Saturday, December 24, 2016

How to Make Hydropower More Environmentally Friendly

Hydropower provides 85 percent of the world’s renewable electricity, but comes with a hefty environmental price tag.  Here’s what some are doing to fix that.

One way to make dams more sustainable is to not build new ones, but instead modify non-powered dams, like the Opekiska Lock and Dam in West Virginia (pictured here), to generate electricity. The U.S. Department of Energy estimates that equipping such dams with these capabilities could provide as much as 12 gigawatts of renewable energy and cost less than creating brand new powered dams. (Photo Credit: U.S. Army Corps of Engineers) Click to Enlarge.
Humanity got its first large-scale electricity thanks to hydropower.  On Aug. 26, 1895, water flowing over Niagara Falls was diverted to spin two generators, producing electricity to manufacture aluminum and carborundum.  Since then, millions of dams have been built worldwide, transforming the energy of moving water into the energy of moving electrons.  When we need it, the water spins magnets past a coil of copper wire to give us heat, light and entertainment.

The basics of hydropower haven’t changed much in 120 years.  But now scientists and engineers are taking a fresh look at hydropower to try to make it more environmentally friendly.

That’s because, while hydro provides 85 percent of the world’s renewable electricity, it comes with a cost.  Along with more commonly known issues such as habitat disruption, recent studies suggest reservoirs created by hydroelectric dams are a significant source of greenhouse gas emissions.

The U.S. Department of Energy is among those working to make hydropower better for the environment.

“Not only DOE, but really the entire hydro industry has agreed that more work needs to be done,” says Hoyt Battey, manager of market acceleration and deployment for the agency’s Wind and Water Power Technologies Office.  “Hydro is going to continue to grow and has a lot of future opportunity that most people just aren’t aware of.”

Current global hydropower production is estimated at 1,700 gigawatts, providing about 2 percent of total electric generating capacity.

In the U.S. — where in 2014 hydropower provided a little more than 6 percent of total electricity generation and made up about 48 percent of renewable generation, according to the DOE — hydropower capacity grew by 1.5 GW in the decade prior to 2015, reaching a total of 100 GW, according to the Energy Information Administration.  (Wind, solar and natural gas capacity grew faster, while coal and oil declined and nuclear was essentially flat.)

In a Hydropower Vision report released in July 2016, the DOE estimates U.S. hydropower could grow a surprising 50 percent by 2050.
Since more hydropower seems inevitable, many are looking for ways to reduce its adverse impacts.

The DOE is working to develop modular “plug-and-play” hydropower units that could be installed in many different settings.  Maintaining healthy natural stream functions is a primary objective of this effort to ensure that the expansion of hydropower does not expand its harmful impacts, also.

At the same time, the department is developing new environmental metrics to assess the environmental performance of new hydropower.  The peer-reviewed process starts with defining what sustainability means for hydropower, then setting performance measures for different environmental effects, such as fish migration, energy efficiency and greenhouse gas emissions.

Battey says a major share of the growth will come by adding generation to existing unpowered dams and other structures, like irrigation canals, navigational locks and even pipelines.  There are about 2,200 dams in the U.S. producing hydropower, and about 85,000 that don’t.  Of these, the DOE estimates about 1,800 could be modified to generate electricity.

Read more at How to Make Hydropower More Environmentally Friendly

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