All the energy the earth has ever seen has come from one source, The Sun. To this day the sun gives us
all the energy we could ever need, we are using solar energy from millions of years ago in our daily
lives. Oil is stored solar energy. Coal is stored solar energy. Wood is stored solar energy. Wind is a form
of solar energy.
Solar electricity was first discovered in the early 1870's when it was noticed the resistance in Selenium
decreased when exposed to light. This experiment yielded photoelectricity at about 1% efficient. In
the early 1950's Bell Labs conducted experiments with silicon and yielded around 4% efficiency. Solar
cells started to power satellites in the 1950's. Today the best solar cells are achieving efficiencies near
20%, with complete panels near 17%.
What does that mean? Well on a clear day, near the equator, at solar noon, with little atmospheric
pollution the sun delivers 1kW/m2, or 170 Watts per square meter in the form of electricity or approximately 600 Watts
in the form of heat with solar thermal. One hour of sun would run 10 - 17 Watt compact flourescent light bulbs for one hour.
Cover more area with solar panels and you get more energy
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