Solar power is the technology that converts energy from sunlight into electric power. It is renewable, clean, and limited only by the current state of our technology. According to the National Renewable Energy Laboratory, Germany, Spain, and Japan lead the world in photovoltaic solar power production. In the U.S., California makes and consumes the most solar power.
Kinds of Solar Power
Solar power is usually generated one of two ways, either using photovoltaic cells or using concentrating solar power technology. Photovoltaic cells use the "photoelectric effect." The cells absorb photons and release electrons. More precisely, light strikes the solar cell and knocks electrons loose from the atoms in the semiconductor material. The electrons are captured and channeled into an electric current. Concentrating solar power, on the other hand, uses the heat of the sun. This process heats water by collecting sunlight over a wide area and focusing it to a point with reflectors or lenses. This process is very similar to most conventional power generation stations. These stations heat water, which powers a steam-turbine generator, which generates electricity. The difference conventional power stations and a concentrating solar station lies in how the water is heated. Instead of using a fuel such as petroleum, coal, or nuclear energy, concentrating solar power uses the sun.
Solar Power Today
Solar power is in a period of unprecedented growth. The price of solar power continues to fall as production and efficiency rises. In the ten years between 1998 and 2008 the global average price of a photovoltaic module dropped 23 percent. Production of photovoltaic modules and cells experienced a 10-year compound annual growth rate of 46 percent during the same period. China, especially, has experienced very high growth rates. In June of 2010, SunPower announced a far more efficient solar cell, the most efficient on record to day. This new cell has a 24.2 percent efficiency.
Solar Power Tomorrow
The European Union has big plans for solar power. By 2015 these countries hope to have built a giant photovoltaic farm in the Sahara Desert. The Sahara has lots of open space and lots of sun. If only 1 percent of the Sahara Desert were covered with solar panels, those panels would generate enough electricity for the entire world. The possibility is enticing, but the problem of getting electricity from such a remote region to the people who need it is daunting. The European Union is working on that problem and hopes that by 2050, Europe's electricity needs can be completely satisfied by solar panels in the Sahara Desert.
Challenges to Solar Power
One of the biggest challenges to large-scale solar power plants is that the locations with the most sun, desert regions, tend to have the least water. Though photovoltaic farms work well in deserts, concentrating solar power plants need a lot of water to operate their generators and so do less well in desert regions. According to Senator Jon Kyl of Arizona, if all the commercial solar projects slated for Arizona in 2010 were actually built, they would require 151,720 acre-feet of water per year. That's enough water to supply 606,880 people, nearly a tenth the population of the state.
Solar Dreams
Some researchers believe that the way to overcome the problems of putting solar panels on the land is not to put them on the land at all but rather to put them in space. The MIT Space Solar Power Workshop is investigating what's involved in generating power for the earth using large photovoltaic satellites in orbit. The challenge is both finding a way of transmitting the collected power to the earth and finding a financially viable way of getting the collectors into orbit. The rewards, however, include never having to worry about clouds or weather.
Member Comments