Image Credit: Pamela McCreight,
Creative Commons.
Technically, hydroelectricity is just another form of solar power, in that it's the sun's radiation that evaporates low-lying water and does the work to draw it "uphill." But taking advantage of that stored kinetic energy involves a unique set of technological and environmental challenges.
To hear some environmentalists talk, we've already exploited hydro power to max, damming all the big rivers and destroying enough salmon spawning beds already. There's even evidence that some of the larger resevoirs created by dams could be triggering earthquakes, such as the one that devastated Sichuan province in China last year
Fortunately, all that is only half the story. The other half suggests hydro may yet play a major role in looming competition to replace fossil fuels.
For example, while the big rivers in the United States are already spoken for, China some of the largest untapped hydro resources on the planet. Just 36 percent are currently being used, according to one recent report. The Chinese government wants to use another 24 percent to help wean itself off coal, which now supplies almost three-quarters of its electricity. In theory, the country has 540,000 megawatts of falling water power at its disposal, although damage to wildlife and human habitat (and earthquake risks) probably mean the practical limit is a bit smaller than that.
Even in the U.S. there are plenty of rivers that aren't producing electricity but could be. Scientific American's Linda Church Ciocci recently notedthat only 3% of the country's 80,000 dams were built to supply power. Retrofitting some of the other 77,600 dams with power-generating turbines -- a move that would destroy no additional wetlands -- could go a long way toward doubling hydro's current 8% share of the nation's electricity supply.
Some the older hydro-electric plants could be upgraded to produce more power, and then there's the potential from small-scale and micro-hydro dams. These so-called run-of-river projects don't create resevoirs and represent extremely low-impact renewable energy alternatives. Elsewhere, the equivalent of underwater windmills anchored to riverbeds could generate low levels of constant, reliable power without anyone but the fish noticing.
Individually these technologies can only supply enough juice to power a factory or a small town, but cumulatively they could make a big difference. As Ciocci wrote:
Analysts say [hydro's] capacity can double in 30 years, rivaling the growth predicted for the nuclear power industry and at a fraction of the cost. The Federal Energy Regulatory Commission is reviewing more than 30,000 megawatts' worth of new projects, equal to a third of all existing hydropower capacity and big enough to power the New York metropolitan area.
There are always going to be some environmental costs, of course. Making sure endangered species of fish aren't chewed up by the turbines is essential. But there is no free lunch, but compared to the challenge of finding an affordable way to capture and store carbon dioxide from fossil-fuel smokestacks, it's child's play.
Leave a Comment