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''Renewables in global energy supply: An IEA facts sheet'' , OECD, p. 3. although the technical potential for their use is very large, exceeding all other readily available sources.World Energy Assessment (2001). Renewable energy technologies , chapter 7. Renewable energy technologies are sometimes criticised for being unreliable or unsightly, yet the market is growing for many forms of renewable energy. Wind power has a worldwide installed capacity of 74,223 MW and is widely used in several European countries and the USA. The manufacturing output of the installation is The Geysers in California, with a rated capacity of 750 MW. While there are many large-scale renewable energy projects, renewable technologies are also suited to Small Off-grid Applications , sometimes in rural and remote areas, where energy is often crucial in human development.World Energy Assessment (2001). Renewable energy technologies , p. 221. Kenya has the world's highest household solar ownership rate with roughly 30,000 small (20-100 watt) solar power systems sold per year. What Solar Power Needs Now ''Renewable Energy Access'', 13 August 2007. , GE , Sharp , and Shell are investing in the renewable energy sector. Two oil giants plunge into the wind business: Shell, BP intend to play major role GE Energy MAIN RENEWABLE ENERGY TECHNOLOGIES The majority of renewable energy technologies are directly or indirectly powered by the sun. The Earth-Atmosphere system is in equilibrium such that heat radiation into space is equal to incoming Solar Radiation , the resulting level of energy within the Earth-Atmosphere system can roughly be described as the Earth's "climate." The hydrosphere (water) absorbs a major fraction of the incoming radiation. Most radiation is absorbed at low latitudes around the equator, but this energy is dissipated around the globe in the form of winds and ocean currents. Wave motion may play a role in the process of transferring mechanical energy between the atmosphere and the ocean through wind stress.Renewable Energy, Sorensen, Elsevier 2004 Solar energy is also responsible for the distribution of precipitation which is tapped by hydroelectric projects, and for the growth of plants used to create biofuels. Renewable energy flows involve natural phenomena such as Sunlight , Wind , Tides and Geothermal Heat , as the International Energy Agency explains:
Each of these sources has unique characteristics which influence how and where they are used. Wind power See Also: Wind power ]] Airflows can be used to run Wind Turbine s. Modern wind turbines range from around 600kW to up to 5 MW of rated power, although turbines with rated output of 1.5-3 MW have become the most common for commercial use. The power output of a turbine is a function of the cube of the wind speed, so as wind speed increases, power output increases dramatically.2 Areas where winds are stronger and more constant, such as offshore and high altitude sites, are preferred locations for wind farms. Wind power is the fastest growing of the renewable energy technologies, though it currently provides less than 0.5% of global energy. REN21 2006 global status report on renewables Over the past decade, global installed maximum capacity increased from 2,500 MW in 1992 to just over 40,000 MW at the end of 2003, at an annual growth rate of near 30%. Due to the Intermittency of wind resources, most deployed turbines in the EU produce electricity an average of 25% of the hours in a year (a capacity factor of 25%), Potentials and costs for renewable electricity generation but under favourable wind regimes some reach 35% or higher. Capacity factors are a function of seasonal wind fluctuations and may be higher in winter. It would mean that a typical 5 MW turbine in the EU would have an average output of 1.7 MW. Globally, the long-term technical potential of wind energy is believed to be five times total current global energy production, or 40 times current electricity demand. This could require large amounts of land to be utilized for wind turbines, particularly in areas of higher wind resources. Offshore resources experience mean wind speeds of ~90% greater than that of land, so offshore resources could contribute substantially more energy."Offshore stations experience mean wind speeds at 80 m that are 90% greater than over land on average. Evaluation of global wind power "Overall, the researchers calculated winds at 80 meters feet traveled over the ocean at approximately 8.6 meters per second and at nearly 4.5 meters per second over land and 10 miles per hour, respectively ." Global Wind Map Shows Best Wind Farm Locations (URL accessed , 2006 ) Wind strengths near the Earth's surface vary and thus cannot guarantee continuous power unless combined with other energy sources or storage systems. Some estimates suggest that 1,000 MW of conventional wind generation capacity can be relied on for just 333 MW of continuous power. While this might change as technology evolves, advocates have suggested incorporating wind power with other power sources, or the use of energy storage techniques, with this in mind. It is best used in the context of a system that has significant reserve capacity such as hydro, or reserve load, such as a desalination plant, to mitigate the economic effects of resource variability. Wind Power is renewable and produces no Greenhouse Gas es during operation, such as Carbon Dioxide and Methane . Water power See Also: Water power Energy in water (in the form of motive energy or temperature differences) can be harnessed and used. Since water is about a thousand times denser than air, even a slow flowing stream of water, or moderate sea Swell , can yield considerable amounts of energy. There are many forms of water energy:
Solar energy use See Also: Solar power In this context, "solar energy" refers to energy that is collected from sunlight. Solar energy can be applied in many ways, including to:
Biofuel See Also: Biofuel Plants use Photosynthesis to grow and produce Biomass . Also known as biomatter, biomass can be used directly as fuel or to produce liquid Biofuel . Agriculturally produced biomass fuels, such as Biodiesel , Ethanol and Bagasse (often a by-product of Sugar Cane cultivation) can be burned in Internal Combustion Engine s or Boiler s. Typically biofuel is burned to release its stored chemical energy. Research into more efficient methods of converting biofuels and other fuels into electricity utilizing fuel cells is an area of very active work. Liquid biofuel Liquid biofuel is usually either a bioalcohol such as Ethanol or a bio-oil such as Biodiesel and Straight Vegetable Oil . Biodiesel can be used in modern diesel vehicles with little or no modification to the engine and can be made from waste and virgin vegetable and animal oil and fats ( Lipid s). Virgin vegetable oils can be used in modified diesel engines. In fact the Diesel engine was originally designed to run on vegetable oil rather than fossil fuel. A major benefit of biodiesel is lower emissions. The use of biodiesel reduces emission of carbon monoxide and other hydrocarbons by 20 to 40%. In some areas Corn , Cornstalk s, Sugarbeet s, Sugar Cane , and Switchgrass es are grown specifically to produce Ethanol (also known as grain alcohol) a liquid which can be used in Internal Combustion Engine s and Fuel Cells . Ethanol is being phased into the current energy infrastructure. E85 is a fuel composed of 85% ethanol and 15% gasoline that is sold to consumers. Biobutanol is being developed as an alternative to bioethanol. In the future, there might be bio-synthetic liquid fuel available. It can be produced by the Fischer-Tropsch Process , also called Biomass-To-Liquids (BTL). Status And Perspectives of Biomass-To-Liquid Fuels in the European Union Solid biomass residue can be used as a biofuel]] Direct use is usually in the form of combustible solids, either wood, the biogenic portion of municipal solid waste or combustible field crops. Field crops may be grown specifically for combustion or may be used for other purposes, and the processed plant waste then used for combustion. Most sorts of biomatter, including dried manure, can actually be burnt to heat water and to drive turbines. Sugar Cane Residue , Wheat Chaff , Corn Cobs and other Plant Matter can be, and are, burned quite successfully. The net Carbon Dioxide emissions that are added to the atmosphere by this process are only from the fossil fuel that is consumed to plant, fertilize, harvest and transport the biomass. Processes to harvest biomass from short-rotation is 29.7 MJ/kg of ethanol it would be 5.94 MJ/kg of the cellulose that it is made from. Thus the ethanol contains only about 1/3 as much energy as the cellulose that it was made from. Co-firing cellulose with coal would replace about three times as much fossil fuel as using the cellulose to make ethanol. The replaced coal would produce 0.0946 kg CO2/MJ {Link without Title} while the replaced liquid fuel would produce only about 0.733 kg CO2/MJ so co-firing the cellulose with coal is about 3.8 times more effective at reducing ghg emissions than using it to make ethanol. Solid biomass can also be Gasified , and used as described in the next section. Biogas See Also: Biogas Anaerobic digestion Biogas can easily be produced from current waste streams, such as: paper production, sugar production, sewage, animal waste and so forth. These various waste streams have to be slurried together and allowed to naturally ferment, producing methane gas. This can be done by converting current sewage plants into biogas plants. When a biogas plant has extracted all the methane it can, the remains are sometimes better suitable as fertilizer than the original biomass. Alternatively biogas can be produced via advanced waste processing systems such as Mechanical Biological Treatment . These systems recover the recyclable elements of household waste and process the biodegradable fraction in Anaerobic Digester s. Renewable Natural Gas is a biogas which has been upgraded to a quality similar to Natural Gas . By upgrading the quality to that of natural gas, it becomes possible to distribute the gas to the mass market via gas grid. Geothermal energy See Also: Geothermal energy Geothermal Station in northeast Iceland]] Geothermal energy is energy obtained by tapping the heat of the earth itself, usually from kilometers deep into the Earth's crust. It is expensive to build a power station but operating costs are low resulting in low energy costs for suitable sites. Ultimately, this energy derives from Radioactive Decay in the Earth 's core. Three types of power plants are used to generate power from geothermal energy: dry steam, flash, and binary. Dry steam plants take steam out of fractures in the ground and use it to directly drive a turbine that spins a generator. Flash plants take hot water, usually at temperatures over 200 °C, out of the ground, and allows it to boil as it rises to the surface then separates the steam phase in steam/water separators and then runs the steam through a turbine. In binary plants, the hot water flows through heat exchangers, boiling an organic fluid that spins the turbine. The condensed steam and remaining geothermal fluid from all three types of plants are injected back into the hot rock to pick up more heat. The geothermal energy from the core of the Earth is closer to the surface in some areas than in others. Where hot underground steam or water can be tapped and brought to the surface it may be used to generate electricity. Such Geothermal Power sources exist in certain geologically unstable parts of the world such as Iceland , New Zealand , United States , The Philippines and Italy . The two most prominent areas for this in the United States are in the Yellowstone basin and in northern California . Iceland produced 170 MW geothermal power and heated 86% of all houses in the year 2000 through geothermal energy. Some 8000 MW of capacity is operational in total. There is also the potential to generate geothermal energy from Hot Dry Rocks . Holes at least 3km deep are drilled into the earth. Some of these holes pump water into the earth, while other holes pump hot water out. The heat resource consists of hot underground radiogenic granite rocks, which heat up when there is enough sediment between the rock and the earths surface. Several companies in Australia are exploring this technology. RENEWABLE ENERGY COMMERCIALIZATION See Also: Renewable energy commercialization Costs Renewable energy technologies encompass a broad, diverse array of technologies, and the current status of these different technologies varies considerably. Some technologies are already mature and economically competitive (e.g. geothermal and hydropower), other technologies need additional development steps to become competitive without subsidies. The table shows an overview of costs of various renewable energy technologies. For comparison with the prices in the table, electricity production from a conventional coal-fired plant costs about 4¢/kWh. World Energy Outlook 2004 ; OECD/International Energy Agency 2004. Though in some G8 nations the cost can be significantly higher at 7.88p (~15¢/kWh). EDF energy, UK, general purpose charging scheme, December 2006. Achieving further cost reductions as indicated in the table below requires further technology development, market deployment, and an increase in production capacities to Mass Production levels. Wind power market grows See Also: Wind power ] Figures from the Global Wind Energy Council (GWEC) show that 2006 recorded an increase in installed wind power capacity of 15,197 megawatts (MW), taking the total installed capacity to 74,223 MW, up from 59,091 MW in 2005. Global wind energy markets continue to boom – 2006 another record year Despite constraints facing supply chains for wind turbines, the annual market for wind continued to increase at the rate of 32% following the 2005 record year, in which the market grew by 41%. In terms of economic value, the wind energy sector has become one of the important players in the energy markets, with the total value of new generating equipment installed in 2006 reaching €18 billion, or US$23 billion. The countries with the highest total installed capacity are Germany (20,621 MW), Spain (11,615 MW), the USA (11,603 MW), India (6,270 MW) and Denmark (3,136 MW). In terms of new installed capacity in 2006, the USA lead with 2,454 MW, followed by Germany (2,233 MW), India (1,840 MW), Spain (1,587 MW), China (1,347 MW) and France (810 MW). In the UK, a licence to build the world's largest offshore windfarm, in the Thames estuary, has been granted. The London Array windfarm, 12 miles off Kent and Essex, should eventually consist of 341 turbines, occupying an area of 90 square miles. This is a £1.5 billion, 1,000 megawatt project, which will power one-third of London homes. The windfarm will produce an amount of energy that, if generated by conventional means, would result in 1.9 million tonnes of carbon dioxide emissions every year. It could also make up to 10% of the Government's 2010 renewables target. Windfarms to power a third of London homes New generation of solar thermal plants See Also: List of solar thermal power stations Construction of the largest Solar Thermal power plant to be built in 15 years, in Boulder City, Nevada, is nearly complete. The 64MW Nevada Solar One power plant will generate enough power to meet the electricity needs of about 40,000 households and follows in the steps of the 354MW SEGS solar thermal power plants located in California’s Mojave Desert. While California’s solar plants have generated billions of kilowatt hours of electricity for the past two decades, the Nevada Solar One plant will use new technologies to capture even more energy from the sun. Largest solar power plant in a generation to be built in Nevada The California Solar Initiative As part of Governor Arnold Schwarzenegger's Million Solar Roofs Program, California has set a goal to create 3,000 megawatts of new, solar-produced electricity by 2017 - moving the state toward a cleaner energy future and helping lower the cost of solar systems for consumers. This is a comprehensive $2.8 billion program. The California Solar Initiative The California Solar Initiative offers cash incentives on solar PV systems of up to $2.50 a watt. These incentives, combined with federal tax incentives, can cover up to 50% of the total cost of a solar panel system. The California Solar Initiative There are many financial incentives to support the use of renewable energy in other US states. Financial Incentives in the USA World's largest photovoltaic power plants Construction of a 40 MW solar generation power plant is underway in the Saxon region of Germany. The Waldpolenz Solar Park will consist of some 550,000 thin-film solar modules. The direct current produced in the modules will be converted into alternating current and fed completely into the power grid. Once completed in 2009, the project will be one of the largest photovoltaic projects ever constructed. Currently the biggest PV plant in the world has an output capacity of around 12 megawatts. Phase One of 40 MW German Solar Park Begun , Manchester , England , was clad in PV panels at a cost of £5.5 million. It started feeding electricity to the National Grid in November 2005.]] A large Photovoltaic power project has been completed in Portugal, the Serpa Solar Power Plant is at one of the Europe's sunniest areas. Major solar power plant opens in Portugal The 11 megawatt plant covers 150 acres and is comprised of 52,000 PV panels. The panels are raised 2 metres off the ground and the area will remain productive grazing land. The project will provide enough energy for 8,000 homes and will save an estimated 30,000 tonnes of carbon dioxide emissions per year. Portugal starts huge solar plant World's largest solar photovoltaic power plant to be built A $420 million large-scale Solar Power Station In Victoria is to be the biggest and most efficient solar photovoltaic power station in the world. Australian company Solar Systems will demonstrate its unique, world leading design incorporating space technology in a 154MW solar power station connected to the national grid. The power station will have the capability to concentrate the sun by 500 times onto the solar cells for ultra high power output. The Victorian power station will generate clean electricity directly from the sun to meet the annual needs of over 45,000 homes with zero greenhouse gas emissions. Solar Systems -- 154MW Victorian Project However, when it comes to renewable energy systems and PV, it is not just large systems that matter. Building-integrated Photovoltaic s or "onsite" PV systems have the advantage of being matched to end use energy needs in terms of scale. So the energy is supplied close to where it is needed. Solar Integrated in New Jersey Use of ethanol for transportation 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 partial result, Brazil, which years ago had to import a large share of the petroleum needed for domestic consumption, recently reached complete self-sufficiency in oil. America and Brazil Intersect on Ethanol 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. '', which calls for 7.5 billion gallons of biofuels to be used annually by 2012, will also help to expand the market. American energy: The renewable path to energy security Wave farms expand See Also: Wave farm 8.5 million. Subject to successful operation, a further €70 million is likely to be invested before 2009 on a further 28 machines to generate 525 MW. Primeiro parque mundial de ondas na Póvoa de Varzim 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 3MW generated by four Pelamis machines. Orkney to get 'biggest' wave farm Geothermal energy prospects By the end of 2005 worldwide use of is included, the non-electric use of geothermal energy is estimated at more than 100 GWt (gigawatts of thermal power) and is used commercially in over 70 countries. Renewables global status report 2006 Update During 2005 contracts were placed for an additional 0.5 GW of capacity in the United States, while there were also plants under construction in 11 other countries. Renewables global status report 2006 Update Future potential While currently renewable energy sources only supply a fraction of current energy use (ca. 14% of primary energy use, World Energy Assessment 2001, Chapter 5: Energy Resources (table 5.26), coordinating lead author Hans-Holger Rogner. Available for download at its UNDP site ., mostly from traditional biomass), there is much potential that could be exploited in the future. As the table below illustrates, the technical potential of renewable energy sources is more than 18 times current global Primary Energy use and furthermore several times higher than projected energy use in 2100. in California with flat-plate solar water heating collectors on its roof.]] There are many different ways to assess potentials. The theoretical potential indicates the amount of energy theoretically available for energy purposes, such as, in the case of Solar Power , the amount of incoming radiation at the earth's surface. The technical potential is a more practical estimate of how much could be put to human use by considering Conversion Efficiencies of the available technology and available land area. To give an idea of the constraints, the estimate for solar energy assumes that 1% of the world's unused land surface is used for solar power. The technical potentials generally do not include economic or other environmental constraints, and the potentials that could be realized at an economically competitive level under current conditions and in a short time-frame is lower still. CONSTRAINTS AND OPPORTUNITIES Critics suggest that some renewable energy applications may create pollution, be dangerous, take up large amounts of land, or be incapable of generating a large net amount of energy. Proponents advocate the use of "appropriate renewables", also known as Soft Energy Technologies , as these have many advantages. Availability There is no shortage of solar-derived energy on Earth. Indeed the storages and flows of energy on the planet are very large relative to human needs.
A criticism of some renewable sources is their Intermittent nature. But a variety of renewable sources in combination can overcome this problem. As Amory Lovins explains: : "Stormy weather, bad for direct solar collection, is generally good for windmills and small hydropower plants; dry, sunny weather, bad for hydropower, is ideal for photovoltaics." The fragility of domestic energy Moreover, the proliferation over a large area of generation sites well connected by transport lines improves the average availability, even with a single technology. For example, the likelihood of having no wind-generated electricity throughout a vast region diminishes every time a new wind park goes up. The challenge of variable power supply may be further alleviated by energy storage. Available storage options include Pumped-storage Hydro System s, batteries, hydrogen Fuel Cell s, and thermal mass. Initial investments in such energy storage systems can be high, although the costs can be recovered over the life of the system. Wave energy is continuously available, although wave intensity varies by season. A wave energy scheme installed in Australia generates electricity with an 80% availability factor. Aesthetics Both solar and wind generating stations 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 barriers 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 aethetically pleasing than alternatives, but sited further from the view of most critics. Environmental and social considerations While most renewable energy sources do not produce pollution directly, the materials, industrial processes, and construction equipment used to create them may generate waste and pollution. Some renewable energy systems actually create environmental problems. For instance, older wind turbines can be hazardous to flying birds. Land area required Another environmental issue, 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 exremely high biodiversity 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 km&2) 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. Already, the efficiency of biofuels production has increased significantly American energy: The renewable path to energy security and there are new methods to boost biofuel production. Hyrogen injection could boost biofuel production Hydroelectric Dams 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 major disadvantages of hydroelectric 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. (See Hydroelectricity article for details.) 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. Wind farms is one of the most environmentally friendly sources of renewable energy]] A wind farm, when installed on agricultural land, has one of the lowest environmental impacts of all energy sources: Why Australia needs wind power
Studies of birds and offshore wind farms in Europe have found that there are very few bird collisions.newscientist.com June 2005 Wind turbines a breeze for migrating birds 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.http://www.capewind.org/FAQ-Category8-Cape+Wind+and+the+Environment-Parent0-myfaq-yes.htm#43 Longevity issues 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. Although geothermal sites are capable of providing heat for many decades, eventually specific locations may cool down. It is likely that in these locations, the system was designed too large for the site, since there is only so much energy that can be stored and replenished in a given volume of earth. Some interpret this as meaning a specific geothermal location can undergo depletion, and question whether geothermal energy is truly renewable. The government of (pdf) Allan Clotworthy, Proceedings World Geothermal Congress 2000. (accessed 30 March ) The International Energy Agency classifies geothermal power as renewable. Geodynamics says it has the "hottest rocks on earth" Biofuels production See Also: Ethanol fuel energy balance 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. Ethanol Production Using Corn, Switchgrass, and Wood; Biodiesel Production Using Soybean and Sunflower However, a large number of recent studies, including a 2006 article Ethanol Can Contribute to Energy and Environmental Goals in the prestigious journal ''Science'' offer the consensus 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. University of Minnesota 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 production may improve yields even further. Biofuels look to the next generation According to the International Energy Agency , new biofuels technologies being developed today, notably cellulosic ethanol, could allow biofuels to play a much bigger role in the future than previously thought. International Energy Agency, World Energy Outlook 2006 , page 8 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. Industrial Biotechnology Is Revolutionizing the Production of Ethanol Transportation Fuel , pages 3-4. 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. American Energy -- The Renewable Path to Energy Security 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.3 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 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. OTHER ISSUES Nuclear power See Also: Energy development#Nuclear energy Nuclear power |
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