Monday, November 24, 2008
Clean Solar Energy
Solar, wind, geothermal, plant matter, limitless resources. These are solutions ready now. The earth receives huge amounts of energy from the sun. Photovoltaics not discovered until the 20th century, but solar thermal technology has been used for thousands of years. Indians designed their buildings to face the sun. It's still a common design today. The Greeks laid out buildings to take advantage of sun during the winter, and hide them during the summer. The 19th century equivalent was the rooftop solar water heater. 30% of the homes in Pasadena used solar water heaters. This provides cheap hot water to millions. Heating water is the #1 user of natural gas energy. These don't use photovoltaic panels. Mirrors reflect the sun to concentrate. Never put your hand at the focus of a concentrated mirror. In hot dry areas, solarthermal plants create energy at prices typically lower than conventional grid power. Photovoltaic technology is surging ahead. Photons can be converted to electricity, said Albert Einstein. The first satellites' transistors went dead right away, then we switched to solar power. Our lifestyle is completely dependent on solar energy. The US Coast Guard powers its buoys with solar panels. One of the most valuable applications of photovoltaics is to provide drinking water to the rural poor. The most successful solar project is in Germany where there is less sunlight than in Seattle. The payback can be as little as 4-5 years. Rather than silicon, nanosolar. You use copper CIGSS. It absorbs sunlight readily so you can use very thin wafers. The foil moves slowly.