How does solar power work?
Hameed Naseem, professor of electrical engineering in the College of Engineering, replies:
Solar energy is harnessed to produce electrical power by using solar cells. A solar cell absorbs light to produce electron-hole pairs, and separates negatively charged electrons from positively charged holes, thereby generating an electrical potential. Individual cells generate less than a volt of potential but a large number of such cells connected in series and parallel in a solar module produce the desired voltage to drive any electrical device. Solar modules typically convert about 10-15 percent of the free solar energy into useful electrical energy without emitting any environmentally hazardous by-products. Silicon, the most abundant and benign element found on earth, is the material of choice for these solar cells. A 30-square meter solar array produces about 800 kW-hours of electrical energy per month. That is sufficient to provide all the electrical needs of a typical family with some left over to be sold back to utility companies. Because of the problems of global warming and the limited supply of fossil resources, future energy resources are expected to be sustainable and renewable. In the Energy Technology Roadmap for 2030, solar power is slated to contribute more than 50 percent of the world energy needs. The United States receives, from the sun, about 10,000 times our current annual use of electricity.
Since sunlight intensity changes with the time of the day and is unavailable at night and under rainy or cloudy conditions, a solar power system is comprised of not only the solar array, but also a bank of batteries, charge controllers and inverters.