Though still small, contributors to the world’s electrical grid, wind, geothermal, biomass, solar, and fuel cell technologies. May represent the power of the future, given the economic, geopolitical, and environmental costs of power generation in operation today. Wind power has been used for centuries, but instead of turning millstones it now involves large, fanlike blades geared to turn turbines.
Farms, concentrated installations of power-generating wind turbines, have found their most extensive use in California. Wind power plants operate in northern Europe, Saudi Arabia, and India, and more have been proposed for the U.S., offshore on the Atlantic coast, and the midwestern plains.
Different Power-source options:
Geothermal systems tap Earth’s underground heat. Like sunlight, this is a free and limitless resource. But one that for large-scale use requires the user to be near an area where the volcanic activity or radioactive decay is producing heat close enough to the surface to be used efficiently. Single dwellings can benefit from geothermal
heat just by conscientious design. Biomass fuels are typically distilled from corn, sugarcane, or other plants high in sugar. They have recently gained popularity, but the local and global economic effects of redirecting agricultural production for fuel rather than food raises concerns. As does the number of fossil fuels used to grow such crops.
Solar energy reaches Earth at a rate of about 200,000 times the daily capacity of existing power plants, and available technology harnesses it for heat or electricity. Solar panels work by absorbing heat from the sun and transferring it into circulating fluid. Photovoltaic cells made of silicon, boron, and other substances
convert sunlight into electricity. As with geothermal energy, individual buildings can be designed to benefit from the sun’s heat without complex equipment. A technique called passive solar.
Fuel cell technologies hold great promise. Research agencies, private companies, and the world’s major automobile manufacturers are exploring these new ways of converting chemical energy directly to electricity, possibly providing a battery-operated alternative to the conventional automobile.