Energy Perspective: Is Hydroelectricity Green?.

Introduction The current worldwide concern over energy is primarily related to imported oil, oil drilling and refining capacity, and transportation capacity. However, this concern has bolstered interest in a broader range of "green" energy technologies. Concern over the environment is well founded. The Environmental Protection Agency's Office of Air Quality Planning and Standards (1998) estimates that by 2010, electrical generators in the United States will dump 182,968 tons of particulate air pollution per year. These pollutants include mercury, lead, arsenic, hydrogen chloride, and many more carcinogens and toxins that cause lung cancer, asthma, and other diseases, and degrade flora and fauna. Also released is carbon dioxide, the primary greenhouse gas. Are you thinking that air pollution will be reduced significantly once the United States switches to electric vehicles? Guess again. There may be a reduction in air pollution in busy locations, but its significance remains to be seen. China uses coal extensively to generate electricity, and the United States also uses large quantities of coal for electrical power generation. In the future when your electric car runs out of electricity, you will plug it in to a convenience outlet at home, school, or work, and you will essentially be running your automobile on coal, natural gas, petroleum, or nuclear energy sources, all of which have major problems associated with them, and all of which are the main energy sources for generating electricity in the United States. [FIGURE 1-A OMITTED] Concern over imported energy in the United States is well founded. Some natural gas is imported, and natural gas accounts for 40 percent of the United States' electrical-generating capacity. Petroleum accounts for 6 percent of electrical-generating capacity. Coal and nuclear are major contributors to electrical generation also (Energy Information Administration, 2007). Coal accounts for almost all of the air pollution associated with electrical generation (Office of Air Quality Planning and Standards, 1998), and no one knows with great certainty how to safely store radioactive waste from nuclear power plants to the extent that humans and the environment will be protected one thousand years from now when that same waste will still be radioactive. Could hydroelectricity be part of the solution? Hydroelectricity Hydroelectricity is similar to nuclear electricity in that there are very few airborne pollutants that result from the generating process during normal operation. Nuclear power accounts for slightly more of the United States' generating capacity than hydroelectric. There are currently 3,988 hydroelectric generating units in the United States--23.5 percent of all generating units. However, that only represents 7.7 percent of the electricity generated annually (Energy Information Administration, 2007). There is obviously a practical disadvantage to depending on hydroelectricity; these power plants are not always able to operate if the water supply is low. [FIGURE 1 OMITTED] Why Fuels Are Needed to Generate Electricity Electromagnetic induction is a phenomenon by which electrical current can be made to flow in an electrical conductor. Copper wire is an example of an electrical conductor, and at the atomic level, copper has an extra electron in its outer shell. When that electron is caused to move from one copper atom to another, you have electrical current or the flow of electricity. Electrons in neighboring atoms are behaving the same way, so you end up with current flowing in all parts of the conductor. What can cause the electron to move from one atom to another? Magnetism. In order to induce current flow in a conductor, there must be relative motion between the conductor and the magnetic field. No matter what the source of energy used to generate useable electrical current from electromagnetic induction, the process is basically the same--move an electrical conductor in a magnetic field or move a magnetic field across an electrical conductor. …