Renewable energy is clean, affordable, domestic, and effectively infinite. It produces no emissions and results in cleaner air and water for all. Renewable power creates jobs and generates revenue for local communities. Revenue from solar and wind farms helps stimulate local economies that need new roads, schools, libraries, and hospitals.
The United States has some of the best wind resources in the world, with enough potential energy to produce nearly 10 times the country's existing power needs. Wind energy is now one of the most cost-effective sources of new generation, competing with new installations of coal, gas and nuclear power. Its cost has dropped steadily over the past few years, as wind turbine technology has improved. Currently, over 400 American manufacturing plants build wind components, towers and blades.
Solar power can also help meet America's energy demand. Solar installations in the United States exceed 3,100 megawatts, enough to power more than 630,000 homes. The solar industry employs more than 100, 000 Americans and grew by 69 percent in 2010, making it one of the fastest growing sectors in the U.S. The price of solar panels has dropped by 30 percent since 2010 and costs continue to fall. The United States was a net exporter of solar products in 2010 by $2 billion.
Wind and solar energy are reliable sources of electricity that can diversify our nation's energy portfolio. However, continued growth of renewable energy in the U.S. faces a serious challenge: the lack of transmission. Clean Line's direct current (DC) projects will deliver thousands of megawatts of renewable energy from the windiest and solar-rich areas of the United States to communities and cities that lack access to new, low-cost, clean power. Read more about HVDC and how it works.
Wind is air in motion caused by natural factors like the uneven heating of the earth's surface by the sun, the rotation of the earth and the irregularities of the earth's surface. Wind energy has been used for centuries to move ships, pump water and grind grain. In the twentieth century, windmills were commonly used across the Great Plains to pump water and to generate electricity.
Wind turbines that are typically 200 feet or more above ground are used to harness the wind and turn it into energy. When the wind blows, it turns the turbines blades. The blades are connected to a drive shaft that moves with the blades. The shaft is attached to a generator, which creates electricity. The electricity created is in the form alternating current.
Watch this video by the Department of Energy about how wind turbines work.
In 2010, wind turbines in the United States generated about 2% of total U.S. electricity generation, equal to the annual electricity use of 8.7 million homes. Wind power represented 25% of all new U.S. electric generation capacity in 2010. Wind turbines do not release emissions that pollute the air and they do not require water for cooling. Not only does wind power provide a clean source of electricity, it helps keep electric rates low and protects consumers against fossil fuel price volatility.
Most renewable energy comes either directly or indirectly from the sun. Solar energy can be used for generating electricity, and for hot water heating and solar cooling. Solar energy is produced when the sun is shining during the day and is complementary to wind energy, which tends to reach its highest production at night.
Concentrated solar power uses mirrors to reflect and concentrate sunlight onto receivers that collect the solar energy and convert it to heat. This thermal energy can then be used to produce electricity via a steam turbine or heat engine driving a generator.
Watch this video by the Department of Energy on concentrating solar power.
Photovoltaic solar technology uses photovoltaic cells (PV) to convert sunlight directly into electricity. PV cells are made of semiconductors and can provide large amounts of power for the electric grid.
Watch this video by the Department of Energy on solar photovoltaic systems.
Using solar energy produces no air or water pollution and no greenhouse gases. Solar energy is predictable and is most efficient when utility rates are the highest.