Solar	Wind	Biomass	Geothermal	General

SOLAR Solar Energy Available Every day, more energy falls on the U.S. than we use in an entire year. The total amount of solar energy per year falling on the conterminous 48 states is 1.37 * 1016 kW-h/year - or 46,700 Quads/year - of solar energy falling on the lower 48 states. Compare this to 94.2 Quad/year, the rate of energy consumption in the U.S.in 1997 ( Ref: Renewable Energy Annual 1998, DOE/IEA-0603(98), pg 1.) Every day more solar energy falls to the Earth than the total amount of energy the planet's 5.9 billion inhabitants would consume in 27 years (http://www.nrel.gov/learning/re_solar.html.) Use the UV index to estimate solar energy: Multiply the UV index (1-10) by 100 to roughly estimate the peak solar energy (usually around noon) in Watts per square meter for the day (i.e., UVI = 9 => 900 W/m2 around noon) Multiply the UV index by 5 to roughly estimate (around noon) the peak number of Watts per square meter of solar energy in the UV part of the spectrum (wavelength < 400 nm)

WIND U.S. wind potential Researchers estimate that there is enough wind potential in the United States to displace at least 45 quads of primary energy annually used to generate electricity. California wind energy More than 16,000 wind turbines in California generate enough electricity to meet the residential requirements of a city of about 1 million people (The population of Denver is about 500,000). This is equivalent to a medium-sized nuclear plant (http://www.nrel.gov/wind/atlpap2.html.)

BIOMASS Biomass energy use in the U. S. Today, various forms of biomass energy account for 45 percent of renewable energy used in the U.S. Biomass is used to meet a variety of energy needs, including generating electricity, heating homes, fueling vehicles and industry (http://www.nrel.gov/learning/re_biomass.html.)

GEOTHERMAL U.S. geothermal power production U.S. geothermal power plants generate enough electricity to power the homes of more than 3.5 million people. The power plants produce electricity at 5¢ to 7.5¢ per kilowatt-hour (http://www.nrel.gov/learning/re_geothermal.html.)

GENERAL What is a kilowatt-hour? Burn a 100 Watt light bulb for 10 hours and you have consumed 1000 Watt-hours, or 1 kilowatt hour of electricity. Mowing the yard with a 5 horsepower (hp) lawnmower for 15 minutes is about equal to a kilowatt hour of energy production (1 hp = 735 Watt = 0.735 kW.) Since motors and engines are not 100% (most are around 30%) efficient, the engines use more energy (about 3 times) than they produce. The lost energy goes into wasted heat. What is a quad? A "quad" is one quadrillion (1.0*1015) British Thermal Units (Btus.) 1 million (1.0*106) Btu = 90 pounds of coal or eight gallons of gasoline. So, one Quad is about equivalent to the energy in 45 million short tons of coal or 167 million barrels of crude oil. Our Energy Appetite Where does energy come from and where does it go? Check out DOE's Energy Information Agency (EIA) at http://www.eia.doe.gov/. EIA's Renewable Energy site is at http://www.eia.doe.gov/fuelrenewable.html. Data for the US can be found at http://www.eia.doe.gov/emeu/world/country/cntry_US.html The US produced 72 quads of energy, while consuming 92 quads in 1997. The difference (20% of our consumption) was imported.