Over half of renewable energy goes to producing electricity.
The first practical photovoltaic (PV) cell was developed in 1954 by Bell Telephone researchers examining the sensitivity of a properly prepared silicon wafer to sunlight. Beginning in the late 1950s, PV cells were used to power U.S. space satellites.
Covering 4% of the world's desert area with photovoltaics could supply the equivalent of all of the world's electricity. The Gobi Desert alone could supply almost all of the world's total electricity demand.
The world's largest wind farm, the Horse Hollow Wind Energy Center in Texas, has 421 wind turbines that generate enough electricity to power 220,000 homes per year.
In 2011, wind turbines in the United States generated about 3% of total U.S. electricity generation. Although this is a small fraction of the Nation's total electricity production, it was equal to the annual electricity use of about 10 million households.
A typical horizontal wind machine stands as tall as a 20-story building and has three blades that span 200 feet across. At the tip of the blades, they're moving over 200 mph. This means high efficiency and low torque which contribute to good reliability. Some models operate at constant speed, but more energy can be collected by variable-speed turbines.
In 2011, consumption of renewable sources in the United States totaled about 9 quadrillion Btu or about 9% of all energy used nationally. About 13% of U.S. electricity was generated from renewable sources in 2011.
Nine solar power plants, in three locations in California's Mojave Desert, comprise the Solar Energy Generating Systems (SEGS). SEGS VIII and IX (each 80 megawatts), located in Harper Lake, are, individually and collectively, the largest solar thermal power generating plants in the world. The SEGS plants are concentrating solar thermal plants.
Generation from wind in the United States increased from about 6 billion kilowatthours in 2000 to about 120 billion kilowatthours in 2011.