Hydro Potential U.S.A.

Yesterday’s post made me aware that I’d never before mentioned hydro-electric power on this blog before, although it interests me a great deal. As mentioned, we obtain 6 percent of our electric power from hydro plants. I got to wondering how many such plants we have—and whether or not a nice map may be available. Thanks to the Department of Energy, I found this wondrous map here.

The map shows all existing hydro-power plants as little yellow squares. The legend, which shows areas (in purple) unsuitable for hydro power because of federal laws or policies prohibit such facilities, also shows areas which have a potential for future use (in brown). That category is labeled “high head/low power.” In trying to understand that, I gained some insight into how hydro-power is classified.

The word head refers to the height achievable for water to drop from one level to the other. A high head means greater than 500 feet, a low head less than 500 feet. The height we’re talking about here needs to be geological, thus due to the mountainous character of a region. That is why the brown areas correspond to such regions in the United States. Masses of water must be contained, and a man-made “head,” thus a reservoir resting on monstrous concrete pillars, would be too costly.

The word power refers to electrical capacity an area is capable of generating, measured in megawatts (MW). This measure is an indirect way of speaking about the amount of water available. The more water, the greater the power potential. A high power is 1 MW or greater; a low power is less than 1 MW.

MW refers to a capacity to generate power all at once, thus without reference to time. Turn it on, and its turbines put out that amount immediately. The flow of energy, the actual output, is designated by kilowatts per hour (kWh). In 2008 the U.S. generation was 4.156.7 billion kWh.

Based on the above, hydro plants are classified as High/High, High/Low, Low/High, and Low/Low. The brown area on the map (never mind DEA’s use of the word orange) represent areas where drop distances are 500 feet or greater but the water available is such that power potential is less than 1 MW. DEA’s selection of this midlevel potential is because the High/High situations have been mostly exhausted already. To look at the top category, here is a tabulation of the top five hydro-power sites in the United States sorted by capacity.

Some notes to this table:

• Coolee, Bath County, and Hoover would be classified as High Head/High Power whereas Niagara and John Day would be classified as Low Head/High Power.
• The actual height of Niagara Falls (the natural phenomenon) is 167 feet. The head in the power facility at Niagara Falls is achieved by diverting water from the river to another point.
• The Bath County, Virginia facility is pumped storage, meaning that water is held in two reservoirs, one high, one below the power station. In periods of high power demand, water is released to generate power. In periods of low demand (late at night), the water is pumped back to the high reservoir.
• The Hoover Dam is on the border between Arizona and Nevada.

What the DEA map tells me is that we do still have a lot of potential—but to exploit it we need to build many, many small plants—until the brown regions turn yellow. The Chinese have a saying: Yellow is the Middle Way—thus it is the route we must find to avoid both Scylla and Charybdis. (If that last phrase puzzles you, look here.)

Electric Leaders: Nukes and H2O

A table appearing in the 2011 United States Statistical Abstract (here) provides an interesting view of power generation across the globe in 2008. Some extracts from that table are graphed here. I am presenting one bar-graph on the top twenty countries in nuclear electric —and another on the top twenty in hydro-electric generation.

The United States produces 19.4 percent of its electric power using nuclear technology but ranks a distant thirteenth among the twenty leaders in the world. (I like that ranking. We’re contrarians in this family, and 13 is our lucky number.) Notice that Europe is very prominent on this list—and France leads the pack. At 78 percent of its total electricity, it generates 22.2 percent more than its nearest rival, Belgium, at 58.8 percent.

This bar graphs shows the top twenty in hydro-power generation—something of a misnomer. Hydro power relies on gravity. Water is its medium. And capturing tidal power is also due to the gravitational pull—of the moon. Here I show the United States as the twenty-first country. The U.S. doesn’t make the top twenty, but I thought I’d show us by way of comparison. Russia, another country with a large land area, produces 18.3 percent to our 6. China produces 14.1 percent. The leader is Paraguay. And speaking of Paraguay, notice the strong representation here by Latin American countries. Four of the top five are Latin American—and they’d sweep if Norway would not be butting in so powerfully. Aren’t they satisfied to have off-shore oil and gas. Ah, these northerners.

Five countries make both lists. These are, in order of their hydro-rankings, Sweden, Argentina, Romania, Russia, and Finland. And in their nuclear rankings, Sweden (again), Finland, Russia, Romania, and Argentina. Most balanced in this sub-list are Sweden and Russia. Both produce roughly the same percentage of electricity from both nukes and hydro-electric.

You might think that countries ranking high in hydro had it made. Nukes have the major problems of safety and waste disposal. Hydro-electric has the problem that dams eventually silt up and natural water flow is subject to climate change. Nobody is ever dealt the perfect hand that will take the pot forever and ever more.