Cincinnatus BLOG *** Political Commentary - Social Commentary

Hydroelectricity is the most widely used form of clean renewable energy in the world, generating over 19% of the world’s electricity. It requires no fuel and produces no direct emissions or by-products. The United Nations estimates that the technically exploitable potential for hydropower is 15 trillion kilowatt-hours per year, amounting to half of the total projected global electricity needed in 2030. In the United States, hydropower has fallen to 10% of the electricity supply mix down from14%, 20 years ago. In terms of electricity production, hydropower accounts for only 7% of America’s current power needs.

Source US Department of Energy

In theory, the mechanics of a hydropower plant are simple, build a dam on a large river that has a high elevation; gravity causes the water to flow through the dam, which turns the turbine, which then turns a generator. The force of the falling water produces hydroelectric energy. The capacity to produce this energy is dependent on both the available flow and the height from which the water falls.

Potential energy accumulates as water builds up behind a dam. This is transformed into mechanical energy when the water rushes down the sluice and strikes the rotary blades of a turbine. The turbine’s rotation spins electromagnets, which generate current in stationary coils of wire. Finally, the current is put through a transformer where the voltage is increased for long distance transmission over power lines.

Another potential way to use hydropower is as a large “battery” for other clean sources of energy. The process is called “Pumped Storage“. Such facilities already exit - water is pumped from a lower reservoir to higher reservoir using electricity generated from another source. When additional power is needed the water is released back into the lower reservoir through the turbines. Although some power will be lost, perhaps 20%, integrating wind or solar with “Pumped Storage” hydropower, could provide a “battery” for the storage of the excess energy created in high wind periods or on sunny days. Given the obvious limitations of traditional batteries this may be a viable way to deal with the intermittency of wind and solar power.

Though costly to build, the technology is reliable, and has been proven over time. In addition, unlike most other renewable energy sources hydroelectric plants have low operating and maintenance costs making its possible to provide relatively inexpensive power. Thus, at first glance, it would appear that hydropower; a proven source of clean renewable energy could be a major contributor to our future electricity needs. Environmental groups however, have blocked virtually all-major projects in the last 30 years arguing successfully that blocking rivers with massive dams produces habitat destruction, prevents passage of fish and displaces local communities.

The Department of energy despite recognizing the advantages of hydropower has essentially adopted the position of the environmental groups.

In their monthly report issued January 15, 2009 the Energy Information Administration of the Department of Energy has the following commentary on hydroelectric power: “Water is currently the leading renewable energy source used by electric utilities to generate electric power. Hydroelectric plants operate where suitable waterways are available; many of the best of these sites have already been developed. Generating electricity-using water has several advantages. The major advantage is that water is a source of cheap power. In addition, because there is no fuel combustion, there is little air pollution in comparison with fossil fuel plants and limited thermal pollution compared with nuclear plants. Like other energy sources, the use of water for generation has limitations, including environmental impacts caused by damming rivers and streams, which affects the habitats of the local plant, fish, and animal life.”

Unless there is a change in priorities hydroelectricity will be relegated to small-scale hydro plants that can generate electricity for a single community and essentially become irrelevant in the United States. One must raise the philosophical question: Have we become incapable of finding innovative ways of dealing with potential problems and taking advantage of our natural resources, or do we just say no to proven clean solutions?  And if we close the door to proven, inexpensive, high output clean technology will we ever significantly reduce our carbon footprint? Innovative solutions such as “Pumped Storage” batteries could make intermittent technologies such as solar and wind economically viable.