or RF using standards such as ZigBee
ZigBee
ZigBee is a specification for a suite of high level communication protocols using small, low-power digital radios based on an IEEE 802 standard for personal area networks. Applications include wireless light switches, electrical meters with in-home-displays, and other consumer and industrial...
, INSTEON
INSTEON
Insteon is a system for connecting lighting switches and loads without extra wiring. INSTEON is a dual-band mesh home area networking topology employing AC-power lines and a radio-frequency protocol to communicate with devices...
, Zwave, WiFi
WIFI
WIFI is a radio station broadcasting a brokered format. Licensed to Florence, New Jersey, USA, the station is currently operated by Florence Broadcasting Partners, LLC.This station was previously owned by Real Life Broadcasting...
or others. In the smart grid, NIST is promoting interoperability between the different standards. OSHAN is one initiative that enables interoperability in the home.
Because of the communication standards both smart power grids and some home area networks support more bandwidth than is required for power control and therefore may cost more than required. The existing 802.11 home networks generally have megabits of additional bandwidth for other services (burglary, fire, medical and environmental sensors and alarms, ULC and CCTV monitoring, access control and keying systems, intercoms and secure phone line services), and furthermore can't be separated from LAN
Län
Län and lääni refer to the administrative divisions used in Sweden and previously in Finland. The provinces of Finland were abolished on January 1, 2010....
and VoIP networking, nor from TV once the IPTV
IPTV
Internet Protocol television is a system through which television services are delivered using the Internet protocol suite over a packet-switched network such as the Internet, instead of being delivered through traditional terrestrial, satellite signal, and cable television formats.IPTV services...
standards have emerged.
A number of companies have entered the home area network space, such as Plug Smart, a brand of Juice Technologies, LLC, Tendril, Control4, and EnergyHub.
Consumer electronics devices now consume over half the power in a typical US home. Accordingly, the ability to shut down or hibernate devices when they are not receiving data could be a major factor in cutting energy use, but this would mean the electric company has information on whether a consumer is using their computer or not.
Other key devices that could aide in the utilities efforts to shed load during times of peak demand include air conditioning units, electric water heaters, pool pumps and other high wattage devices.
In 2009, smart grid companies may represent one of the biggest and fastest growing sectors in the "cleantech" market. It consistently receives more than half the venture capital
Venture capital
Venture capital is financial capital provided to early-stage, high-potential, high risk, growth startup companies. The venture capital fund makes money by owning equity in the companies it invests in, which usually have a novel technology or business model in high technology industries, such as...
investment.
In 2009 President Barack Obama
Barack Obama
Barack Hussein Obama II is the 44th and current President of the United States. He is the first African American to hold the office. Obama previously served as a United States Senator from Illinois, from January 2005 until he resigned following his victory in the 2008 presidential election.Born in...
asked the United States Congress
United States Congress
The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....
"to act without delay" to pass legislation that included doubling alternative energy production in the next three years and building a new electricity "smart grid". On April 13, 2009, George W. Arnold was named the first National Coordinator for Smart Grid Interoperability.
What a smart grid is
An electrical grid is not a single entity but an aggregate of multiple networks and multiple power generation companies with multiple operators employing varying levels of communication and coordination, most of which is manually controlled. Smart grids increase the connectivity, automation and coordination between these suppliers, consumers and networks that perform either long distance transmissionElectric power transmission
Electric-power transmission is the bulk transfer of electrical energy, from generating power plants to Electrical substations located near demand centers...
or local distribution
Electric power distribution
File:Electricity grid simple- North America.svg|thumb|380px|right|Simplified diagram of AC electricity distribution from generation stations to consumers...
tasks.
- Transmission networks move electricity in bulk over medium to long distances, are actively managed, and generally operate from 345kV to 800kV over ACAlternating currentIn alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
and DC lines. - Local networks traditionally moved power in one direction, "distributing" the bulk power to consumers and businesses via lines operating at 132kV and lower.
This paradigm is changing as businesses and homes begin generating more wind and solar electricity, enabling them to sell surplus energy back to their utilities. Modernization is necessary for energy consumption efficiency, real time management of power flows and to provide the bi-directional metering
Net metering
Net metering is an electricity policy for consumers who own renewable energy facilities or V2G electric vehicles. "Net", in this context, is used in the sense of meaning "what remains after deductions" — in this case, the deduction of any energy outflows from metered energy inflows...
needed to compensate local producers of power. Although transmission networks are already controlled in real time, many in the US and European countries are antiquated by world standards, and unable to handle modern challenges such as those posed by the intermittent nature of alternative electricity generation, or continental scale
Wide area synchronous grid
A wide area synchronous grid, also called an "interconnection" in North America, is a power grid at a regional scale or greater that operates at a synchronized frequency and is electrically tied together during normal system conditions...
bulk energy transmission.
Modernizes both transmission and distribution
A smart grid is an umbrella term that covers modernization of both the transmissionElectric power transmission
Electric-power transmission is the bulk transfer of electrical energy, from generating power plants to Electrical substations located near demand centers...
and distribution grids. The modernization is directed at a disparate set of goals including facilitating greater competition between providers, enabling greater use of variable energy sources, establishing the automation and monitoring capabilities needed for bulk transmission at cross continent distances, and enabling the use of market forces to drive energy conservation.
Many smart grid features readily apparent to consumers such as smart meter
Smart meter
A smart meter is usually an electrical meter that records consumption of electric energy in intervals of an hour or less and communicates that information at least daily back to the utility for monitoring and billing purposes. Smart meters enable two-way communication between the meter and the...
s serve the energy efficiency goal. The approach is to make it possible for energy suppliers to charge variable electric rates so that charges would reflect the large differences in cost of generating electricity during peak or off peak periods. Such capabilities allow load control switch
Load control switch
A Load control switch is a remotely controlled relay that is placed on home appliances which consume large amounts of electricity, such as air conditioner units and electric water heaters....
es to control large energy consuming devices such as hot water heaters so that they consume electricity when it is cheaper to produce.
Peak curtailment/leveling and time of use pricing
To reduce demand during the high cost peak usage periods, communications and metering technologies inform smart devices in the home and business when energy demand is high and track how much electricity is used and when it is used. It also gives utility companies the ability to reduce consumption by communicating to devices directly in order to prevent system overloads. An example would be a utility reducing the usage of a group of electric vehicle charging stations. To motivate them to cut back use and perform what is called peak curtailment or peak leveling, prices of electricity are increased during high demand periods, and decreased during low demand periods. It is thought that consumers and businesses will tend to consume less during high demand periods if it is possible for consumers and consumer devices to be aware of the high price premium for using electricity at peak periods. This could mean making trade-offs such as cooking dinner at 9 pm instead of 5 pm. When businesses and consumers see a direct economic benefit of using energy at off-peak times become more energy efficient, the theory is that they will include energy cost of operation into their consumer device and building construction decisions. See Time of day metering and demand responseDemand response
In electricity grids, demand response is similar to dynamic demand mechanisms to manage customer consumption of electricity in response to supply conditions, for example, having electricity customers reduce their consumption at critical times or in response to market prices...
.
According to proponents of smart grid plans, this will reduce the amount of spinning reserve that electric utilities have to keep on stand-by, as the load curve
Load curve
]A load curve is a chart showing the amount of electrical energy customers use over the course of time. Power producers use this information to plan how much electricity they will need to make available at any given time...
will level itself through a combination of "invisible hand
Invisible hand
In economics, invisible hand or invisible hand of the market is the term economists use to describe the self-regulating nature of the marketplace. This is a metaphor first coined by the economist Adam Smith...
" free-market capitalism and central control of a large number of devices by power management services that pay consumers a portion of the peak power saved by turning their devices off.
Platform for advanced services
As with other industries, use of robust two-way communications, advanced sensors, and distributed computing technology will improve the efficiency, reliability and safety of power delivery and use. It also opens up the potential for entirely new services or improvements on existing ones, such as fire monitoring and alarms that can shut off power, make phone calls to emergency services, etc.US and UK savings estimates and concerns
One United States Department of EnergyUnited States Department of Energy
The United States Department of Energy is a Cabinet-level department of the United States government concerned with the United States' policies regarding energy and safety in handling nuclear material...
study calculated that internal modernization of US grids with smart grid capabilities would save between 46 and 117 billion dollars over the next 20 years. As well as these industrial modernization benefits, smart grid features could expand energy efficiency beyond the grid into the home by coordinating low priority home devices such as water heaters so that their use of power takes advantage of the most desirable energy sources. Smart grids can also coordinate the production of power from large numbers of small power producers such as owners of rooftop solar panels — an arrangement that would otherwise prove problematic for power systems operators at local utilities.
One important question is whether consumers will act in response to market signals. In the UK, where consumers have for nearly 10 years had a choice in the company from which they purchase electricity, more than 80% have stayed with their existing supplier, despite the fact that there are significant differences in the prices offered by a given electricity supplier.
Another concern is that the cost of telecommunications to fully support smart grids may be prohibitive. A less expensive communication mechanism is proposed using a form of "dynamic demand management
Dynamic demand (electric power)
Dynamic Demand is the name of a semi-passive technology for adjusting load demands on an electrical power grid. The concept is that by monitoring the frequency of the power grid, as well as their own...
" where devices shave peaks by shifting their loads in reaction to grid frequency. Grid frequency could be used to communicate load information without the need of an additional telecommunication network, but it would not support economic bargaining or quantification of contributions.
Although there are specific and proven smart grid technologies in use, smart grid is an aggregate term for a set of related technologies on which a specification is generally agreed, rather than a name for a specific technology. Some of the benefits of such a modernized electricity network include the ability to reduce power consumption at the consumer side during peak hours, called demand side management; enabling grid connection
Grid connection
In electrical grids, a power system network integrates transmission grids, distribution grids, distributed generators and loads that have connection points called busses. A bus in home circuit breaker panels is much smaller than those used on the grid, where busbars can be 50 mm in diameter...
of distributed generation
Distributed generation
Distributed generation, also called on-site generation, dispersed generation, embedded generation, decentralized generation, decentralized energy or distributed energy, generates electricity from many small energy sources....
power (with photovoltaic arrays, small wind turbine
Wind turbine
A wind turbine is a device that converts kinetic energy from the wind into mechanical energy. If the mechanical energy is used to produce electricity, the device may be called a wind generator or wind charger. If the mechanical energy is used to drive machinery, such as for grinding grain or...
s, micro hydro
Micro hydro
Micro hydro is a term used for hydroelectric power installations that typically produce up to 100 kW of electricity. These installations can provide power to an isolated home or small community, or are sometimes connected to electric power networks....
, or even combined heat power generators in buildings); incorporating grid energy storage
Grid energy storage
Grid energy storage refers to the methods used to store electricity on a large scale within an electrical power grid. Electrical energy is stored during times when production exceeds consumption and the stores are used at times when consumption exceeds production...
for distributed generation load balancing; and eliminating or containing failures such as widespread power grid cascading failure
Cascading failure
A cascading failure is a failure in a system of interconnected parts in which the failure of a part can trigger the failure of successive parts.- Cascading failure in power transmission :...
s. The increased efficiency and reliability of the smart grid is expected to save consumers money and help reduce emissions.
Problem definition
The major driving forces to modernize current power grids can be divided in four, general categories.- Increasing reliability, efficiency and safety of the power grid.
- Enabling decentralized power generation so homes can be both an energy client and supplier (provide consumers with an interactive tool to manage energy usage, as net meteringNet meteringNet metering is an electricity policy for consumers who own renewable energy facilities or V2G electric vehicles. "Net", in this context, is used in the sense of meaning "what remains after deductions" — in this case, the deduction of any energy outflows from metered energy inflows...
). - Flexibility of power consumption at the clients side to allow supplier selection (enables distributed generation, solar, wind, biomass).
- Increase GDP by creating more new, green-collarGreen-collar workerA green-collar worker is a worker who is employed in the environmental sectors of the economy. Environmental green-collar workers satisfy the demand for green development. Generally, they implement environmentally conscious design, policy, and technology to improve conservation and sustainability...
energy jobs related to renewable energyRenewable energyRenewable energy is energy which comes from natural resources such as sunlight, wind, rain, tides, and geothermal heat, which are renewable . About 16% of global final energy consumption comes from renewables, with 10% coming from traditional biomass, which is mainly used for heating, and 3.4% from...
industry manufacturing, plug-in electric vehiclePlug-in electric vehicleA plug-in electric vehicle is any motor vehicle that can be recharged from any external source of electricity, such as wall sockets, and the electricity stored in the rechargeable battery packs drives or contributes to drive the wheels...
s, solar panel and wind turbine generation, energy conservation construction.
Smart grid functions
Before examining particular technologies, a proposal can be understood in terms of what it is being required to do. The governments and utilities funding development of grid modernization have defined the functions required for smart grids. According to the United States Department of EnergyUnited States Department of Energy
The United States Department of Energy is a Cabinet-level department of the United States government concerned with the United States' policies regarding energy and safety in handling nuclear material...
's Modern Grid Initiative report, a modern smart grid must:
- Be able to heal itself
- Motivate consumers to actively participate in operations of the grid
- Resist attack
- Provide higher quality power that will save money wasted from outages
- Accommodate all generation and storage options
- Enable electricity markets to flourish
- Run more efficiently
- Enable higher penetration of intermittent power generation sources
Self-healing
Using real-time information from embedded sensors and automated controls to anticipate, detect, and respond to system problems, a smart grid can automatically avoid or mitigate power outages, power quality problems, and service disruptions.As applied to distribution networks, there is no such thing as a "self healing" network. If there is a failure of an overhead power line, given that these tend to operate on a radial basis (for the most part) there is an inevitable loss of power. In the case of urban/city networks that for the most part are fed using underground cables, networks can be designed (through the use of interconnected topologies) such that failure of one part of the network will result in no loss of supply to end users. A fine example of an interconnected network using zoned protection is that of the Merseyside and North Wales Electricity Board (MANWEB
MANWEB
MANWEB was the regional electricity supplier and distributor for Merseyside, North Wales and parts of Cheshire...
).
It is envisioned that the smart grid will likely have a control system that analyzes its performance using distributed, autonomous reinforcement learning
Reinforcement learning
Inspired by behaviorist psychology, reinforcement learning is an area of machine learning in computer science, concerned with how an agent ought to take actions in an environment so as to maximize some notion of cumulative reward...
controllers that have learned successful strategies to govern the behavior of the grid in the face of an ever changing environment such as equipment failures. Such a system might be used to control electronic switches that are tied to multiple substations with varying costs of generation and reliability.
Consumer participation
A smart grid is a means for consumers to change their behavior around variable electric rates or participate in pricing programs designed to ensure reliable electrical service during high-demand conditions. Historically, the intelligence of the grid in North America has been demonstrated by the utilities operating it in the spirit of public service and shared responsibility, ensuring constant availability of electricity at a constant price, day in and day out, in the face of any and all hazards and changing conditions. A smart grid incorporates consumer equipment and behavior in grid design, operation, and communication. This enables consumers to better control “smart appliances” and “intelligent equipment” in homes and businesses, interconnecting energy management systems in “smart buildings” and enabling consumers to better manage energy use and reduce energy costs. Advanced communications capabilities equip customers with tools to take advantage of real-time electricity pricing, incentive-based load reduction signals, or emergency load reduction signals.There is marketing evidence of consumer demand for greater choice. A survey conducted in the summer of 2007 interviewed almost 100 utility executives and sought the opinions of 1,900 households and small businesses from the U.S., Germany, Netherlands, England, Japan and Australia.
Among the findings:
- 83% of those who cannot yet choose their utility provider would welcome that option
- Roughly two-thirds of the customers that do not yet have renewable power options would like the choice
- Almost two-thirds are interested in operating their own generation, provided they can sell power back to the utility
And as already noted, in the UK where the experiment has been running longest, 80% have not changed their utility provider when given the choice (source: National Grid).
Proponents assert that the real-time, two-way communications available in a smart grid will enable consumers to be compensated for their efforts to save energy and to sell energy back to the grid through net-metering
Net metering
Net metering is an electricity policy for consumers who own renewable energy facilities or V2G electric vehicles. "Net", in this context, is used in the sense of meaning "what remains after deductions" — in this case, the deduction of any energy outflows from metered energy inflows...
. By enabling distributed generation resources like residential solar panels, small wind and plug-in hybrid, proponents assert that the smart grid will spark a revolution in the energy industry by allowing small players like individual homes and small businesses to sell power to their neighbors or back to the grid. Many utilities currently promote small independent distributed generation and successfully integrate it with no impact. These sources of power are currently cost-effective with the help government subsidies that are available to help consumers purchase the often expensive equipment that is required.
The same will hold true for larger commercial businesses that have renewable or back-up power systems that can provide power for a price during peak demand events, typically in the summer when air condition units place a strain on the grid. This participation by smaller entities has been called the "democratization of energy"—it is similar to former Vice President Al Gore
Al Gore
Albert Arnold "Al" Gore, Jr. served as the 45th Vice President of the United States , under President Bill Clinton. He was the Democratic Party's nominee for President in the 2000 U.S. presidential election....
's vision for a Unified Smart Grid
Unified Smart Grid
Unified National Smart Grid is a proposal for a United States wide area grid that is a national interconnected network relying on a high capacity backbone of electric power transmission lines linking all the nation's local electrical networks that have been upgraded to smart grids...
.
Resist attack
Smart grid technologies better identify and respond to man-made or natural disruptions. Real-time information enables grid operators to isolate affected areas and redirect power flows around damaged facilities.One of the most important issues of resist attack is the smart monitoring of power grids, which is the basis of control and management of smart grids to avoid or mitigate the system-wide disruptions like blackouts. The traditional monitoring is based on weighted least square (WLS) which is very weak and prone to fail when gross errors (including topology errors, measurement errors or parameter errors) are present. New technology of state monitor is needed to achieve the goals of the smart grids.
High quality power
Outages and power quality issues cost US businesses more than $100 billion on average each year. It is asserted that assuring more stable power provided by smart grid technologies will reduce downtime and prevent such high losses, but the reliability of complex systems is very difficult to analyze and guarantee. A more practical approach to improving reliability and power quality is to simply follow the well established and well documented engineering principles developed by federal agencies like the USDA's Rural Utility Service.Accommodate generation options
As smart grids continue to support traditional power loads they also seamlessly interconnect fuel cells, renewables, microturbines, and other distributed generation technologies at local and regional levels. Integration of small-scale, localized, or on-site power generation allows residential, commercial, and industrial customers to self-generate and sell excess power to the grid with minimal technical or regulatory barriers. This also improves reliability and power quality, reduces electricity costs, and offers more customer choice. It will be a long time before a smart grid is actually necessary to realize these benefits. The existing grid can typically accommodate an order of magnitude more than the existing small-scale localized generation without the benefit of the smart grid. Most obstacles to the integration of larger renewable projects, like wind farms, is due to limitations of traditional infrastructure.Enable electricity market
Significant increases in bulk transmission capacity will require construction of new transmission lines before improvements in transmission grid management proposed by smart grids can make a difference. Such improvements are aimed at creating an open marketplace where alternative energy sources from geographically distant locations can easily be sold to customers wherever they are located.Intelligence in distribution grids are not required to enable small producers to generate and sell electricity at the local level using alternative sources such as rooftop-mounted photo voltaic panels, small-scale wind turbines, and micro hydro generators. For example Chelan PUD's SNAP program promotes distributed, consumer owned small scale generation. Only after very high penetration of these types of resources is additional intelligence provided by sensors and software designed to react instantaneously to imbalances caused by intermittent sources, such as distributed generation, necessary.
Optimize assets
A smart grid can optimize capital assets while minimizing operations and maintenance costs. Optimized power flows reduce waste and maximize use of lowest-cost generation resources. Harmonizing local distribution with inter-regional energy flows and transmission traffic improves use of existing grid assets and reduces grid congestion and bottlenecks, which can ultimately produce consumer savings.Enable high penetration of intermittent generation sources
Climate change and environmental concerns will increase the amount of renewable energy resources. These are for the most part intermittent in nature. Smart Grid technologies will enable power systems to operate with larger amounts of such energy resources since they enable both the suppliers and consumers to compensate for such intermittency.Features
Existing and planned implementations of smart grids provide a wide range of features to perform the required functions.Load adjustment
The total load connected to the power grid can vary significantly over time. Although the total load is the sum of many individual choices of the clients, the overall load is not a stable, slow varying, average power consumption. Imagine the increment of the load if a popular television program starts and millions of televisions will draw current instantly. Traditionally, to respond to a rapid increase in power consumption, faster than the start-up time of a large generator, some spare generators are put on a dissipative standby mode. A smart grid may warn all individual television sets, or another larger customer, to reduce the load temporarily (to allow time to start up a larger generator) or continuously (in the case of limited resources). Using mathematical prediction algorithms it is possible to predict how many standby generators need to be used, to reach a certain failure rate. In the traditional grid, the failure rate can only be reduced at the cost of more standby generators. In a smart grid, the load reduction by even a small portion of the clients may eliminate the problem.Demand response support
Demand responseDemand response
In electricity grids, demand response is similar to dynamic demand mechanisms to manage customer consumption of electricity in response to supply conditions, for example, having electricity customers reduce their consumption at critical times or in response to market prices...
support allows generators and loads to interact in an automated fashion in real time, coordinating demand to flatten spikes. Eliminating the fraction of demand that occurs in these spikes eliminates the cost of adding reserve generators, cuts wear and tear
Wear and tear
Wear and tear is damage that naturally and inevitably occurs as a result of normal wear or aging. It is used in a legal context for such areas as warranty contracts from manufacturers, which usually stipulate that damage due to wear and tear will not be covered.Wear and tear is a form of...
and extends the life of equipment, and allows users to cut their energy bills by telling low priority devices to use energy only when it is cheapest.
Currently, power grid systems have varying degrees of communication within control systems for their high value assets, such as in generating plants, transmission lines, substations and major energy users. In general information flows one way, from the users and the loads they control back to the utilities. The utilities attempt to meet the demand and succeed or fail to varying degrees (brownout, rolling blackout, uncontrolled blackout). The total amount of power demand by the users can have a very wide probability distribution
Probability distribution
In probability theory, a probability mass, probability density, or probability distribution is a function that describes the probability of a random variable taking certain values....
which requires spare generating plants in standby mode to respond to the rapidly changing power usage. This one-way flow of information is expensive; the last 10% of generating capacity may be required as little as 1% of the time, and brownouts and outages can be costly to consumers.
Greater resilience to loading
Although multiple routes are touted as a feature of the smart grid, the old grid also featured multiple routes. Initial power lines in the grid were built using a radial model, later connectivity was guaranteed via multiple routes, referred to as a network structure. However, this created a new problem: if the current flow or related effects across the network exceed the limits of any particular network element, it could fail, and the current would be shunted to other network elements, which eventually may fail also, causing a domino effectDomino effect
The domino effect is a chain reaction that occurs when a small change causes a similar change nearby, which then will cause another similar change, and so on in linear sequence. The term is best known as a mechanical effect, and is used as an analogy to a falling row of dominoes...
. See power outage
Power outage
A power outage is a short- or long-term loss of the electric power to an area.There are many causes of power failures in an electricity network...
. A technique to prevent this is load shedding by rolling blackout
Rolling blackout
A rolling blackout, also referred to as load shedding, is an intentionally-engineered electrical power outage where electricity delivery is stopped for non-overlapping periods of time over geographical regions. Rolling blackouts are a last-resort measure used by an electric utility company in order...
or voltage reduction (brownout).
Decentralization of power generation
Another element of fault tolerance of traditional and smart grids is decentralized power generation. Distributed generationDistributed generation
Distributed generation, also called on-site generation, dispersed generation, embedded generation, decentralized generation, decentralized energy or distributed energy, generates electricity from many small energy sources....
allows individual consumers to generate power onsite, using whatever generation method they find appropriate. This allows individual loads to tailor their generation directly to their load, making them independent from grid power failures. Classic grids were designed for one-way flow of electricity, but if a local sub-network generates more power than it is consuming, the reverse flow can raise safety and reliability issues. A smart grid can manage these situations, but utilities routinely manage this type of situation in the existing grid.
Price signaling to consumers
In many countries, including Belgium, Greece, the Netherlands and the UK, the electric utilities have installed double tariff electricity meterElectricity meter
An electricity meter or energy meter is a device that measures the amount of electric energy consumed by a residence, business, or an electrically powered device....
s in many homes to encourage people to use their electric power during night time or weekends, when the overall demand from industry is very low. During off-peak time the price is reduced significantly, primarily for heating storage radiators or heat pumps with a high thermal mass, but also for domestic appliances. This idea will be further explored in a smart grid, where the price could be changing in seconds and electric equipment is given methods to react on that.
Technology
The bulk of smart grid technologies are already used in other applications such as manufacturing and telecommunications and are being adapted for use in grid operations. In general, smart grid technology can be grouped into five key areas:Integrated communications
Some communications are up to date, but are not uniform because they have been developed in an incremental fashion and not fully integrated. In most cases, data is being collected via modem rather than direct network connection. Areas for improvement include: substation automation, demand response, distribution automation, supervisory control and data acquisition (SCADASCADA
SCADA generally refers to industrial control systems : computer systems that monitor and control industrial, infrastructure, or facility-based processes, as described below:...
), energy management systems, wireless mesh networks and other technologies, power-line carrier communications, and fiber-optics. Integrated communications will allow for real-time control, information and data exchange to optimize system reliability, asset utilization, and security.
Sensing and measurement
Core duties are evaluating congestion and grid stability, monitoring equipment health, energy theft prevention, and control strategies support. Technologies include: advanced microprocessor meters (smart meterSmart meter
A smart meter is usually an electrical meter that records consumption of electric energy in intervals of an hour or less and communicates that information at least daily back to the utility for monitoring and billing purposes. Smart meters enable two-way communication between the meter and the...
) and meter reading equipment, wide-area monitoring systems, dynamic line rating (typically based on online readings by Distributed temperature sensing
Distributed temperature sensing
Distributed temperature sensing systems are optoelectronic devices which measure temperatures by means of optical fibres functioning as linear sensors. Temperatures are recorded along the optical sensor cable, thus not at points, but as a continuous profile. A high accuracy of temperature...
combined with Real time thermal rating (RTTR) systems), electromagnetic signature measurement/analysis, time-of-use and real-time pricing tools, advanced switches and cables, backscatter radio technology, and Digital protective relay
Digital protective relay
In electrical engineering of power systems, a digital protective relay uses a microcontroller with software-based protection algorithms for the detection of electrical faults...
s.
Smart meters
A smart grid replaces analog mechanical meters with digital meters that record usage in real time. Smart meters are similar to Advanced Metering Infrastructure meters and provide a communication path extending from generation plants to electrical outlets (smart socket) and other smart grid-enabled devices. By customer option, such devices can shut down during times of peak demand.Phasor measurement units
High speed sensors called PMUs distributed throughout their network can be used to monitor power quality and in some cases respond automatically to them. Phasors are representations of the waveforms of alternating current, which ideally in real-time, are identical everywhere on the network and conform to the most desirable shape. In the 1980s, it was realized that the clock pulses from global positioning system (GPS)Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...
satellites could be used for very precise time measurements in the grid. With large numbers of PMUs and the ability to compare shapes from alternating current readings everywhere on the grid, research suggests that automated systems will be able to revolutionize the management of power systems by responding to system conditions in a rapid, dynamic fashion.
A wide-area measurement system (WAMS) is a network of PMUS that can provide real-time monitoring on a regional and national scale. Many in the power systems engineering community believe that the Northeast blackout of 2003
Northeast Blackout of 2003
The Northeast blackout of 2003 was a widespread power outage that occurred throughout parts of the Northeastern and Midwestern United States and Ontario, Canada on Thursday, August 14, 2003, just before 4:10 p.m....
would have been contained to a much smaller area if a wide area phasor measurement network was in place.
Advanced components
Innovations in superconductivitySuperconductivity
Superconductivity is a phenomenon of exactly zero electrical resistance occurring in certain materials below a characteristic temperature. It was discovered by Heike Kamerlingh Onnes on April 8, 1911 in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum...
, fault tolerance, storage, power electronics, and diagnostics components are changing fundamental abilities and characteristics of grids. Technologies within these broad R&D categories include: flexible alternating current transmission system devices, high voltage direct current, first and second generation superconducting wire, high temperature superconducting cable, distributed energy generation and storage devices, composite conductors, and “intelligent” appliances.
Advanced control
Power system automationPower system automation
Power system automation is the act of automatically controlling the power system via instrumentation and control devices. Substation automation refers to using data from Intelligent electronic devices , control and automation capabilities within the substation, and control commands from remote...
enables rapid diagnosis of and precise solutions to specific grid disruptions or outages. These technologies rely on and contribute to each of the other four key areas. Three technology categories for advanced control methods are: distributed intelligent agents (control systems), analytical tools (software algorithms and high-speed computers), and operational applications (SCADA, substation automation, demand response, etc.). Using artificial intelligence
Artificial intelligence
Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...
programming techniques, Fujian
Fujian
' , formerly romanised as Fukien or Huguing or Foukien, is a province on the southeast coast of mainland China. Fujian is bordered by Zhejiang to the north, Jiangxi to the west, and Guangdong to the south. Taiwan lies to the east, across the Taiwan Strait...
power grid in China created a wide area protection system that is rapidly able to accurately calculate a control strategy and execute it. The Voltage Stability Monitoring & Control (VSMC) software uses a sensitivity-based successive linear programming
Successive linear programming
Successive Linear Programming , also known as Sequential Linear Programming, is an optimization technique for approximately solving nonlinear optimization problems....
method to reliably determine the optimal control solution.
Improved interfaces and decision support
Information systems that reduce complexity so that operators and managers have tools to effectively and efficiently operate a grid with an increasing number of variables. Technologies include visualization techniques that reduce large quantities of data into easily understood visual formats, software systems that provide multiple options when systems operator actions are required, and simulators for operational training and “what-if” analysis.Standards and groups
IEC TC57 has created a family of international standards that can be used as part of the smart grid. These standards include IEC61850 which is an architecture for substation automation, and IEC 61970/61968 – the Common Information Model (CIM). The CIM provides for common semantics to be used for turning data into information.MultiSpeak has created a specification that supports distribution functionality of the smart grid. MultiSpeak has a robust set of integration definitions that supports nearly all of the software interfaces necessary for a distribution utility or for the distribution portion of a vertically integrated utility. MultiSpeak integration is defined using extensible markup language (XML) and web services.
The IEEE has created a standard to support synchrophasors – C37.118.
The UCA International User Group discusses and supports real world experience of the standards used in smart grids.
A utility task group within LonMark International deals with smart grid related issues.
There is a growing trend towards the use of TCP/IP technology as a common communication platform for smart meter applications, so that utilities can deploy multiple communication systems, while using IP technology as a common management platform.
IEEE P2030
IEEE P2030
IEEE P2030 is an IEEE project developing a "Draft Guide for Smart Grid Interoperability of Energy Technology and Information Technology Operation with the Electric Power System , and End-Use Applications and Loads".- Goals :...
is an IEEE project developing a "Draft Guide for Smart Grid Interoperability of Energy Technology and Information Technology Operation with the Electric Power System (EPS), and End-Use Applications and Loads".
NIST has included ITU-T
ITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
G.hn
G.hn
G.hn is the common name for a home network technology family of standards developed under the International Telecommunication Union's Standardization arm and promoted by the HomeGrid Forum...
as one of the "Standards Identified for Implementation" for the Smart Grid "for which it believed there
was strong stakeholder consensus". G.hn is standard for high-speed communications over power lines, phone lines and coaxial cables.
OASIS EnergyInterop' – is an OASIS technical committee developing XML standards for energy interoperation. It's starting point is the California OpenADR standard.
Under the Energy Independence and Security Act of 2007 (EISA), NIST is charged with overseeing the identification and selection of hundreds of standards that will be required to implement the Smart Grid in the U.S. These standards will be referred by NIST to the Federal Energy Regulatory Commission
Federal Energy Regulatory Commission
The Federal Energy Regulatory Commission is the United States federal agency with jurisdiction over interstate electricity sales, wholesale electric rates, hydroelectric licensing, natural gas pricing, and oil pipeline rates...
(FERC). This work has begun, and the first standards have already been selected for inclusion in NIST’s Smart Grid catalog. However, some commentators have suggested that the benefits that could be realized from Smart Grid standardization could be threatened by a growing number of patents that cover Smart Grid architecture and technologies. If patents that cover standardized Smart Grid elements are not revealed until technology is broadly distributed throughout the network (“locked-in”), significant disruption could occur when patent holders seek to collect unanticipated rents from large segments of the market.
Smart power generation
Smart power generation is a concept of matching electricity productionElectricity generation
Electricity generation is the process of generating electric energy from other forms of energy.The fundamental principles of electricity generation were discovered during the 1820s and early 1830s by the British scientist Michael Faraday...
with demand using multiple identical generators which can start, stop and operate efficiently at chosen load, independently of the others, making them suitable for base load
Base load power plant
Baseload is the minimum amount of power that a utility or distribution company must make available to its customers, or the amount of power required to meet minimum demands based on reasonable expectations of customer requirements...
and peaking
Peaking power plant
Peaking power plants, also known as peaker plants, and occasionally just "peakers," are power plants that generally run only when there is a high demand, known as peak demand, for electricity.-Peak hours:...
power generation. Matching supply and demand, called load balancing
Load balancing (electrical power)
Load balancing refers to the use of various techniques by electrical power stations to store excess electrical power during low demand periods for release as demand rises....
, is essential for a stable and reliable supply of electricity. Short-term deviations in the balance lead to frequency variations and a prolonged mismatch results in blackouts
Power outage
A power outage is a short- or long-term loss of the electric power to an area.There are many causes of power failures in an electricity network...
. Operators of power transmission systems
Electric power transmission
Electric-power transmission is the bulk transfer of electrical energy, from generating power plants to Electrical substations located near demand centers...
are charged with the balancing task, matching the power output of the all the generators
Electrical generator
In electricity generation, an electric generator is a device that converts mechanical energy to electrical energy. A generator forces electric charge to flow through an external electrical circuit. It is analogous to a water pump, which causes water to flow...
to the load of their electrical grid. The load balancing task has become much more challenging as increasingly intermittent and variable generators such as wind turbines
Wind turbine
A wind turbine is a device that converts kinetic energy from the wind into mechanical energy. If the mechanical energy is used to produce electricity, the device may be called a wind generator or wind charger. If the mechanical energy is used to drive machinery, such as for grinding grain or...
and solar cells
Solar cell
A solar cell is a solid state electrical device that converts the energy of light directly into electricity by the photovoltaic effect....
are added to the grid, forcing other producers to adapt their output much more frequently than has been required in the past.
First two dynamic grid stability power plants utilizing the concept has been ordered by Elering
Elering
Elering is an electric power transmission system operator in Estonia. Elering was established on 1 November 1998 under the name of Põhivõrk as an operating unit of the Estonian national power company Eesti Energia. On 1 April 2004, it became a private limited company, OÜ Põhivõrk, as a subsidiary...
and will be built by Wärtsilä
Wärtsilä
Wärtsilä is a Finnish corporation which manufactures and services power sources and other equipment in the marine and energy markets. The core products of Wärtsilä include large combustion engines...
in Kiisa
Kiisa
Kiisa is a small borough in Saku Parish, Harju County, Estonia. It has a population of 629 Kiisa has a station on the Edelaraudtee's western route....
, Estonia
Estonia
Estonia , officially the Republic of Estonia , is a state in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia , and to the east by Lake Peipsi and the Russian Federation . Across the Baltic Sea lies...
. Their purpose is to "provide dynamic generation capacity to meet sudden and unexpected drops in the electricity supply." They are scheduled to be ready during 2013 and 2014, and their total output will be 250 MW.
Recent studies
Many different concepts have been used to model intelligent power grids. They are generally studied within the framework of complex systemsComplex systems
Complex systems present problems in mathematical modelling.The equations from which complex system models are developed generally derive from statistical physics, information theory and non-linear dynamics, and represent organized but unpredictable behaviors of systems of nature that are considered...
. In a recent brainstorming session, the power grid was considered within the context of optimal control
Optimal control
Optimal control theory, an extension of the calculus of variations, is a mathematical optimization method for deriving control policies. The method is largely due to the work of Lev Pontryagin and his collaborators in the Soviet Union and Richard Bellman in the United States.-General method:Optimal...
, ecology
Ecology
Ecology is the scientific study of the relations that living organisms have with respect to each other and their natural environment. Variables of interest to ecologists include the composition, distribution, amount , number, and changing states of organisms within and among ecosystems...
, human cognition, glassy dynamics, information theory
Information theory
Information theory is a branch of applied mathematics and electrical engineering involving the quantification of information. Information theory was developed by Claude E. Shannon to find fundamental limits on signal processing operations such as compressing data and on reliably storing and...
, microphysics of clouds, and many others. Here is a selection of the types of analyses that have appeared in recent years.
Protection systems that verify and supervise themselves
Pelqim Spahiu and Ian R. Evans in their study introduced the concept of a substation based smart protection and hybrid Inspection Unit.
Kuramoto oscillators
The Kuramoto model
Kuramoto model
The Kuramoto model, first proposed by Yoshiki Kuramoto , is a mathematical model used to describe synchronization. More specifically, it is a model for the behavior of a large set of coupled oscillators...
is a well-studied system. The power grid has been described in this context as well. The goal is to keep the system in balance, and/or to maintain phase synchronization
Phase synchronization
Phase synchronization is the process by which two or more cyclic signals tend to oscillate with a repeating sequence of relative phase angles.Phase synchronisation is usually applied to two waveforms of the same frequency with identical phase angles with each cycle...
(also known as phase locking). Non-uniform oscillators also help to model different technologies, different types of power generators, patterns of consumption, and so on. The model has also been used to describe the synchronization patterns in the blinking of fireflies.
Bio-systems
Power grids have been related to complex biological systems in many other contexts. In one study, power grids were compared to the dolphin
Dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...
social network. These creatures streamline and/or intensify communication in case of an unusual situation. The intercommunications that enable them to survive are highly complex.
Random fuse networks
In percolation theory
Percolation theory
In mathematics, percolation theory describes the behavior of connected clusters in a random graph. The applications of percolation theory to materials science and other domains are discussed in the article percolation.-Introduction:...
, random fuse
Fuse
The word fuse has several meanings:* Fuse , a device used in electrical systems to protect against excessive current....
networks have been studied. The current density
Current density
Current density is a measure of the density of flow of a conserved charge. Usually the charge is the electric charge, in which case the associated current density is the electric current per unit area of cross section, but the term current density can also be applied to other conserved...
might be too low in some areas, and too strong in others. The analysis can therefore be used to smooth out potential problems in the network. For instance, high-speed computer analysis can predict blown fuses and correct for them, or analyze patterns that might lead to a power outage. It is difficult for humans to predict the long term patterns in complex networks, so fuse and/or diode networks are used instead.
Neural networks
Neural network
Neural network
The term neural network was traditionally used to refer to a network or circuit of biological neurons. The modern usage of the term often refers to artificial neural networks, which are composed of artificial neurons or nodes...
s have been considered for power grid management as well. The references are too numerous to list.
Markov processes
As wind power
Wind power
Wind power is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, windmills for mechanical power, windpumps for water pumping or drainage, or sails to propel ships....
continues to gain popularity, it becomes a necessary ingredient in realistic power grid studies. Off-line storage, wind variability, supply, demand, pricing, and other factors can be modelled as a mathematical game. Here the goal is to develop a winning strategy. Markov process
Markov process
In probability theory and statistics, a Markov process, named after the Russian mathematician Andrey Markov, is a time-varying random phenomenon for which a specific property holds...
es have been used to model and study this type of system.
Maximum entropy
All of these methods are, in one way or another, maximum entropy methods, which is an active area of research. This goes back to the ideas of Shannon, and many other researchers who studied communication networks. Continuing along similar lines today, modern wireless network research often considers the problem of network congestion, and many algorithms are being proposed to minimize it, including game theory, innovative combinations of FDMA, TDMA
Time division multiple access
Time division multiple access is a channel access method for shared medium networks. It allows several users to share the same frequency channel by dividing the signal into different time slots. The users transmit in rapid succession, one after the other, each using its own time slot. This...
, and others.
Obstacles
In Europe and the US, significant impediments exist to the widespread adoption of smart grid technologies, including:- regulatory environments that don't reward utilities for operational efficiency, excluding U.S. awards.
- consumer concerns over privacy,
- social concerns over "fair" availability of electricity,
- social concerns over EnronEnronEnron Corporation was an American energy, commodities, and services company based in Houston, Texas. Before its bankruptcy on December 2, 2001, Enron employed approximately 22,000 staff and was one of the world's leading electricity, natural gas, communications, and pulp and paper companies, with...
style abuses of information leverage, - limited ability of utilities to rapidly transform their business and operational environment to take advantage of smart grid technologies.
- concerns over giving the government mechanisms to control the use of all power using activities.
Before a utility installs an advanced metering system, or any type of smart system
Smart System
Smart systems are defined as miniaturized devices that incorporate functions of sensing, actuation and control. They are capable of describing and analyzing a situation, and taking decisions based on the available data in a predictive or adaptive manner, thereby performing smart actions...
, it must make a business case for the investment. Some components, like the power system stabilizers (PSS) installed on generators are very expensive, require complex integration in the grid's control system, are needed only during emergencies, but are only effective if other suppliers on the network have them. Without any incentive to install them, power suppliers don't. Most utilities find it difficult to justify installing a communications infrastructure for a single application (e.g. meter reading). Because of this, a utility must typically identify several applications that will use the same communications infrastructure – for example, reading a meter, monitoring power quality, remote connection and disconnection of customers, enabling demand response, etc. Ideally, the communications infrastructure will not only support near-term applications, but unanticipated applications that will arise in the future. Regulatory or legislative actions can also drive utilities to implement pieces of a smart grid puzzle. Each utility has a unique set of business, regulatory, and legislative drivers that guide its investments. This means that each utility will take a different path to creating their smart grid and that different utilities will create smart grids at different adoption rates.
Some features of smart grids draw opposition from industries that currently are, or hope to provide similar services. An example is competition with cable and DSL Internet providers from broadband over powerline internet access
Power line communication
Power line communication or power line carrier , also known as power line digital subscriber line , mains communication, power line telecom , power line networking , or broadband over power lines are systems for carrying data on a conductor also used for electric power transmission.A wide range...
. Providers of SCADA control systems for grids have intentionally designed proprietary hardware, protocols and software so that they cannot inter-operate with other systems in order to tie its customers to the vendor.
Market outlook
In 2009, the US smart grid industry was valued at about $21.4 billion – by 2014, it will exceed at least $42.8 billion. Given the success of the smart grids in the U.S., the world market is expected to grow at a faster rate, surging from $69.3 billion in 2009 to $171.4 billion by 2014. With the segments set to benefit the most will be smart metering hardware sellers and makers of software used to transmit and organize the massive amount of data collected by meters.Deployments and deployment attempts
In the so called E-Energy projects several German utilities are creating first nucleolus in six independent model regions.A technology competition identified this model regions to carry out research and development activities with the main objective to create an "Internet of Energy"
One of the first attempted deployments of "smart grid" technologies in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
was rejected in 2009 by electricity regulators
Regulation
Regulation is administrative legislation that constitutes or constrains rights and allocates responsibilities. It can be distinguished from primary legislation on the one hand and judge-made law on the other...
in the Commonwealth of Massachusetts, a US state. According to an article in the Boston Globe, Northeast Utilities' Western Massachusetts Electric Co. subsidiary actually attempted to create a "smart grid" program using public subsidies that would switch low income
Working class
Working class is a term used in the social sciences and in ordinary conversation to describe those employed in lower tier jobs , often extending to those in unemployment or otherwise possessing below-average incomes...
customers from post-pay to pre-pay billing (using "smart card
Smart card
A smart card, chip card, or integrated circuit card , is any pocket-sized card with embedded integrated circuits. A smart card or microprocessor cards contain volatile memory and microprocessor components. The card is made of plastic, generally polyvinyl chloride, but sometimes acrylonitrile...
s") in addition to special hiked "premium" rates for electricity used above a predetermined amount. This plan was rejected by regulators as it "eroded important protections
Consumer protection
Consumer protection laws designed to ensure fair trade competition and the free flow of truthful information in the marketplace. The laws are designed to prevent businesses that engage in fraud or specified unfair practices from gaining an advantage over competitors and may provide additional...
for low-income
Working class
Working class is a term used in the social sciences and in ordinary conversation to describe those employed in lower tier jobs , often extending to those in unemployment or otherwise possessing below-average incomes...
customers against shutoffs". According to the Boston Globe, the plan "unfairly targeted
Discrimination
Discrimination is the prejudicial treatment of an individual based on their membership in a certain group or category. It involves the actual behaviors towards groups such as excluding or restricting members of one group from opportunities that are available to another group. The term began to be...
low-income customers and circumvented Massachusetts laws meant to help struggling consumers
Poverty
Poverty is the lack of a certain amount of material possessions or money. Absolute poverty or destitution is inability to afford basic human needs, which commonly includes clean and fresh water, nutrition, health care, education, clothing and shelter. About 1.7 billion people are estimated to live...
keep the lights on". A spokesman for an environmental group
Environmental movement
The environmental movement, a term that includes the conservation and green politics, is a diverse scientific, social, and political movement for addressing environmental issues....
supportive of smart grid plans and Western Massachusetts' Electric's aforementioned "smart grid" plan, in particular, stated "If used properly, smart grid technology has a lot of potential for reducing peak demand, which would allow us to shut down some of the oldest, dirtiest power plants... It’s a tool."
In the Netherlands a large scale project (>5000 connections, >20 partners) was initiated to demonstrate integrated smart grids technologies, services and business cases.
General economics developments
As customers can choose their electricity suppliers, depending on their different tariff methods, the focus of transportation costs will be increased. Reduction of maintenance and replacements costs will stimulate more advanced control.A smart grid precisely limits electrical power down to the residential level, network small-scale distributed energy generation and storage devices, communicate information on operating status and needs, collect information on prices and grid conditions, and move the grid beyond central control to a collaborative network.
Guidelines and standards
IEEE 2030.2 represents an extension of the work aimed at utility storage systems for transmission and distribution networks. The IEEE P2030IEEE P2030
IEEE P2030 is an IEEE project developing a "Draft Guide for Smart Grid Interoperability of Energy Technology and Information Technology Operation with the Electric Power System , and End-Use Applications and Loads".- Goals :...
group expects to deliver early 2011 an overarching set of guidelines on smart grid interfaces. The new guidelines will cover areas including batteries and supercapacitor
Supercapacitor
An electric double-layer capacitor , also known as supercapacitor, supercondenser, electrochemical double layer capacitor, or ultracapacitor, is an electrochemical capacitor with relatively high energy density. Their energy density is typically hundreds of times greater than conventional...
s as well as flywheel
Flywheel
A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheels have a significant moment of inertia, and thus resist changes in rotational speed. The amount of energy stored in a flywheel is proportional to the square of its rotational speed...
s. the group has also spun out a 2030.1 effort drafting guidelines for integrating electric vehicle
Electric vehicle
An electric vehicle , also referred to as an electric drive vehicle, uses one or more electric motors or traction motors for propulsion...
s into the smart grid.
See also
- Charging stationCharging stationAn electric vehicle charging station, also called EV charging station, electric recharging point, charging point and EVSE , is an element in an infrastructure that supplies electric energy for the recharging of electric vehicles, plug-in hybrid electric-gasoline vehicles) or semi-static and mobile...
- Grid friendlyGrid friendlyElectrical devices are considered grid friendly if they operate in a manner that supports electrical power grid reliability. Basic grid-friendly devices may incorporate features that work to offset short-term undesirable changes in line frequency or voltage; more sophisticated devices may alter...
- Home automationHome automationHome automation is the residential extension of "building automation". It is automation of the home, housework or household activity. Home automation may include centralized control of lighting, HVAC , appliances, and other systems, to provide improved convenience, comfort, energy efficiency and...
- Large-scale energy storage
- Net meteringNet meteringNet metering is an electricity policy for consumers who own renewable energy facilities or V2G electric vehicles. "Net", in this context, is used in the sense of meaning "what remains after deductions" — in this case, the deduction of any energy outflows from metered energy inflows...
- Pickens planPickens PlanThe Pickens Plan is an energy policy proposal announced July 8, 2008 by American businessman T. Boone Pickens. Pickens wants to reduce American dependence on imported oil by investing approximately $US1 trillion in new wind turbine farms for power generation, which he believes would allow the...
- Power line communicationPower line communicationPower line communication or power line carrier , also known as power line digital subscriber line , mains communication, power line telecom , power line networking , or broadband over power lines are systems for carrying data on a conductor also used for electric power transmission.A wide range...
- Smart grids by countrySmart grids by country-Australia:The Australian government has committed to investing $100 m in smart grids. The federal government's call for proposals to study smart grid technology in 2009 was followed by an announcement of a winning team in June 2010...
- Smart meterSmart meterA smart meter is usually an electrical meter that records consumption of electric energy in intervals of an hour or less and communicates that information at least daily back to the utility for monitoring and billing purposes. Smart meters enable two-way communication between the meter and the...
- SuperSmart GridSuperSmart GridThe SuperSmart Grid is a hypothetical wide area electricity network connecting Europe with northern Africa, the Middle East, Turkey and the IPS/UPS system of CIS countries. The system would unify super grid and smart grid capabilities into a comprehensive network...
- Super gridSuper gridA super grid is a wide area transmission network that makes it possible to trade high volumes of electricity across great distances. It is sometimes also referred to as a "mega grid".-History:...
- Vehicle-to-gridVehicle-to-gridVehicle-to-grid describes a system in which plug-in electric vehicles, such as electric cars and plug-in hybrids , communicate with the power grid to sell demand response services by either delivering electricity into the grid or by throttling their charging rate.Vehicle-to-grid can be used with...
- Virtual power plantVirtual power plantA virtual power plant is a cluster of distributed generation installations which are collectively run by a central control entity....
- Wavelength-division multiplexingWavelength-division multiplexingIn fiber-optic communications, wavelength-division multiplexing is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths of laser light...
- Wide area synchronous gridWide area synchronous gridA wide area synchronous grid, also called an "interconnection" in North America, is a power grid at a regional scale or greater that operates at a synchronized frequency and is electrically tied together during normal system conditions...
External links
- IEEE SmartGrid Portal IEEE's collection of SmartGrid resources
- Smart Grids (European CommissionEuropean CommissionThe European Commission is the executive body of the European Union. The body is responsible for proposing legislation, implementing decisions, upholding the Union's treaties and the general day-to-day running of the Union....
) - The NIST Smart Grid Collaboration Site NIST's public wiki for Smart Grid
- Video Lecture: Computer System Security: Technical and Social Challenges in Creating a Trustworthy Power Grid, University of Illinois at Urbana-ChampaignUniversity of Illinois at Urbana-ChampaignThe University of Illinois at Urbana–Champaign is a large public research-intensive university in the state of Illinois, United States. It is the flagship campus of the University of Illinois system...
- Video Lecture: Smart Grid: Key to a Sustainable Energy Infrastructure, University of Illinois at Urbana-ChampaignUniversity of Illinois at Urbana-ChampaignThe University of Illinois at Urbana–Champaign is a large public research-intensive university in the state of Illinois, United States. It is the flagship campus of the University of Illinois system...
- The IDEAS project (University of Southampton project developing agent-based mechanisms for the Smart Grid)
- http://www.computational-sustainability.org/Institute for Computational SustainabilityInstitute for Computational SustainabilityThe Institute for Computational Sustainability , founded in 2008 with support from an Expeditions in Computing grant from the National Science Foundation, focuses on the newly emerging field of Computational Sustainability and aims to apply computational techniques to help solve some of the most...
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