Sunday, August 24, 2008

Alternative Energy - Part 2 of 4 - A Look At Four Different Options

With the rise in the price of conventional fuels (namely oil and natural gas) earlier this year, there was a shift to look at different energy alternatives. Many people have pointed to the need for green energy, while others have talked about the U.S. dependency on foreign countries for oil. Whatever the reasons may be, alternative energy sources are going to become a growing part of our lives.

Today's post will be the second in a series of four posts discussing four different alternative energy sources - nuclear, solar, wind, and ethanol. As Joe Rollins discussed in his August 15th post "Energy Crisis Resolved!", all possible technologies should be reviewed. While none of these sources to be discussed are new, the importance of each over the next 10+ years should grow.

Solar Energy

Solar Energy has been around for decades, but many really do not know or understand the basics. Essentially, there are two ways to harness the sun's energy - solar thermal and photovoltaics.

Solar thermal is the lessor known and lessor used solar energy option, and it is generally used to heat swimming pools and water in residential homes. Solar thermal is also being used commercially by extremely large power plants. A plant generating energy via solar thermal uses literally acres of mirrors to focus the rays to create steam to drive turbines to create power. One plant, Nevada Solar One, uses more than 300 acres of mirrors to generate power for 14,000 homes around Las Vegas. One report by the Energy Information Administration of the U.S. Department of Energy believes that solar thermal systems will grow 23% in 2008 over 2007.

The solar energy we all know about though is photovoltaics or "PV". PV uses silicon to create solar cells that energize electrons and generate electricity. They can be used in something like that solar calculator we all have, or something much, much larger - say a home or store.

Solar cells are being used more and more, and the main issue for them is efficiency. The space that each solar cell has is finite, but the efficiency in which it can create electricity is the catch. The only real problem for solar cells (in a region that can utilize them effectively) is the start-up costs. The cells are not cheap, but current government tax subsidies and a push for green power have helped some businesses (retailers specifically) to look at them seriously.

Earlier this year, Wal-Mart (WMT) announced a pilot program in which they were installing solar cells on the roofs of 22 stores (Sam's and Wal-Marts) to study the efficiencies. SunPower is the maker of the cell that Wal-Mart is testing. The proprietary "SunPower T-10" solar roof tile tilts at a 10-degree angle to increase energy capture, and it is claimed to be 50 percent more efficient than conventional solar panels. The savings to Wal-Mart started on Day One...

Wal-Mart is not alone though as Kohl's, Safeway, and Whole Foods Markets have started their own programs. While none of these have more than 10% of their stores set up for solar power generation, if Congress will continue the solar subsidies, it is believed the popularity of solar cells for retailers would increase.

As the technology improves, the current solar cells that only allow 15-22% of the solar energy to be converted into usable energy will be replaced by much more efficient systems. As they improve and costs drop, do not be surprised to see them popping up on residential roofs and store roofs alike. The projection is for the use of solar cells to jump 50% from 2007 to 2010.

Sources: U.S. Department of Energy, Reuters, Janus

1 comment:

Anonymous said...
This comment has been removed by a blog administrator.