The Practical Science Behind Solar Cells

Recent breakthroughs promise to dramatically improve the output of solar cells. Scientists at MIT have developed a new solar cell that increases power by a "factor of over 40". The technology employs "organic solar concentrators" to increase power conversion. Nobel Prize winner Alan Heeger, Professor of Physics who teaches in the University of California system, announced in March 2008 that his team had improved solar cell efficiency by 5.1 percent. Their technique employs alkanedithiols as an agent.

Aside from the latest advances in the technology, there are practical issues of using solar cells. How many cells are typically used on a house? How many cells are needed to power a home? According to Rochester Solar Technologies, "A typical 2Kw or 2000 watt system which consists of 12 solar modules will typically generate 2000Kwh's of electric per year with some variables."

What are the disadvantages of solar panels? First, they do not work when covered with snow! When it snows, it is necessary to carefully clear the snow from the panel. To some extent, placing the panels on the side of the house instead of on the roof can alleviate this disadvantage. Still, it is important to consider how the system will function during an ice storm; keeping a fireplace, a backup propane system, and candles is wise.

Another practical issue of using solar panels is the cost. Can money be saved by building solar panels or by purchasing a kit and installing the panels? As with any amateur project, there is a certain amount of trial and error, but the World Wide Web is full of enthusiastic hobbyists. Some of them have pictures of homemade solar cells.

Another consideration is Moore's Law, which holds that semiconductor size will continue to decrease substantially, at least for the near future. That means that future computers will require less energy, so the homes that house them will require less energy. Required solar panel output should also be lower.

Beyond the immediately practical issues, the reduction in damage to the environment is enormous. According to Rochester Solar Technologies:

"Over its 35-year expected life, a 10 kW system will provide the equivalent CO2 reduction as planting 1450 trees. (Based on typical utility pollution, it will prevent emissions of 963,125 lbs of carbon dioxide, 4,237 lbs of sulfur dioxide, and 1,364 lbs of nitrogen oxides.) It will produce 575,000 kilowatt hours of electricity, as much as would be generated by burning 583,000 lbs of coal."

The new technologies promise a brighter, cleaner tomorrow.