- Hydropower (Figure25.19) uses the energy of moving water to turn turbines or water
wheels, which drive a mechanical mill or an electric generator. Today, the largest use
of hydropower is for electric power generation, which allows low cost energy to be used
at long distances from the water source. Electricity can also be generated constantly,
as long as sufficient water is available, it produces no primary waste or pollution, and
it is a renewable resource.
Figure 25.19: Small hydropower plant, Buchholz, Switzerland. ( 36 )Other alternative energy sources to the burning of fossil fuels includegeothermal power;
biomass, biofuels; tidal power;nuclear energy; andfusion power. Let’s examine these
briefly to see how they compare with the sources of energy we’ve already discussed. Keep in
mind as we do so what you think the best alternatives might be.
- Geothermal power uses the natural flow of heat from the earth’s core to produce steam,
which is used to drive turbines, which, in turn, power electric generators. - Biomass production involves using garbage or other renewable resources such as corn
or other vegetation to generate electricity. When garbage decomposes, the methane
produced is captured in pipes and burned to produce electricity. Advantages of these
types of energy include using organic waste products from agriculture; biomass is
abundant and is generally renewable. - Power can be extracted from Moon-gravity-powered tides by locating a water turbine
in a tidal current. The turbine can turn an electrical generator, or a gas compressor,
which can then store energy until needed (Figure25.20). - Nuclear power plants use nuclear fission to generate energy inside a nuclear reactor.
The released heat, heats water to create steam, which spins a turbine generator, pro-
ducing electricity (Figure25.21).