Ending Our Dependence On Foreign Oil With Solar Power
Written by Neal Babcock
It seems that high prices for gasoline and heating oil used in homes are here to stay. Sure, they go up and down, but overall they still remain pretty high and consume more of our pocketbooks than they ever have in the past. We are constantly struggling with the Middle East, at least in part to protect our interest in their oil. And as other nations, including China and India, increase their demand for fossil fuels, it seems that conflicts regarding energy are looming large on the horizon. In the meantime, power plants that burn fossil fuels, as well as all of our vehicles everywhere, continue to pour millions of tons of pollutants into the atmosphere annually, threatening our health and well-being.
There are a number of well-meaning scientists, engineers and politicians who have presented various methods that could slightly reduce our use of fossil fuel. However, these steps are not enough. The US needs a plan to work itself away from our dependence on fossil fuels. It appears that only answer is a transition to solar power.
The potential of solar energy is overwhelming. For example, the energy in the sunlight striking the earth for only 40 minutes is equivalent to our human global energy consumption for one year. The U.S. is lucky in the sense that we have at least 250,000 mi. of land in the Southwest alone that is suitable for building solar power plants. That land receives more than 4500 quadrillion British thermal units (BTUs) of solar radiation every year. If we were to convert only 2.5% of that radiation into electricity, we would match the nation’s total energy consumption of 2006.
However, to convert this solar power, large tracts of land would have to be covered with photovoltaic cells and perhaps solar heating troughs.
The good news is that the technology is nearly ready. Let’s look at photovoltaic farms.
In the last few years, the cost to produce photovoltaic cells and modules have really dropped pretty radically, opening the way for large-scale implementation. A number of cell types exist, but the best modules today are made of very thin films of cadmium telluride. To work up the numbers, if we were to provide electricity at $.06 per kilowatt-hour by the year 2020, cadmium telluride modules must be able to convert electricity with at least 14% efficiency and complete systems would have to be installed at about a $1.20 per watt capacity. Current modules have only 10% efficiency and an installed system costs about $4 per watt. We are making progress, and the technology is advancing rapidly; commercial efficiencies have risen to upwards of 10% in the last year. As these commercial efficiencies rise, rooftop photovoltaic for the home will become even more cost competitive, further reducing daytime electricity demand on the utilities.
In one scenario, by 2050, photovoltaic technology could provide almost 3000 GW, or billions of Watts, of power. 30,000 square miles of photovoltaic arrays would need to be constructed. This may seem like a huge number, but current installations already in place show that the land required for each gigawatt hour of solar energy produced in the Southwest is less than the actual amount needed for a power plant when the area used for coal mining is taken into consideration. The National Renewable Energy Laboratory in Golden, Colorado shows that more than enough land in the Southwest is available without disturbing any environmentally sensitive areas, cities or towns. In Arizona, the Department of Water Conservation has stated that more than 80% of the state’s land is not privately owned and that Arizona is very interested in developing its solar potential. Because of the nature of photovoltaic plants, and the lack of water required to operate these plants, the environmental impact should be minimal.
The main problem is still reaching that magic number of module efficiency of 14%. Although the efficiencies of commercial modules won’t reach those of solar cells in the laboratory, cadmium telluride cells at the National Renewable Energy Laboratory are now up to 16.5% and rising. At least one manufacturer, First Solar in Perrysburg, Ohio, has increased the efficiency of their modules from 6% to 10% from 2005-2007. They plan on reaching 11.5% by 2010.
So, the trick is to keep an eye on the efficiencies of solar cells. After they reach 14% efficiency and the base cost per kilowatt hour becomes more acceptable, expect to see a number of companies and individuals making investments in this future.
