Sustainable energy

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Sustainable energy is the provision of energy such that it meets the needs of the present without compromising the ability of future generations to meet their needs. A broader interpretation may allow inclusion of fossil fuels and nuclear fission as transitional sources while technology develops, as long as new sources are developed for future generations to use. A narrower interpretation includes only energy sources which are not expected to be depleted in a time frame relevant to the human race.

Sustainable energy sources are most often regarded as including all renewable sources, such as biofuels, solar power, wind power, wave power, geothermal power and tidal power. It usually also includes technologies that improve energy efficiency. Conventional fission power is sometimes referred to as sustainable, but this is controversial politically due to concerns about peak uranium, waste disposal and the risks of disaster due to accident, terrorism, or natural disaster.

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[edit] Distinction from other terms

Some ways in which sustainable energy has been defined are:

  • "Effectively, the provision of energy such that it meets the needs of the future without compromising the ability of future generations to meet their own needs. ...Sustainable Energy has two key components: renewable energy and energy efficiency." – Renewable Energy and Efficiency Partnership (British)[1]
  • "Energy which is replenishable within a human lifetime and causes no long-term damage to the environment." – Jamaica Sustainable Development Network[2]

This sets sustainable energy apart from other renewable energy terminology such as alternative energy and green energy, by focusing on the ability of an energy source to continue providing energy. Sustainable energy can produce some pollution of the environment, as long as it is not sufficient to prohibit heavy use of the source for an indefinite amount of time. Sustainable energy is also distinct from Low-carbon energy, which is only sustainable as in not adding lots of CO2 to the atmosphere.

[edit] Renewable energy technologies

Renewable energy
Wind Turbine
Biofuel
Biomass
Geothermal
Hydropower
Solar power
Tidal power
Wave power
Wind power
Main article: Renewable energy commercialization

Renewable energy technologies are essential contributors to sustainable energy as they generally contribute to world energy security, reducing dependence on fossil fuel resources, and providing opportunities for mitigating greenhouse gases.[3] The International Energy Agency has defined three generations of renewable energy technologies, reaching back more than 100 years:[3]

  • Second-generation technologies include solar heating and cooling, wind power, modern forms of bioenergy, and solar photovoltaics. These are now entering markets as a result of research, development and demonstration (RD&D) investments since the 1980s. The initial investment was prompted by energy security concerns linked to the oil crises of the 1970s but the continuing appeal of these renewables is due, at least in part, to environmental benefits. Many of the technologies reflect significant advancements in materials.

First- and second-generation technologies have entered the markets, and third-generation technologies heavily depend on long term research and development commitments, where the public sector has a role to play.[3]

A 2008 comprehensive cost-benefit analysis review of energy solutions in the context of global warming and other issues ranked wind power combined with battery electric vehicles (BEV) as the most efficient, followed by concentrated solar power, geothermal power, tidal power, photovoltaic, wave power, coal capture and storage, nuclear energy, and finally biofuels.[4]

[edit] First-generation technologies

Hydroelectric dam in cross section
One of many power plants at The Geysers, a geothermal power field in northern California, with a total output of over 750 MW.

First-generation technologies are most competitive in locations with abundant resources. Their future use depends on the exploration of the available resource potential, particularly in developing countries, and on overcoming challenges related to the environment and social acceptance. Among sources of renewable energy, hydroelectric plants have the advantages of being long-lived -- many existing plants have operated for more than 100 years. Also, hydroelectric plants are clean and have few emissions. Criticisms directed at large-scale hydroelectric plants include: dislocation of people living where the reservoirs are planned, and release of significant amounts of carbon dioxide during construction and flooding of the reservoir.[5] However, it has been found that high emissions are associated only with shallow reservoirs in warm (tropical) locales. Generally speaking, hydroelectric plants produce much lower life-cycle emissions than other types of generation. Hydroelectric power, which underwent extensive development during growth of electrification in the 19th and 20th centuries, is experiencing resurgence of development in the 21st century. The areas of greatest hydroelectric growth are the booming economies of Asia. China is the development leader; however, other Asian nations are installing hydropower at a rapid pace. This growth is driven by much increased energy costs -- especially for imported energy -- and widespread desires for more domestically-produced, clean, renewable, and economical generation.

Geothermal power plants can operate 24 hours per day, providing base-load capacity, and the world potential capacity for geothermal power generation is estimated at 85 GW over the next 30 years. However, geothermal power is accessible only in limited areas of the world, including the United States, Central America, Indonesia, East Africa and the Philippines. The costs of geothermal energy have dropped substantially from the systems built in the 1970s.[3] Geothermal heat generation can be competitive in many countries producing geothermal power, or in other regions where the resource is of a lower temperature.

[edit] Second-generation technologies

Markets for second-generation technologies are strong and growing, mainly in countries such as Germany, Spain, the United States, and Japan. The challenge is to broaden the market base for continued growth worldwide. Strategic deployment in one country not only reduces technology costs for users there, but also for those in other countries, contributing to overall cost reductions and performance improvement.[3]

Solar heating systems are a well known second-generation technology and generally consist of solar thermal collectors, a fluid system to move the heat from the collector to its point of usage, and a reservoir or tank for heat storage and subsequent use. The systems may be used to heat domestic hot water, swimming pool water, or for space heating.[6] The heat can also be used for industrial applications or as an energy input for other uses such as cooling equipment.[7] In many climates, a solar heating system can provide a very high percentage (50 to 75%) of domestic hot water energy.

11 MW solar power plant near Serpa, Portugal 38°1′51″N 7°37′22″W / 38.03083°N 7.62278°W / 38.03083; -7.62278

In the 1980s and early 1990s, most photovoltaic modules provided Remote Area Power Supply, but from around 1995, industry efforts have focused increasingly on developing building integrated photovoltaics and power plants for grid connected applications (see photovoltaic power stations article for details). Currently the largest photovoltaic power plant in North America is the Nellis Solar Power Plant (15 MW).[8][9] There is a proposal to build a Solar power station in Victoria, Australia, which would be the world's largest PV power station, at 154 MW.[10] [11] Other large photovoltaic power stations, which have been proposed or are under construction, include the Girassol solar power plant (62 MW),[12] and the Waldpolenz Solar Park (40 MW).[13]

Worldwide installed capacity 1996-2008

Some of the second-generation renewables, such as wind power, have high potential and have already realised relatively low production costs. At the end of 2006, worldwide capacity of wind-powered generators was 74,223 megawatts, and although it currently produces less than 1% of world-wide electricity use, it accounts for approximately 20% of electricity use in Denmark, 9% in Spain, and 7% in Germany.[14][15] However, it may be difficult to site wind turbines in some areas for aesthetic or environmental reasons, and it may be difficult to integrate wind power into electricity grids in some cases.[3]

Sketch of a Parabolic Trough Collector

Solar thermal power stations have been successfully operating in California commercially since the late 1980s, including the largest solar power plant of any kind, the 350 MW Solar Energy Generating Systems. Nevada Solar One is another 64MW plant which has recently opened.[16] Other parabolic trough power plants being proposed are two 50MW plants in Spain, and a 100MW plant in Israel.[17]

Brazil has one of the largest renewable energy programs in the world, involving production of ethanol fuel from sugar cane, and ethanol now provides 18 percent of the country's automotive fuel. As a result of this, together with the exploitation of domestic deep water oil sources, Brazil, which years ago had to import a large share of the petroleum needed for domestic consumption, recently reached complete self-sufficiency in oil.[18][19][20]

Information on pump, California.

Most cars on the road today in the U.S. can run on blends of up to 10% ethanol, and motor vehicle manufacturers already produce vehicles designed to run on much higher ethanol blends. Ford, DaimlerChrysler, and GM are among the automobile companies that sell “flexible-fuel” cars, trucks, and minivans that can use gasoline and ethanol blends ranging from pure gasoline up to 85% ethanol (E85). By mid-2006, there were approximately six million E85-compatible vehicles on U.S. roads.[21]

[edit] Third-generation technologies

Third-generation technologies are still under development and include advanced biomass gasification, biorefinery technologies, solar thermal power stations, hot dry rock geothermal energy, and ocean energy.[3] Third-generation technologies are not yet widely demonstrated or have limited commercialization. Many are on the horizon and may have potential comparable to other renewable energy technologies, but still depend on attracting sufficient attention and RD&D funding.[3]

According to the International Energy Agency, new bioenergy (biofuel) technologies being developed today, notably cellulosic ethanol biorefineries, could allow biofuels to play a much bigger role in the future than previously thought.[22] 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 in many regions of the United States.[23]

In terms of Ocean energy, another third-generation technology, Portugal has the world's first commercial wave farm, the Aguçadora Wave Park, under construction in 2007. The farm will initially use three Pelmis P-750 machines generating 2.25 MW.[24] [25] and costs are put at 8.5 million euro. Subject to successful operation, a further 70 million euro is likely to be invested before 2009 on a further 28 machines to generate 525 MW.[26] Funding for a wave farm in Scotland was announced in February, 2007 by the Scottish Executive, at a cost of over 4 million pounds, as part of a £13 million funding packages for ocean power in Scotland. The farm will be the world's largest with a capacity of 3 MW generated by four Pelamis machines.[27] (see also Wave farm).

In 2007, the world's first turbine to create commercial amounts of energy using tidal power was installed in the narrows of Strangford Lough in Ireland. The 1.2 MW underwater tidal electricity generator takes advantage of the fast tidal flow in the lough which can be up to 4m/s. Although the generator is powerful enough to power up to a thousand homes, the turbine has a minimal environmental impact, as it is almost entirely submerged, and the rotors turn slowly enough that they pose no danger to wildlife.[28][29]

Solar power panels that use nanotechnology, which can create circuits out of individual silicon molecules, may cost half as much as traditional photovoltaic cells, according to executives and investors involved in developing the products. Nanosolar has secured more than $100 million from investors to build a factory for nanotechnology thin-film solar panels. The company's plant has a planned production capacity of 430 megawatts peak power of solar cells per year. Commercial production started and first panels have been shipped[30] to customers in late 2007.[31]

[edit] Energy efficiency

Moving towards energy sustainability will require changes not only in the way energy is supplied, but in the way it is used, and reducing the amount of energy required to deliver various goods or services is essential. Opportunities for improvement on the demand side of the energy equation are as rich and diverse as those on the supply side, and often offer significant economic benefits.[32]

Renewable energy and energy efficiency are sometimes said to be the “twin pillars” of sustainable energy policy. Both resources must be developed in order to stabilize and reduce carbon dioxide emissions. Efficiency slows down energy demand growth so that rising clean energy supplies can make deep cuts in fossil fuel use. If energy use grows too fast, renewable energy development will chase a receding target. Likewise, unless clean energy supplies come online rapidly, slowing demand growth will only begin to reduce total emissions; reducing the carbon content of energy sources is also needed. Any serious vision of a sustainable energy economy thus requires commitments to both renewables and efficiency.[33]

Renewable energy (and energy efficiency) are no longer niche sectors that are promoted only by governments and environmentalists. The increased levels of investment and the fact that much of the capital is coming from more conventional financial actors suggest that sustainable energy options are now becoming mainstream.[34]

Climate change concerns coupled with high oil prices and increasing government support are driving increasing rates of investment in the sustainable energy industries, according to a trend analysis from the United Nations Environment Programme. According to UNEP, global investment in sustainable energy in 2007 was higher than previous levels, with $148 billion of new money raised in 2007, an increase of 60% over 2006. Total financial transactions in sustainable energy, including acquisition activity, was $204 billion.[35]

Investment flows in 2007 broadened and diversified, making the overall picture one of greater breadth and depth of sustainable energy use. The mainstream capital markets are "now fully receptive to sustainable energy companies, supported by a surge in funds destined for clean energy investment".[35]

[edit] Nuclear power

It is said that nuclear has the potential to be sustainable, however, this is often qualified with the argument that there are serious challenges that must be dealt with before it can drastically increase its role.[36]

There are potentially two sources of nuclear power. Fission is used in all current nuclear power plants. Fusion is the reaction that powers stars, including the sun, which remains impractical for use on earth. Both types create radioactive waste in the form of activated structural material, which is one of the sustainability issues.

Fission power's long-term sustainability depends on the amount of uranium and thorium that are available to be mined, on the operators' abilities safely to dispose of the waste and on the continued prevention of major accidents. Estimates for fuel reserves vary widely. Fusion power's long-term sustainability depends on whether or not a practical, affordable technology can be developed.

[edit] Technical sustainability of nuclear power

Proponents, such as Christine Todd Whitman and Patrick Moore (both co-chairs of the Clean and Safe Energy Coalition) also claim that nuclear power is at least as environmentally friendly as traditional sources of renewable energy, making it part of the solution to global warming and the world's currently growing demand for energy. They note that nuclear power plants, once built and before decommissioning begins, produce little carbon dioxide emissions and point out that the radioactive waste produced is minimal and well-contained, especially compared to fossil fuels.[37]

[edit] See also

Energy portal
Sustainable development portal

[edit] References

  1. ^ Renewable Energy and Efficiency Partnership (August 2004). "Glossary of terms in sustainable energy regulation" (pdf). http://www.reeep.org/file_upload/296_tmpphpXkSxyj.pdf. Retrieved on 2008-04-19. 
  2. ^ Jamaica Sustainable Development Network. "Glossary of terms". http://www.jsdnp.org.jm/glossary.html. Retrieved on 2008-04-19. 
  3. ^ a b c d e f g h i International Energy Agency (2007). Renewables in global energy supply: An IEA facts sheet, OECD, 34 pages.
  4. ^ Jacobson, Mark Z. (2009). "Review of solutions to global warming, air pollution, and energy security". Energy and Environmental Science (Royal Society of Chemistry). doi:10.1039/b809990c. http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=EE&Year=2009&ManuscriptID=b809990c&Iss=Advance_Article. Retrieved on 2008-12-21. 
  5. ^ Hydroelectric power's dirty secret revealed New Scientist, 24 February 2005.
  6. ^ Solar water heating
  7. ^ Solar assisted air-conditioning of buildings
  8. ^ Largest U.S. Solar Photovoltaic System Begins Construction at Nellis Air Force Base
  9. ^ Nellis activates Nations largest PV Array
  10. ^ Australia advances with solar power The Times, 26 October 2006.
  11. ^ Solar Systems projects
  12. ^ 62 MW Solar PV Project Quietly Moves Forward Renewable Energy Access, 18 November 2005.
  13. ^ World’s largest solar power plant being built in eastern Germany
  14. ^ Global wind energy markets continue to boom – 2006 another record year
  15. ^ European wind companies grow in U.S.
  16. ^ Solar One is "go" for launch
  17. ^ Israeli company drives the largest solar plant in the world
  18. ^ America and Brazil Intersect on Ethanol Renewable Energy Access, 15 May 2006.
  19. ^ How to manage our oil addiction - CESP
  20. ^ New Rig Brings Brazil Oil Self-Sufficiency Washington Post, 21 April 2006.
  21. ^ Worldwatch Institute and Center for American Progress (2006). American energy: The renewable path to energy security
  22. ^ International Energy Agency (2006). World Energy Outlook 2006 p. 8.
  23. ^ Biotechnology Industry Organization (2007). Industrial Biotechnology Is Revolutionizing the Production of Ethanol Transportation Fuel pp. 3-4.
  24. ^ Sea machine makes waves in Europe BBC News, 15 March 2006.
  25. ^ Wave energy contract goes abroad BBC News, 19 May 2005.
  26. ^ Primeiro parque mundial de ondas na Póvoa de Varzim
  27. ^ Orkney to get 'biggest' wave farm BBC News, 20 February 2007.
  28. ^ Turbine technology is turning the tides into power of the future
  29. ^ SeaGen Turbine Installation Completed
  30. ^ Nanosolar ships first panels
  31. ^ Solar power nanotechnology may cut cost in half, executives say
  32. ^ InterAcademy Council (2007). Lighting the way: Toward a sustainable energy future
  33. ^ American Council for an Energy-Efficient Economy (2007). The Twin Pillars of Sustainable Energy: Synergies between Energy Efficiency and Renewable Energy Technology and Policy Report E074.
  34. ^ United Nations Environment Programme and New Energy Finance Ltd. (2007), p. 17.
  35. ^ a b Global Trends in Sustainable Energy Investment 2008 p. 8.
  36. ^ World Nuclear Association. Nuclear Power and Sustainable Development.
  37. ^ Nuclear Energy Institute. Nuclear Energy Institute - Environmentalists

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