In Perspective - Hydro Power
The oldest type of full scale electrical production is hydro power. Hydro power has been around for centuries and has been found in all of the major civilizations. But it wasn’t until the late 1800's that the power of water has been used to create electricity. Now hydro power produces almost 20% of world electricity production. But with its age it is in the midst of a revolution.
The Recovery Act has assigned more than $30 million for infrastructure improvements for hydro power. This is only for seven generation stations and is expected to increase output by 187,000 MWh/year. It is estimated that efficiency improvements to U.S. power plants could add 10 to 15% more output without adding any more dams to our inventory. But this isn’t the only news in hydro power. New approaches are looking at tidal power, wave power as well as water flow power.
Tidal power is technically using the solar and lunar gravitational pull to generate power and is much more consistent than other renewable energy sources such as wind and solar. It is limited to coast lines and is more preferable in the higher latitudes that have large tidal changes. Tidal energy has an efficiency of 80% in converting the potential energy of the water into electricity which is much higher than burning of fossil fuels or nuclear.
Water flow technology is very similar to tidal power and does cross into that realm. Water flow uses turbines positioned into water flow to tap the energy of the water movement. These are more versatile than tidal power devices but have smaller output per device. They can be placed in rivers as well as using tidal flow. Water turbines also fall into this category. Water turbines are small generating devices that can be placed in small rivers and streams with a small drop in water called head. These are already very popular in third world countries and remote areas with water flow.
Wave power generation is the capture of energy from ocean waves. Again, location is important as well as consistency of wave production. Most of the wave power generation technologies are still in the trial stage of development but do show promise.
There are some pitfalls to hydro power. The most obvious is the lack of water, while another is too much water. A prime example of lack of water is America’s largest reservoir, Lake Mead created by the Hoover dam on the Colorado River. In the last ten years Lake Mead has lost 50% of its water storage. There is some that give Lake Mead a 50-50 chance of drying up by 2021. Right now the Hoover produces enough power to light a half a million homes and pump water to a large portion of southern California. The lake also provides drinking water and irrigation for a half dozen states. Losing the lake will affect millions of people as well as costing billions in lost revenue.
The American Society of Civil Engineers gives American infrastructure an average of a D which includes 80,000 dams with a rating of D. About 3,500 dams are deemed unsafe; some are classified as on the verge of collapse. The Wolf Creek dam in Kentucky is a primary example. In recent years the water level has been reduced as workers are patching leaks around the clock trying to keep the dam from failing. The dam holds the largest reservoir east of the Mississippi River and is less than 50 miles from Nashville. The big worry is a large influx of water from flooding rains would force the collapse of the dam and flood the valley below. Nashville could expect 20 feet of water in its downtown area and put in jeopardy thousands of lives and billions of dollars in damages.
http://www.youtube.com/watch?v=2gn5nTyUXbc
http://www.yourhendersonville.com/wolfcreek.html
http://www.mywindpowersystem.com/2009/08/alternative-energy-the-facts-tidal-energy-part-5/