Renewable energy consumption increased by about 8% between 2008 and 2009, contributing about 8% of the Nation’s total energy demand, and 10% of total U.S. electricity generation in 2009. While renewably energy resources are naturally replenishing, many – such as wind and solar – are flow-limited, meaning they are not available 24/7 to generate electricity. They currently need back-up generation by fossil fuels such as coal or natural gas or storage capacity to provide reliable around the clock service.
Despite their limitations, renewable forms of energy, particularly wind, solar and geothermal, have their place in meeting our country’s energy needs. Putting a price on carbon dioxide emissions would make them more economically appealing.
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Solar and Geothermal
Solar. Despite sunlight’s significant potential for supplying energy, solar power provides less than 1% of U.S. energy needs. This percentage is expected to increase with the development of new and more efficient solar technologies. Currently, solar technologies produce few negative environmental impacts during collector operation. However, there are substantial environmental concerns associated with the current production of collectors and storage devices that also need to be taken into account when evaluating the benefits of solar energy.
Geothermal. At just 0.4%, of our total energy supply, the United States generates more electricity from geothermal energy than any other country in the world. However, conventional geothermal fields, which produce hot steam that can be used directly in turbines, have limited potential for expansion, and enhanced geothermal development which includes fracturing hot, dry rock in regions heated by the Earth’s molten interior poses engineering challenges and environmental concerns.
Wind Power is the fastest growing energy resource in the world. During 2009, the United States increased its wind power capacity by 39%, reflecting the rapid growth trends in recent years. A significant portion of the new wind power came online in the Great Plains states of North Dakota, South Dakota, Illinois, Iowa and Kansas.
In 2009, wind power brought 38 new manufacturing facilities online in the U.S., creating jobs and economic growth. Iowa is a leading wind producer, with the highest percent of wind energy generated to produce electricity by any state (close to 20%).
And just this past year, estimates of the amount of wind power that theoretically could be generated in the United States tripled. According to a new analysis by the National Renewable Energy Laboratory, the “big jump” in potential generation reflects technological change in wind machines more than fundamental new knowledge about our nation’s windscape: “Wind speed generally increases with height, and most wind turbines are taller than they used to be, standing at about 250 feet (80 meters) instead of 165 feet (50 meters). Turbines are now larger, more powerful and better than the old designs that were used to calculate previous estimates”.