6 Solar technologies to power the world

Solar trees The Stirling dish is a 30-year-old technology that's just now becoming cost-effective thanks to big solar-power orders from utilities. In time, 70,000 of these "solar trees" planted in the Mojave Desert by Stirling Energy Systems of Phoenix could power a million homes. Distributed power tower What happens if the sun's not shining? Bright Source Energy has a solution called a distributed power tower: Mirrors focus the sun's rays on a boiler, creating steam which drives a generator. Natural gas can be used to power the plant when the sun isn't shining.

Heliostat concentrator

In southeastern Australia, Solar Systems will build a heliostat concentrator photovoltaic array of mirrors which focuses sunlight on high-efficiency solar cells to produce electricity. Microdishes GreenVolts, a San Francisco startup, is building arrays of microdishes - dinner-plate-sized mirrors that concentrate the the sun on an efficient solar cell. Small clusters of these microdishes are compact enough to be installed near cities, plugging directly into the grid to relieve overloaded substations.

Ground-mounted tracking photovoltaic

Utilty-scale solar refers to any solar installation large enough to replace conventional power plants. This solar station outside the village of Serpa, Portugal, was built by PowerLight of Berkeley, Calif. It covers 150 acres and powers 8,000 homes.

Solar trough

In California's Mojave Desert, parabolic mirrors heat tubes of synthetic oil, which in turn produce steam to drive electricity-generating turbines in an arrangement that's known as a solar trough. Built by Luz in the 1980s, the solar plants continue to power 150,000 homes. Now solar-trough technology is drawing interest again. Acciona Solar Power has built a 64-megawatt plant in Nevada. Full Story @ http://money.cnn.com/magazines/business2/business2_archive/2007/06/01/100050990/index.htm