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>Solar Panels


There’s nothing new about solar house panels. They can be used to heat water for the pool or water heater. The cost for our home, some $4,000, has delayed our installation, but maybe it’s not so bad.

By the time we get ready, something new that has been invented will save us a lot of money–or at least be more efficient.

Solar rising
As a result of the oil crises of the 1970s, alternative energy sources, including solar power, received increased attention. From the mid-1970s through the mid-1980s, the solar industry grew from 45 solar collector manufacturing firms to 225 firms, according to the U.S. Energy Information Administration (EIA). During this period, construction began on nine solar thermal power plants, collectively referred to as the Solar Energy Generating Systems (SEGS), in California’s Mojave Desert. These power plants — still the largest solar plant system in the world — were hybrids, using solar energy by day but fossil fuels at night.

In the late 1980s, oil prices fell and remained low through the 1990s — and construction of new solar plants stalled. But more recently, with oil prices soaring past $130 per barrel, solar power has once again become economically attractive. In the United States, the solar energy industry has been growing rapidly since 2003, fueled not only by high energy prices but also by an increased focus on reducing carbon emissions.

They can do it today with mirrors. Some people are familiar with photovoltaic cells. These cells convert sunlight to electricity by absorbing photons from the sun’s rays; the photons kick some electrons loose from atoms of silicon in the cells, and the resulting flow of electrons through the material produces electricity.

Above photo Courtesy of DOE/NREL, Credit – Dave Parsons

The Jefferson County jail in Golden, Colo., uses a parabolic trough solar thermal system to provide hot water to the facility, meeting 50 percent of its hot water needs.

In addition to providing electricity, hot water and heat to homes and businesses, photovoltaic systems supply power to everything from ocean weather buoys and communications equipment to streetlights and satellites.

But cost is an issue: Photovoltaic solar power is still more expensive than electricity generated by fossil fuels, costing between 10 and 40 cents per kilowatt hour, depending on whether it comes from a solar power plant or from cells on a small building. Coal, on the other hand, costs 2 to 4 cents per kilowatt hour.

An innovation to temporarily store the heat, improves on one of solar energy’s primary limitations — sunlight is intermittent. A few plants use insulated tanks filled with molten salt for heat storage, which — although only possible for a few hours — means the plant can still provide power on cloudy days or at night.

See Carolyn Gramling’s article at GEOTIMES