In 2002, the following amount of electricity, in gigawatt-hours, was generated from the following sources of fuel:
Coal: 1,925,792 GWh
Nuclear: 779,461 GWh
Gas: 695,226 GWh
Hydro: 255,077 GWh
Fuel oil: 91,629 GWh
Biomass: 71,534 GWh
Other (geothermal, non-wood waste, wind and solar): 22,737 GWh
According to the American Solar Energy Society, enough sunlight falls on the earth's surface each minute to meet world energy demand for an entire year.
Replacing an electric water heater with a solar model can reduce water heat costs by 50 to 80 percent every year - and over the 20-year life of the equipment, more than 50 tons of carbon dioxide emissions will be displaced.
The altitude of the sun varies throughout the year. On December 21st (sometimes the 22nd) the sun is 20 degrees above the horizon, it's lowest point of the year. On June 21st (sometimes the 20th) the sun is 65 degrees above the horizon, it's highest point of the year.
Do you know what days these are? They are the winter & summer solstice.
The company SunPower in 2008 announced 22% efficiency converting light to electricity. Current high-performance panels, on average, convert about 20 percent of the light that strikes it into electricity. Conventional silicon solar panels convert about 14 to 17 percent of light.
The theoretical maximum is around 26 to 27 percent, although some have said it could go slightly higher.