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Hydropower is likely to have no future on the Colorado
November 30, 2007
Shaun McKinnon of the Arizona Republic wrote a piece on November 24, 2007 about an overall reduction in the snow pack along the headwaters of the Colorado River--a consequence of climate change. According to government forecasters, a reduced snow pack is predicted through the winter and early spring. The article by McKinnon is linked here.
Contrary to popular perceptions, the production of hydropower from Colorado River dams is actually quite insignificant. For example, the coal-burning Navajo Generating Station near Lake Powell will produce more electricity annually than all the hydropower facilities on the Colorado River combined. Hydropower operations cannot run at maximum capacity on an annual basis. If they were operated in this manner, they would effectively drain the reservoirs in no time.
Another popular perception is that hydropower is utilized by a typical surburban household in metropolitan Phoenix, Las Vegas or Los Angeles. In reality, typical hydropower customers are irrigation projects, rural communities, and various government facilities. Click here to see a spreadsheet of hydropower customers.
Hydropower revenues are down significantly at the dams before the biggest reservoirs on the Colorado River, namely Lake Powell and Lake Mead. For example in early 2005, the efficiency of the power plant at Glen Canyon Dam was 60% of normal, which is about as efficient as a junk yard pick-up truck.
Both reservoirs are presently half-full, which means there is not enough water in storage to provide the water pressure, or hydraulic head, necessary to spin the generators into dollars sufficient enough to be economically viable.
The loss of revenue due to the system's continuing inefficiency has required the re-negotiation of contracts with customers that use this subsidized federal power and, stifled the payback schedule (see spreadsheet) to the U.S. Treasury for the construction loans provided to build the water projects of the Colorado River basin.
Reservoirs may not necessarily emit carbon dioxide or methane at the power station, but greenhouse gas emissions do occur at the places where rivers and tributary streams dump their organic loads (leaf littler and driftwood) into the reservoir, where it begins to decay. This natural breakdown of organic materials affects altered river corridors in negative ways (Report).
For example, it depletes the oxygen levels at lower layers of the reservoir, which are called "dead zones," because fish can suffocate. Sometimes this layer of depleted oxygen actually passes through the turbines and into the Colorado River below the dams.
Besides emitting carbon dioxide and methane gas into the atmosphere, the decay process also produces hydrogen sulfide, which is corrosive and foul-smelling.
In fact, when weather conditions are favorable, I have observed the upper reservoir fizz like a carbonated drink, and with matches have ignited the bubbling vents of methane on the exposed mud deposits. Click here to see photos of a methane gas vent at Lake Powell in 2005 ("mud volcano").
A discussion of greenhouse gases from reservoirs can be read by clicking here.
To learn more about the science of limnology click here.
Along with the organic detritus, sediment is also deposited into the reservoir's river arms and tributary canyons. These sediment deposits are currently perched above the current level of the reservoirs. They are massive and over 30 miles in length along the main stem river arms.
They are anything but clean: when it rains, the deposits turn into thick, gooey mud. When the weather is dry and windy, dust fills the sky. The tumbleweeds and salt cedar grow so thickly that camping, and hiking opportunities into side canyons, are usually impossible.
In fact, hydropower on the Colorado River may never work efficiently again, since Colorado River water managers are allowing the demand for water to match, and even exceed, the supply, which is all the more exacerbated by this persistent drought and the looming impacts of a warming global atmosphere.
2011 - Testimony by Leslie James. CREDA.
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