Renewable energy debate
Encyclopedia
There is a renewable energy debate about the constraints and opportunities associated with the use of renewable energy
Renewable energy
Renewable 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...

.

Renewable electricity production, from sources such 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....

 and solar power
Solar power
Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available...

, is sometimes criticized for being variable or intermittent
Intermittent power source
An intermittent energy source is any source of energy that is not continuously available due to some factor outside direct control. The intermittent source may be quite predictable, for example, tidal power, but cannot be dispatched to meet the demand of a power system. Examples of intermittent...

. However, the International Energy Agency
International Energy Agency
The International Energy Agency is a Paris-based autonomous intergovernmental organization established in the framework of the Organisation for Economic Co-operation and Development in 1974 in the wake of the 1973 oil crisis...

 has stated that deployment of renewable technologies usually increases the diversity of electricity sources and, through local generation, contributes to the flexibility of the system and its resistance to central shocks.

There have been "not in my back yard" (NIMBY) concerns relating to the visual and other impacts of some wind farm
Wind farm
A wind farm is a group of wind turbines in the same location used to produce electric power. A large wind farm may consist of several hundred individual wind turbines, and cover an extended area of hundreds of square miles, but the land between the turbines may be used for agricultural or other...

s, with local residents sometimes fighting or blocking construction. In the USA, the Massachusetts Cape Wind
Cape Wind
The Cape Wind Project is an approved offshore wind farm, on Horseshoe Shoal in Nantucket Sound off Cape Cod in the U.S. state of Massachusetts, proposed by a private developer, Cape Wind Associates, the brainchild of Jim Gordon and a Limited Liability Company set up as a joint business venture...

 project was delayed for years partly because of aesthetic concerns. However, residents in other areas have been more positive and there are many examples of community wind farm developments. According to a town councilor, the overwhelming majority of locals believe that the Ardrossan Wind Farm
Ardrossan Wind Farm
The 24 megawatt Ardrossan Wind Farm in Ardrossan, North Ayrshire, Scotland was officially opened on August 10, 2004. The Vestas factory in Argyll, which now employs more than 200 people, has supplied the wind turbines for the Airtricity development...

 in Scotland has enhanced the area.

The market for renewable energy technologies has continued to grow. Climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...

 concerns, coupled with high oil prices, peak oil
Peak oil
Peak oil is the point in time when the maximum rate of global petroleum extraction is reached, after which the rate of production enters terminal decline. This concept is based on the observed production rates of individual oil wells, projected reserves and the combined production rate of a field...

, and increasing government support, are driving increasing renewable energy legislation, incentives and commercialization
Renewable energy commercialization
Renewable energy commercialization involves the deployment of three generations of renewable energy technologies dating back more than 100 years. First-generation technologies, which are already mature and economically competitive, include biomass, hydroelectricity, geothermal power and heat...

. New government spending, regulation and policies helped the industry weather the 2009 economic crisis better than many other sectors.

Availability, variability, and reliability

The Fukushima I nuclear accidents in Japan have brought new attention to how national energy systems are vulnerable to natural disasters, with climate change is already bringing more weather and climate extremes. These threats to our old energy systems provide a rationale for investing in renewable energy. Shifting to renewable energy "can help us to meet the dual goals of reducing greenhouse gas emissions, thereby limiting future extreme weather and climate impacts, and ensuring reliable, timely, and cost-efficient delivery of energy". Investing in renewable energy can have significant dividends for our energy security.

There is no shortage of renewable energy and a "smart mix" of renewable energy sources can be used to reliably meet electricity demand:

Because the wind blows during stormy conditions when the sun does not shine and the sun often shines on calm days with little wind, combining wind and solar can go a long way toward meeting demand, especially when geothermal provides a steady base and hydroelectric can be called on to fill in the gaps.


As Amory Lovins
Amory Lovins
Amory Bloch Lovins is an American environmental scientist and writer, Chairman and Chief Scientist of the Rocky Mountain Institute. He has worked in the field of energy policy and related areas for four decades...

 has said:

The variability of sun, wind and so on, turns out to be a non-problem if you do several sensible things. One is to diversify your renewables by technology, so that weather conditions bad for one kind are good for another. Second, you diversify by site so they're not all subject to the same weather pattern at the same time because they're in the same place. Third, you use standard weather forecasting techniques to forecast wind, sun and rain, and of course hydro operators do this right now. Fourth, you integrate all your resources — supply side and demand side..."


The combination of diversifying variable renewables by type and location, forecasting their variation, and integrating them with despatchable renewables, flexible fueled generators, and demand response can create a power system that has the potential to meet our needs reliably. Integrating ever-higher levels of renewables is being successfully demonstrated in the real world:

In 2009, eight American and three European authorities, writing in the leading electrical engineers' professional journal, didn't find "a credible and firm technical limit to the amount of wind energy that can be accommodated by electricity grids". In Fact, not one of more than 200 international studies, nor official studies for the eastern and western U.S. regions, nor the International Energy Agency
International Energy Agency
The International Energy Agency is a Paris-based autonomous intergovernmental organization established in the framework of the Organisation for Economic Co-operation and Development in 1974 in the wake of the 1973 oil crisis...

, has found major costs or technical barriers to reliably integrating up to 30% variable renewable supplies into the grid, and in some studies much more.

Renewable electricity supply in the 20-50+% range has already been implemented in several European systems, albeit in the context of a integrated European grid system:

In 2010, four German states, totaling 10 million people, relied on wind power for 43-52% of their annual electricity needs. Denmark isn't far behind, supplying 22% of its power from wind in 2010 (26% in an average wind year). The Extremadura region of Spain is getting up to 25% of its electricity from solar, while the whole country meets 16% of its demand from wind. Just during 2005-2010, Portugal vaulted from 17% to 45% renewable electricity.

Minnkota Power Cooperative, the leading U.S. wind utility in 2009, supplied 38% of its retail sales from the wind.

Mark A. Delucchi and Mark Z. Jacobson
Mark Z. Jacobson
Mark Z. Jacobson is professor of civil and environmental engineering at Stanford University and director of the Atmosphere and Energy Program there...

 report that there are at least seven ways to design and operate variable renewable energy systems so that they will reliably satisfy electricity demand:
  • (A) interconnect geographically-dispersed naturally-variable energy sources (e.g., wind, solar, wave, tidal), which smoothes out electricity supply (and demand) significantly.
  • (B) use complementary and non-variable energy sources (such as hydroelectric power) to fill temporary gaps between demand and wind or solar generation.
  • (C) use “smart” demand-response management to shift flexible loads to a time when more renewable energy is available.
  • (D) store electric power, at the site of generation, (in batteries, hydrogen gas, compressed air, pumped hydroelectirc power, and flywheels), for later use.
  • (E) over-size renewable peak generation capacity to minimize the times when available renewable power is less than demand and to provide spare power to produce hydrogen for flexible transportation and heat uses.
  • (F) store electric power in electric-vehicle batteries, known as "vehicle to grid" or V2G.
  • (G) forecast the weather (winds, sunlight, waves, tides and precipitation) to better plan for energy supply needs.


Jacobson and Delucchi argue that wind, water and solar power can be scaled up in cost-effective ways to meet our energy demands, freeing us from dependence on both fossil fuels and nuclear power. In 2009 they published “A Plan to Power 100 Percent of the Planet With Renewables” in Scientific American. The article addressed a number of issues, such as the worldwide spatial footprint of wind turbines, the availability of scarce materials needed for manufacture of new systems, the ability to produce reliable energy on demand and the average cost per kilowatt hour. A more detailed and updated technical analysis has been published as a two-part article in the journal Energy Policy.

Renewable power technologies reduce dependence on foreign sources of fuel and therefore increase energy security. They decentralise electricity supply so that an accidental or intentional outage affects a smaller amount of capacity than an outage at a larger power station. They improve the reliability of power generation by producing power close to the end-user, and minimise the need to produce, transport and store hazardous fuels. Unlike generators relying on uranium and recycled plutonium, renewable energy is naturally replenished and not subject to the volatility of global fuel markets.

Aesthetics

Both solar and wind have been criticized from an aesthetic point of view. However, methods and opportunities exist to deploy these renewable technologies efficiently and unobtrusively: fixed solar collectors can double as noise barrier
Noise barrier
A noise barrier is an exterior structure designed to protect sensitive land uses from noise pollution...

s along highways, and extensive roadway, parking lot, and roof-top area is currently available; amorphous photovoltaic cells can also be used to tint windows and produce energy. Advocates of renewable energy also argue that current infrastructure is less aesthetically pleasing than alternatives, but sited further from the view of most critics.

Environmental, social and legal considerations

Renewable power technologies have significant environmental benefits since their use tends to avoid air pollution and the dangers and risks of extracting coal or uranium. They generate electricity without releasing significant quantities of CO2 and other greenhouse gases that contribute to climate change.

Land area required

One environmental issue
Environmental issue
Environmental issues are negative aspects of human activity on the biophysical environment. Environmentalism, a social and environmental movement that started in the 1960s, addresses environmental issues through advocacy, education and activism.-Types:...

, particularly with biomass and biofuels, is the large amount of land required to harvest energy, which otherwise could be used for other purposes or left as undeveloped land.
However, it should be pointed out that these fuels may reduce the need for harvesting non-renewable energy sources, such as vast strip-mined areas and slag mountains for coal, safety zones around nuclear plants, and hundreds of square miles being strip-mined for oil sands. These responses, however, do not account for the extremely high biodiversity
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...

 and endemism of land used for ethanol crops, particularly sugar cane.

In the U.S., crops grown for biofuels are the most land- and water-intensive of the renewable energy sources. In 2005, about 12% of the nation’s corn crop (covering 11 million acres (45,000 km²) of farmland) was used to produce four billion gallons of ethanol—which equates to about 2% of annual U.S. gasoline consumption. For biofuels to make a much larger contribution to the energy economy, the industry will have to accelerate the development of new feedstocks, agricultural practices,
and technologies that are more land and water efficient.

The efficiency of biofuels production has increased significantly
and there are new methods to boost biofuel production, although using bioelectricity, by burning the biomass to produce electricity for an electric car, increases the distance that a car can go from a hectare (about 2.5 acres) of crops by 81%, from 30,000 km to 54,000 km per year. However, covering that same hectare with photovoltaics (in relatively sunless Germany or England) allows the electric car to go 3,250,000 km/year, over 100 times as far as from biofuel.

Hydroelectricity

The major advantage of hydroelectric systems is the elimination of the cost of fuel. Other advantages include longer life than fuel-fired generation, low operating costs, and the provision of facilities for water sports. Operation of pumped-storage plants improves the daily load factor of the generation system. Overall, hydroelectric power can be far less expensive than electricity generated from fossil fuels or nuclear energy, and areas with abundant hydroelectric power attract industry.

However, there are several disadvantages of hydroelectricity
Hydroelectricity
Hydroelectricity is the term referring to electricity generated by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy...

 systems. These include: dislocation of people living where the reservoirs are planned, release of significant amounts of carbon dioxide at construction and flooding of the reservoir, disruption of aquatic ecosystems and birdlife, adverse impacts on the river environment, potential risks of sabotage and terrorism, and in rare cases catastrophic failure of the dam wall.

Large hydroelectric power is considered to be a renewable energy by a large number of sources, however, many groups have lobbied for it to be excluded from renewable electricity standards, any initiative to promote the use of renewable energies, and sometimes the definition of renewable itself. Some organizations, including US federal agencies, will specifically refer to "non-hydro renewable energy".

Hydroelectric power is now more difficult to site in developed nations because most major sites within these nations are either already being exploited or may be unavailable for other reasons such as environmental considerations.

In the last twenty years international organizations like International Rivers, Hydropower Reform Coalition, World Commission on Dams, UNEP, World Conservation Union (IUCN), and the World Bank considered changing politics on large dams, as awareness about dams and hydro-energy generation environmental disadvantages grew, especially among affected populations. Hydro-energy and large dams may not be considered "clean" nor "renewable" sources of electricity because of their serious social and environmental impacts.

Wind farms

Mark Diesendorf
Mark Diesendorf
Mark Diesendorf teaches Environmental Studies at the University of New South Wales, Australia. He was formerly Professor of Environmental Science at...

, formerly Professor of Environmental Science at the University of Technology, Sydney
University of Technology, Sydney
The University of Technology Sydney is a university in Sydney, New South Wales, Australia. The university was founded in its current form in 1981, although its origins trace back to the 1870s. UTS is notable for its central location as the only university with its main campuses within the Sydney CBD...

 and a principal research scientist with CSIRO has summarised some of the benefits of onshore wind farms as follows.



Studies of birds and offshore wind farms in Europe have found that there are very few bird collisions. Several offshore wind sites in Europe have been in areas heavily used by seabirds. Improvements in wind turbine design, including a much slower rate of rotation of the blades and a smooth tower base instead of perchable lattice towers, have helped reduce bird mortality at wind farms around the world. However older smaller wind turbines may be hazardous to flying birds. Birds are severely impacted by fossil fuel energy; examples include birds dying from exposure to oil spills, habitat loss from acid rain and mountaintop removal coal mining, and mercury poisoning.

Community debate about wind farms

Many wind power companies work with local communities to reduce environmental and other concerns associated with particular wind farms. In other cases there is direct community ownership of wind farm projects. Appropriate government consultation, planning and approval procedures also help to minimize environmental risks. Some people may still object to wind farms but, according to The Australia Institute
The Australia Institute
The Australia Institute is a left wing Australian think tank conducting public policy research, funded by grants from philanthropic trusts, memberships and commissioned research....

, their concerns should be weighed against the need to address the threats posed by climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...

 and the opinions of the broader community. Surveys of public attitudes across Europe and in many other countries show strong public support for wind power.

In Germany, for example, hundreds of thousands of people have invested in citizens' wind farms across the country and thousands of small and medium sized enterprises are running successful businesses in a new sector that in 2008 employed 90,000 people and generated 8 percent of Germany's electricity. Wind power has gained very high social acceptance in Germany.

In America, wind projects are reported to boost local tax bases, helping to pay for schools, roads and hospitals. Wind projects also revitalize the
economy of rural communities by providing steady income to farmers and other landowners.

The Intrepid Wind Farm
Intrepid Wind Farm
The Intrepid Wind Farm consists of 107 wind turbines, located in Sac and Buena Vista counties in north-west Iowa, has a generating capacity of 160.5 megawatts of electricity, enough to supply some 43,000 homes...

, in Iowa, is an example of one wind farm where the environmental impact of the project has been minimized through consultation and co-operation:


"Making sure the wind farm made as gentle an environmental impact as possible was an important consideration. Therefore, when MidAmerican first began planning the Intrepid site, they worked closely with a number of state and national environmental groups. Using input from such diverse groups as the Iowa Department of Natural Resources
Iowa Department of Natural Resources
The Iowa Department of Natural Resources is a department/agency of the U.S. state of Iowa charged with maintaining state parks and forests; protecting the environment; and managing energy, fish, wildlife, land resources, and water resources of Iowa.The Mission Statement: To conserve and enhance...

, the Nature Conservancy, Iowa State University
Iowa State University
Iowa State University of Science and Technology, more commonly known as Iowa State University , is a public land-grant and space-grant research university located in Ames, Iowa, United States. Iowa State has produced astronauts, scientists, and Nobel and Pulitzer Prize winners, along with a host of...

, the U.S. Fish and Wildlife Service, the Iowa Natural Heritage Foundation, and the Iowa Chapter of the Sierra Club
Sierra Club
The Sierra Club is the oldest, largest, and most influential grassroots environmental organization in the United States. It was founded on May 28, 1892, in San Francisco, California, by the conservationist and preservationist John Muir, who became its first president...

, MidAmerican created a statewide map of areas in the proposed region that contained specific bird populations or habitats. Those areas were then avoided as site planning got underway in earnest. In order to minimize the wind farm's environmental impact even further, MidAmerican also worked in conjunction with the Army Corp of Engineers
United States Army Corps of Engineers
The United States Army Corps of Engineers is a federal agency and a major Army command made up of some 38,000 civilian and military personnel, making it the world's largest public engineering, design and construction management agency...

, to secure all necessary permits related to any potential risk to wetlands in the area. Regular inspections are also conducted to make certain that the wind farm is causing no adverse environmental impact to the region."


Other examples include:
  • January 29, 1997: Baywind Energy Co-operative
    Baywind Energy Co-operative
    Baywind Energy Co-operative was the first co-operative to own wind turbines in the United Kingdom.Baywind was modelled on the similar wind turbine cooperatives and other renewable energy co-operatives that are common in Scandinavia, and was founded as an Industrial and Provident Society in 1996. It...

     began operating a 2.5 megawatt five-turbine wind farm near Ulverston, Cumbria. It was the first co-operative to own wind turbines in the United Kingdom. It has raised two million pounds and has 1,300 members. A proportion of the profits are invested in local community environmental initiatives through the Baywind Energy Conservation Trust.
  • June 29, 2003: After the Cape Wind
    Cape Wind
    The Cape Wind Project is an approved offshore wind farm, on Horseshoe Shoal in Nantucket Sound off Cape Cod in the U.S. state of Massachusetts, proposed by a private developer, Cape Wind Associates, the brainchild of Jim Gordon and a Limited Liability Company set up as a joint business venture...

     project was proposed several miles off the coast of Cape Cod
    Cape Cod
    Cape Cod, often referred to locally as simply the Cape, is a cape in the easternmost portion of the state of Massachusetts, in the Northeastern United States...

    , some people raised objections, including U.S. Senator Ted Kennedy
    Ted Kennedy
    Edward Moore "Ted" Kennedy was a United States Senator from Massachusetts and a member of the Democratic Party. Serving almost 47 years, he was the second most senior member of the Senate when he died and is the fourth-longest-serving senator in United States history...

     who owned a summer home in the area. Although he objected he finally came around and supported the idea. But attitudes to the proposed wind farm have become more positive in recent years. A 2007 public opinion survey found that more than four out of five Massachusetts residents (84 percent) -- including 58 percent of those who live on the Cape—explicitly supported the proposed Cape Wind offshore wind farm.
  • On October 16, 2003 in Galway
    Galway
    Galway or City of Galway is a city in County Galway, Republic of Ireland. It is the sixth largest and the fastest-growing city in Ireland. It is also the third largest city within the Republic and the only city in the Province of Connacht. Located on the west coast of Ireland, it sits on the...

    , Ireland
    Ireland
    Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

    , construction of the foundation of a wind farm caused almost half a square kilometre of bog to slide 2.5 kilometres down a hillside. The slide destroyed an unoccupied farmhouse and blocked two roads. Nearby residents expressed concern over these environmental impacts.
  • On January 12, 2004, it was reported that the Center for Biological Diversity filed a lawsuit against wind farm owners for killing tens of thousands of birds at the Altamont Pass Wind Resource Area near San Francisco, California. In February 2008, a state appeals court upheld an earlier ruling that rejected the lawsuit.
  • January 21, 2005: Three wind turbines on the island of Gigha
    Gigha
    The Isle of Gigha is a small island off the west coast of Kintyre in Scotland. The island forms part of Argyll and Bute and has a population of about 150 people, many of whom speak Scottish Gaelic. The climate is mild with higher than average sunshine hours and the soils are fertile.Gigha has a...

     in Scotland generate up to 675 kW of power. Revenue is produced by selling the electricity to the grid via an intermediary called Green Energy UK. Gigha residents control the whole project and profits are reinvested in the community. Local residents call the turbines "The Three Dancing Ladies".
  • On December 7, 2007, it was reported that some environmentalists opposed a plan to build a wind farm in western Maryland But other local environmentalists say that the environmental effects of wind farms "pale in comparison to coal-burning generators, which add to global warming and lead to acid rain" that is killing trees in the same area.
  • On February 4, 2008, according to British Ministry of Defence turbines create a hole in radar coverage so that aircraft flying overhead are not detectable. In written evidence, Squadron Leader Chris Breedon said: "This obscuration occurs regardless of the height of the aircraft, of the radar and of the turbine."
  • An April 16, 2008 article in the Pittsburgh Post-Gazette
    Pittsburgh Post-Gazette
    The Pittsburgh Post-Gazette, also known simply as the "PG," is the largest daily newspaper serving metropolitan Pittsburgh, Pennsylvania, USA.-Early history:...

     said that three different environmental organizations had raised objections to a proposed wind farm at Shaffer Mountain in northeastern Somerset County, Pennsylvania
    Somerset County, Pennsylvania
    Somerset County is a county located in the state of Pennsylvania. As of 2010, the population was 77,742. Somerset County was created on April 17, 1795, from part of Bedford County and named for Somerset, United Kingdom. Its county seat is Somerset. It is part of the Johnstown, Pennsylvania,...

    , because the wind farm would be a threat to the Indiana bat
    Indiana bat
    The Indiana bat is a medium-sized mouse-eared bat native to North America. It lives primarily in eastern and midwestern states and in parts of the south of the United States. The Indiana bat is gray, black, or chestnut in colour and is 1.2–2 inches and weighs about 1/4 an ounce...

    , which is listed as an endangered species
    Endangered species
    An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...

    .
  • July 25, 2008: The Australian Hepburn Wind Project
    Hepburn Wind Project
    The Hepburn Wind Project is a wind farm built and owned by Hepburn Wind, a community co-operative, and supported by the Victorian Government. The location of the project is Leonards Hill, 10 km south of Daylesford, Victoria, north-west of Melbourne, Victoria...

     is a proposed wind farm, which will be the first Australian community-owned wind farm. The initiative emerged because the community felt that the state and federal governments were not doing enough to address climate change
    Climate change
    Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...

    .
  • August 12, 2008: The Ardrossan Wind Farm
    Ardrossan Wind Farm
    The 24 megawatt Ardrossan Wind Farm in Ardrossan, North Ayrshire, Scotland was officially opened on August 10, 2004. The Vestas factory in Argyll, which now employs more than 200 people, has supplied the wind turbines for the Airtricity development...

     in Scotland has been "overwhelmingly accepted by local people". Instead of spoiling the landscape, they believe it has enhanced the area: "The turbines are impressive looking, bring a calming effect to the town and, contrary to the belief that they would be noisy, we have found them to be silent workhorses".
  • March 22, 2009: Some rural communities in Alberta, Canada want wind power companies to be allowed to develop wind farms on leased Crown land.
  • April 28, 2009: After the McGuinty government opposed calls for a moratorium on the construction of new turbines 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....

    , several protests took place around the province, especially at Queen's Park
    Queen's Park
    There are a number of places in the world called Queen's Park or Queens Park.- Australia :* Queens Park, New South Wales, suburb* Queens Park, Victoria ** Queens Park, Newtown, Victoria Queen's Park Golf Course...

     in Toronto. Residents insist that more studies take place before continuing construction of the devices in their communities.

Longevity issues

Even though a source of renewable energy may last for billions of years, renewable energy infrastructure, like hydroelectric dams, will not last forever, and must be removed and replaced at some point. Events like the shifting of riverbeds, or changing weather patterns could potentially alter or even halt the function of hydroelectric dams, lowering the amount of time they are available to generate electricity. Hydropower dams is also affected by silting which may or may not be cost effective to remove.

Some have claimed that geothermal being a renewable energy source depends on the rate of extraction being slow enough such that depletion does not occur. If depletion does occur, the temperature can regenerate if given a long period of non-use.

The government of Iceland
Iceland
Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

 states: "It should be stressed that the geothermal resource is not strictly renewable in the same sense as the hydro resource." It estimates that Iceland's geothermal energy could provide 1700 MW for over 100 years, compared to the current production of 140 MW. Radioactive elements in the Earth's crust continuously decay, replenishing the heat. The International Energy Agency
International Energy Agency
The International Energy Agency is a Paris-based autonomous intergovernmental organization established in the framework of the Organisation for Economic Co-operation and Development in 1974 in the wake of the 1973 oil crisis...

 classifies geothermal power as renewable.

Biofuels production

All biomass needs to go through some of these steps: it needs to be grown, collected, dried, fermented and burned. All of these steps require resources and an infrastructure.

Some studies contend that ethanol is "energy negative", meaning that it takes more energy to produce than is contained in the final product. However, a large number of recent studies, including a 2006 article in the journal Science offer the opinion that fuels like ethanol are energy positive. Furthermore, fossil fuels also require significant energy inputs which have seldom been accounted for in the past.

Additionally, ethanol is not the only product created during production, and the energy content of the by-products must also be considered. Corn is typically 66% starch and the remaining 33% is not fermented. This unfermented component is called distillers grain, which is high in fats and proteins, and makes good animal feed. In Brazil, where sugar cane is used, the yield is higher, and conversion to ethanol is somewhat more energy efficient than corn. Recent developments with cellulosic ethanol
Cellulosic ethanol
Cellulosic ethanol is a biofuel produced from wood, grasses, or the non-edible parts of plants.It is a type of biofuel produced from lignocellulose, a structural material that comprises much of the mass of plants. Lignocellulose is composed mainly of cellulose, hemicellulose and lignin...

 production may improve yields even further.

According to the International Energy Agency
International Energy Agency
The International Energy Agency is a Paris-based autonomous intergovernmental organization established in the framework of the Organisation for Economic Co-operation and Development in 1974 in the wake of the 1973 oil crisis...

, new biofuels technologies being developed today, notably cellulosic ethanol, could allow biofuels to play a much bigger role in the future than previously thought. Cellulosic ethanol can be made from plant matter composed primarily of inedible cellulose fibers that form the stems and branches of most plants. Crop residues (such as corn stalks, wheat straw and rice straw),
wood waste, and municipal solid waste are potential sources of cellulosic biomass. Dedicated energy crops, such as switchgrass, are also promising cellulose sources that can be sustainably produced
Sustainability
Sustainability is the capacity to endure. For humans, sustainability is the long-term maintenance of well being, which has environmental, economic, and social dimensions, and encompasses the concept of union, an interdependent relationship and mutual responsible position with all living and non...

 in many
regions of the United States.

The ethanol and biodiesel production industries also create jobs in plant construction, operations, and maintenance, mostly in rural communities. According to the Renewable Fuels Association, the ethanol industry created almost 154,000 U.S. jobs in
2005 alone, boosting household income by $5.7 billion. It also contributed about $3.5 billion in tax revenues at the local, state, and federal levels.

Diversification

The U.S. electric power industry now relies on large, central power stations, including coal, natural gas, nuclear, and hydropower plants that together generate more than 95% of the nation’s electricity. Over the next few decades uses of renewable energy could help to diversify the nation’s bulk power supply. Already, appropriate renewable resources (which excludes large hydropower) produce 12% of northern California’s electricity.

Although most of today’s electricity comes from large, central-station power plants, new technologies offer a range of options for generating electricity nearer to where it is needed, saving on the cost of transmitting and distributing power and improving the overall efficiency and reliability of the system.

Improving energy efficiency
Efficient 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...

 represents the most immediate and often the most cost-effective way to reduce oil dependence, improve energy security, and reduce the health and environmental impact of the energy system. By reducing the total energy requirements of the economy, improved energy efficiency could make increased reliance on renewable energy sources more practical and affordable.

Competition with nuclear power

Nuclear power
Nuclear power
Nuclear power is the use of sustained nuclear fission to generate heat and electricity. Nuclear power plants provide about 6% of the world's energy and 13–14% of the world's electricity, with the U.S., France, and Japan together accounting for about 50% of nuclear generated electricity...

 continues to be considered as an alternative to fossil-fuel power sources (see Low carbon power generation), and in 1956, when the first peak oil
Peak oil
Peak oil is the point in time when the maximum rate of global petroleum extraction is reached, after which the rate of production enters terminal decline. This concept is based on the observed production rates of individual oil wells, projected reserves and the combined production rate of a field...

 paper was presented, nuclear energy was presented as the replacement for fossil fuels. However, the prospect of increased nuclear power deployment was seriously undermined in the United States as a result of the Three Mile Island accident
Three Mile Island accident
The Three Mile Island accident was a core meltdown in Unit 2 of the Three Mile Island Nuclear Generating Station in Dauphin County, Pennsylvania near Harrisburg, United States in 1979....

, and in the rest of the world after the Chernobyl disaster
Chernobyl disaster
The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine , which was under the direct jurisdiction of the central authorities in Moscow...

. This trend has been slowly reversing, and several new nuclear reactors are scheduled for construction, however, there is again increasing resistance in light of the 2011 Japanese nuclear accidents
2011 Japanese nuclear accidents
This is a list of articles describing aspects of the nuclear shut-downs, failures, and nuclear meltdowns triggered by the 2011 Tōhoku earthquake and tsunami.-Fukushima nuclear power plants:* Fukushima I Nuclear Power Plant...

.

Physicist Bernard Cohen proposed in 1983 that uranium dissolved in seawater, when used in fast neutron reactor
Fast neutron reactor
A fast neutron reactor or simply a fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons...

s, is effectively inexhaustible and constantly replenished by rivers, and could therefore be considered a renewable source of energy. However, this idea is not universally accepted, and issues such as peak uranium
Peak uranium
Peak uranium is the point in time that the maximum global uranium production rate is reached. After that peak, the rate of production enters a terminal decline. While uranium is used in nuclear weapons, its primary use is for energy generation via nuclear fission of uranium-235 isotope in a nuclear...

 and uranium depletion
Uranium depletion
Uranium depletion is the result of extracting and consuming uranium, a non-renewable resource. The availability of high-grade uranium ore will deplete over time meaning the fuel will become more environmentally and economically expensive to extract....

 are ongoing debates.

An assessment of the full environmental, social and political impacts of both renewable electricity and nuclear power technologies by Benjamin K. Sovacool
Benjamin K. Sovacool
Benjamin K. Sovacool is a Visiting Associate Professor at Vermont Law School and founding Director of the Energy Justice Program at their Institute for Energy and Environment. He was formerly an Assistant Professor and Research Fellow at the National University of Singapore.Sovacool's research...

 concluded that:


"... renewable electricity technologies present policy makers with a superior alternative for minimising the risk of fuel interruptions and shortages, helping improve the fragile transmission network and reducing environmental harm. These smaller and more environmentally friendly generators cost less to construct, produce power in smaller increments and need not rely on continuous government subsidies. They generate little to no waste, have less greenhouse gas emissions per unit of electricity produced and do not contribute significantly to the risk of accidents. In contrast, the costs for nuclear plant construction, fuel, reprocessing, storage, decommissioning and further research are significant. Even modern nuclear reactors run the risk of accidents and failures, shortages of high quality uranium ore may be imminent and the thermoelectric fuel cycle of nuclear plants consumes and sometimes degrades vast quantities of water. Greenhouse gas emissions associated with the nuclear lifecycle are notable and reactors and waste storage sites invariably damage and degrade the natural environment".

Legislative and scientific definitions of renewable energy, used when determining energy projects eligible for subsidies or tax breaks, usually exclude nuclear power.

See also

  • Nuclear power debate
    Nuclear power debate
    The nuclear power debate is about the controversy which has surrounded the deployment and use of nuclear fission reactors to generate electricity from nuclear fuel for civilian purposes...

  • Uranium mining debate
    Uranium mining debate
    The uranium mining debate covers the political and environmental controversies of the mining of uranium for use in either nuclear power or nuclear weapons.-Background:...

  • Environmental effects of wind power
    Environmental effects of wind power
    Compared to the environmental impact of traditional energy sources, the environmental impact of wind power is relatively minor. Wind power consumes no fuel, and emits no air pollution, unlike fossil fuel power sources. The energy consumed to manufacture and transport the materials used to build a...

  • Renewable energy commercialization
    Renewable energy commercialization
    Renewable energy commercialization involves the deployment of three generations of renewable energy technologies dating back more than 100 years. First-generation technologies, which are already mature and economically competitive, include biomass, hydroelectricity, geothermal power and heat...

  • Comparisons of life-cycle greenhouse gas emissions
    Comparisons of life-cycle greenhouse gas emissions
    Comparisons of life-cycle greenhouse gas emissions attempt to calculate the emissions of greenhouse gases or solely carbon dioxide over the full life of a power source, from groundbreaking to fuel sources to waste management back to greenfield status....

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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