Environmental Engineering Reference
In-Depth Information
Figure 1.1
A large coal-fired steam-electric power plant whose electrical power output is nearly 3000
megawatts. In the center is the power house and tall stacks that disperse the flue gas. To the left, a cooling
tower provides cool water for condensing the steam from the turbines. To the right, high-voltage
transmission lines send the electric power to consumers. (By permission of Brian Hayes.)
direct contact with the reactor fuel elements. The main disadvantage of a nuclear power plant, which
does not release any ordinary pollutants to the air, is the difficulty of assuring that the immense
radioactivity of its fuel is never allowed to escape by accident. Nuclear power plant technology is
technically quite complex and expensive. The environmental problems associated with preparing
the nuclear fuel and sequestering the spent fuel have become very difficult and expensive to manage.
In the United States, all of these problems make new nuclear power plants more expensive than
new fossil fuel power plants.
Renewable energy sources are of several kinds. Wind turbines and ocean wave energy systems
convert the energy of the wind and ocean waves that stream past the power plant to electrical power.
Hydropower and ocean tidal power plants convert the gravitational energy of dammed up water to
electrical power (see Figure 1.2). Geothermal and ocean thermal power plants make use of a stream
of hot or cold fluid to generate electric power in a steam power plant. A solar thermal power plant
absorbs sunlight to heat steam in a power cycle. Photovoltaic systems create electricity by direct
absorption of solar radiation on a semiconductor surface. Biomass-fueled power plants directly
burn biomass in a steam boiler or utilize a synthetic fuel made from biomass. Most of these energy
systems experience low-energy flux intensity, so that large structures are required per unit of power
