In discussions about alternative power, the term “base load power” often comes up. Base load power refers to power generation sources that are always available, 24 hours a day. These power supplies are not dependent on environmental factors to generate electricity. At the current time, there are three commonly available sources of base load power: coal-fired power-plants, nuclear power plants, and hydroelectric sources. All three of these power plant types have their own set of problems when viewed from an environmental standpoint.
Coal-fired power plants supply over half of the power generated in north America, with come well-equipped with a host of environmental woes. First there is the mining of coal, typically in large strip mines, or, in some places, by leveling the tops of mountains and filling in the valleys below. Of course, burning coal generates much of the world’s air pollution, including acid rain and greenhouse gases. What many people don’t know is that the burning of coal also liberates a large amount of radioactive material into the atmosphere, from radioactive isotopes of coal. In fact, coal-fired plants release far more radioactivity than do nuclear plants.
Another major issue with coal is that it is a fossil fuel. While it may be currently abundant, no more is being made. The resource is finite, and easily-accessible reserves are getting harder to find. This will eventually lead to greater and greater environmental damage as more of the landscape is stripped to provide power for homes and industry. So-called clean coal is burned more efficiently, and has cleaner exhaust, but it still faces the other problems.
Another source of base load power is the hydroelectric dam (http://ga.water.usgs.gov/edu/hyhowworks.html). Once built, hydroelectric dams are essentially powered by weather and gravity, and is often thought of as “green” power. However, the environmental costs of dam construction can be very high. A typical dam can flood thousands of acres of land behind it, destroying habitats. Wood and vegetation covered by water can rot, releasing methane and carbon dioxide, while the flooded land can release mercury and other poisons into the water, affecting fish, wildlife, and potentially human beings.
The last commonly-used source of base load power is nuclear. Nuclear has some very clear advantages and disadvantages. The disadvantage side is big, with storage and disposal of long-term nuclear waste being a major problem. Also on the down-side, there is the potential for disaster in the case of a leak or meltdown of the reactor itself. Then there is the public perception of nuclear power, and the conflating of it with nuclear weapons. There are technical solutions for the first two, including new reactor types, but the third requires time and education. The mining and production of nuclear fuel is also problematic, with uranium processing producing some incredibly toxic materials.
On the plus side, nuclear reactors produce no greenhouse gases. The mining of uranium is also markedly safer than coal mining. A properly-built reactor could be built practically anywhere, save in flood-prone areas or earthquake zones.
At this point, none of the commonly cited alternative energy resources are consistent enough to provide base load power. Wind and solar depend on environmental factors, including the availability of sunlight. Geothermal is very location specific, even more so than hydropower.
Space-based solar power could provide base load capability, as could Ocean Thermal Energy Conversion. Until those technologies bear fruit, the big three are essential to our industrialized society, and we have to make some choices as we move forward.