Electric power produced by direct sunlight isn’t the norm, but it can be done. Photovoltaic cells composed of thin sheets of silicon and the semi-conductor metals cadmium and gallium, when exposed to sunlight, generate an electric current. On the plus side, it’s the cleanest source of electricity available. Why isn’t it used more? One reason is cost – solar electric generation is several times more expensive than fossil fuel-based power production (the numbers I’ve found, which are about five years old, indicate that solar power costs three to five times as much as coal-fired power to produce). And while solar power in the form of sunlight is the most abundant energy resource on Earth, the energy is dissipated, and must be concentrated before it can be used. Additionally, the distribution of solar energy worldwide is uneven. It’s strongest at the equator, and weaker in higher latitudes. It’s variable seasonally as well as over the course of a day, and completely absent at night (which near the equator, is 12 hours out of every 24). Solar photovoltaic cells are inefficient compared to other types of energy, and the linked solar cells require hundreds of square acres of land. So while solar-powered electric generation exists, it’s not liable to become widespread as long as fossil-fuels are relatively cheap and easy to use.
Part of our difficulty in using solar power is our Western mindset. In industrialized nations we tend to think big. We as a society tend to think in terms of huge power grids, and ever larger amounts of kilowatts generated supplying increasingly more populated areas. But the greatest strength of solar power is the cumulative total of multiple small-scale uses, providing individual households with hot water and cooking meals. In this arena, solar power has been used with considerable success in countries like Greece and Italy. Individual roof-top solar units provide about 83% of the hot water needs of Israel, a country with little fossil fuel resources. Simple, low-cost solar-powered cookers are used by backpackers and are becoming more common in wood-poor countries, where gathering fuel for cooking fires can consume up to half a day.
