This Dam Simple Trick Is A Big Green Energy Win


Other countries are already harnessing this potential. Since 2000, 36 U.S. dams have been retrofitted with turbines, adding more than 500 megawatts of renewable generation capacity. There’s even more potential out there: A 2016 U.S. Department of Energy report found that an additional 4.8 gigawatts of electricity could be generated by retrofitting of non-powered dams over the next three decades. In places like the U.S. and Western Europe, where the dam-building boom of the mid-20th century is long gone, retrofitting may be the only option left for governments looking to recover. a little hydropower. “If there are dams that remain in place, we will try and find solutions and work together on the best solution,” McManamay said.

But before anyone starts upgrading all of these dams, they can look at the numbers. It is not easy to accurately predict how much electricity will actually be produced by a retrofitted facility, as it turns out that not all dams are suitable for conversion. Let’s say someone wants to fit turbines in a dam built to hold water so it can be used to irrigate farmers ’fields. During growth, much of the water is usually directed to the plants, rather than flowing over the dam to generate electricity. Or maybe it’s in an area where the water is high enough to generate electricity for a part of the year. Suddenly those retrofitted dams may not be such a wise idea.

A recent study of retrofitted dams in the US, also commissioned by the Department of Energy, found that projections of their power output deviated to the optimistic side: On average, those projections were 3.6 times larger than the actual output. The study found that the most successful retrofits were concrete dams that were initially built to aid navigation. (Dams are often used to widen or deepen waterways to make it easier for boats to pass through.) “This is a complex issue. It’s not a quick fix, ”McManamay said.

But in countries like Brazil, large dams are still on the agenda. “If they are to develop and really raise the standard of living across the country, they need energy. That’s the long and short of it, ”said Michael Goulding, a senior aquatic scientist with the Wildlife Conservation Society. The country’s latest 10-year energy plan outlines nine new major dams scheduled to be completed before 2029. Rather than expecting these dams not to be built, it’s important to make sure the right studies are done to make sure they’re built in a way that minimizes environmental damage, Goulding says: “Often the environmental impact structures are not very good.They define an area of ​​interest near the dam and that area of ​​interest does not include all the bottom effects and also the top effects.

The Belo Monte Dam is a good example of how much impact large dams have on the surrounding environment. The dam complex redirects 80 percent of Xingu’s flow from the 62-mile section of the river known as Big Bend. This section of Xingu is also the only known wild habitat of Zebra Pleco — an attractive striped catfish loved by aquarists. “There is a high risk that this species will become extinct,” said Thiago BA Couto, a postdoctoral researcher in the Tropical Rivers Lab at Florida International University. The impact of dams on fish species is well documented elsewhere in the world. In Washington state, the Elwha Dam cut off the upper and lower Elwha watersheds, reducing habitat present in salmon by 90 percent. Some species in the river have disappeared altogether, while the populations of others — such as the Chinook — have declined a fraction of their former levels.

Eventually, however, even large dams can live up to their usefulness. In 2014, the last remnants of the Elwha Dam were removed forever. Chinook salmon that for decades remained locked behind two dams is now slow. made their way back over the river. Full recovery is expected to last decades. “Dams won’t last forever,” Couto said. “There’s a lot of abundance, but it doesn’t provide the minimum benefits they need.”


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