Comparisons of life-cycle greenhouse gas emissions
Encyclopedia
Comparisons of life-cycle greenhouse gas emissions attempt to calculate the emissions of greenhouse gas
Greenhouse gas
A greenhouse gas is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range. This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in the Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone...

es or solely carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 over the full life of a power source, from groundbreaking to fuel sources to waste management back to greenfield
Greenfield status
Greenfield status is a term used to describe an end point wherein a parcel of land that had been in industrial use is, in principle, restored to the conditions existing before the construction of the plant...

 status.

2008 Sovacool survey

A meta analysis of 103 life cycle studies 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...

, found that fossil fueled power plants produce electricity with about 443-1050 g equivalent lifecycle carbon dioxide emissions per kWh, nuclear power plants produce electricity with about 66 g (no range given) equivalent lifecycle carbon dioxide emissions per kWh, and renewable power generators produce electricity with 9.5-38 g carbon dioxide per kWh.

Nuclear energy technologies are thus seven to sixteen times more effective than fossil fuel power plants on a per kWh basis at fighting climate change, and renewable electricity technologies are "two to seven times more effective than nuclear power plants on a per kWh basis at fighting climate change". Such estimates already include all conceivable emissions associated with the manufacturing, construction, installation and decommissioning of renewable power plants.
Lifecycle greenhouse gas emission estimates for electricity generators
Technology Description Estimate
(g CO2/kWhe)
Wind
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....

 
2.5 MW offshore  9
Hydroelectric
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...

 
3.1 MW reservoir 10
Wind 1.5 MW onshore  10
Biogas
Biogas
Biogas typically refers to a gas produced by the biological breakdown of organic matter in the absence of oxygen. Organic waste such as dead plant and animal material, animal dung, and kitchen waste can be converted into a gaseous fuel called biogas...

 
Anaerobic digestion
Anaerobic digestion
Anaerobic digestion is a series of processes in which microorganisms break down biodegradable material in the absence of oxygen. It is used for industrial or domestic purposes to manage waste and/or to release energy....

 
11
Hydroelectric 300 kW run-of-river 13
Solar thermal  80 MW parabolic trough
Parabolic trough
A parabolic trough is a type of solar thermal energy collector. It is constructed as a long parabolic mirror with a Dewar tube running its length at the focal point. Sunlight is reflected by the mirror and concentrated on the Dewar tube...

 
13
Biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....

 
various 14-35
Solar PV  Polycrystaline silicon
Polycrystalline silicon photovoltaics
Polycrystalline silicon photovoltaics are a type of solar cell. Silicon solar cells are manufactured with a microstructure tailored to the application depending on economic and performance requirements.-Forms of silicon:...

 
32
Geothermal
Geothermal
Geothermal is related to energy and may refer to:* The geothermal gradient and associated heat flows from within the Earth- Renewable technology :...

 
80 MW hot dry rock  38
Nuclear
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...

 
various reactor types 66
Natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...

 
various combined cycle turbines 443
Diesel  various generator and turbine types 778
Heavy oil
Fuel oil
Fuel oil is a fraction obtained from petroleum distillation, either as a distillate or a residue. Broadly speaking, fuel oil is any liquid petroleum product that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, except oils having a flash...

 
various generator and turbine types 778
Coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

 
various generator types with scrubbing 960
Coal various generator types without scrubbing 1050

2007 Oxford survey

A 2007 report published by the Oxford Research Group
Oxford Research Group
Oxford Research Group is an independent non-governmental organisation and UK registered charity, which works together with others to promote a more sustainable approach to security for the UK and the world. In April 2005, ORG was named one of the top 20 think tanks in the UK by The Independent...

 listed the following results: coal = 755 g/kWh; natural gas = 385 g/kWh; biomass = 29 - 62 g/kWh; wind = 11 - 37 g/kWh; nuclear = 11 - 130 g/kWh (using the minimum and maximum results amongst 3 studies). The report concluded that "Emissions from nuclear power lie somewhere between biomass and natural gas ... Furthermore, as the available average ore grade declines CO2 (and other Greenhouse Gases) emissions from nuclear power will increase."

Other studies

In terms of individual studies, a wide range of estimates are made for many fuel sources which arise from the different methodologies used. Those on the low end tend to leave parts of the life cycle out of their analyses, while those on the high end often make unrealistic assumptions about the amount of energy used in some parts of the life cycle.

The Intergovernmental Panel on Climate Change
Intergovernmental Panel on Climate Change
The Intergovernmental Panel on Climate Change is a scientific intergovernmental body which provides comprehensive assessments of current scientific, technical and socio-economic information worldwide about the risk of climate change caused by human activity, its potential environmental and...

 states that total life-cycle GHG emissions per unit of electricity produced from nuclear power are below 40 gCO2-eq/kWh (10 gC-eq/kWh), similar to those for renewable energy sources.

A study of life-cycle emissions by Swedish utility Vattenfall
Vattenfall
Vattenfall is a Swedish power company. The name Vattenfall is Swedish for waterfall, and is an abbreviation of its original name, Royal Waterfall Board...

 reported that nuclear power produced 3.3 g CO2/kWh, 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....

 produced 10, natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...

 produced 400 and coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

 700.

Another report - Life-Cycle Energy Balance and Greenhouse Gas Emissions of Nuclear Energy in Australia - conducted by the University of Sydney in 2008 produced the following results: nuclear = 60-65 g CO2/kWh; wind power = 20 g/kWh; solar PV = 106 g/kWh. Furthemore, the study criticised the Vattenfall report : "it omits the energy and greenhouse gas impacts of many upstream contributions".
In a study conducted in 2006 by the UK's Parliamentary Office of Science and Technology
Parliamentary Office of Science and Technology
The Parliamentary Office of Science and Technology, is the Parliament of the United Kingdom's in-house source of independent, balanced and accessible analysis of public policy issues related to science and technology...

 (POST), which used figures from the Torness
Torness nuclear power station
Torness nuclear power station was the last of the United Kingdom's second generation nuclear power plants to be commissioned. Construction of this facility began in 1980 for the then South of Scotland Electricity Board and it was commissioned in 1988...

 study, nuclear power's life cycle was evaluated to emit the least amount of carbon dioxide (very close to wind power's life cycle emissions) when compared to the other alternatives (fossil fuel
Fossil fuel
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years...

, coal
Coal
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure...

, and some 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...

 including biomass
Biomass
Biomass, as a renewable energy source, is biological material from living, or recently living organisms. As an energy source, biomass can either be used directly, or converted into other energy products such as biofuel....

 and PV solar panels).
A 2005 study, issued by stormsmith
Jan Willem Storm van Leeuwen
Jan Willem Storm van Leeuwen is a consultant in chemistry and energy systems with more than thirty years experience in technology assessment.Storm van Leeuwen received his Masters in Science, physical chemistry, at the Technical University Eindhoven. He is a senior scientist at Ceedata...

, reported that carbon dioxide emissions from nuclear power plants per kilowatt hour could range from 20% to 120% of those for natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...

-fired power stations depending on the availability of high grade ores.

See also

  • Carbon capture and storage
    Carbon capture and storage
    Carbon capture and storage , alternatively referred to as carbon capture and sequestration, is a technology to prevent large quantities of from being released into the atmosphere from the use of fossil fuel in power generation and other industries. It is often regarded as a means of mitigating...

  • Efficient energy use
    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...

  • Environmental effects of nuclear power
    Environmental effects of nuclear power
    The environmental impact of nuclear power results from the nuclear fuel cycle, operation, and the effects of nuclear accidents.The routine health risks and greenhouse gas emissions from nuclear fission power are small relative to those associated with coal, but there are "catastrophic risks": the...

  • 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...

  • Relative cost of electricity generated by different sources
  • 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...


External links

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