Dams Cause Emissions, Not Hydropower

Recently, the tech blog Engadget used a misleading headline to describe a half-truth about hydropower: hydropower dams create greenhouse gas emissions. While this is technically true, what they fail to mention is that all dams create emissions, whether they use hydroelectric equipment or not.

It’s important to consider the environmental impacts of new dam construction, but don’t confuse the environmental impacts of dams with those of hydropower overall. Not all hydropower requires dams, and very few dams even have hydroelectric turbines. Hydropower can make the best of a bad situation, but stringent regulations are keeping small hydropower from doing so and are inadvertently encouraging more harmful forms of hydropower.

Scientists have known for decades that reservoirs created by dams emit methane and carbon dioxide. But all dams emit greenhouse gases, not just hydroelectric ones. Existing dams were created for flood control or storing water, and have already simplified stream flow patterns, altered fish and wildlife migration patterns, and increased greenhouse gas emissions. Since these dams already exist, policymakers should consider using them to generate a reliable stream of renewable energy. If the problem is new dam construction in general, we need to avoid building dams and make the best use of those that already exist.

Hydropower no longer relies on new dam construction as it has in the past. A study by Oak Ridge National Laboratory found that the U.S. already has 54,000 existing dams that do not generate electricity, but have potential to do so. These dams are all producing greenhouse gas emissions without generating electricity. Developers can offset these emissions by installing hydroelectric turbines that generate electricity without burning fossil fuels. Removing existing dams does not reverse their impact, and emissions drop considerably as dams age. Since these dams have already been constructed, we may as well take advantage of the hydroelectric potential.

Aside from using existing dams, some types of hydropower use man-made water infrastructure like irrigation canals and municipal water pipes. By taking advantage of man-made water delivery systems, we can add even more clean and reliable hydropower to our electric grid with virtually no environmental impact. In some cases, retrofitting pipes with hydropower can actually help reduce water pressure to safe levels with the added bonus of generating affordable electricity.

The U.S. has potential to power tens of millions of homes with environmentally-friendly hydropower, but many environmentalists are fearful that hydropower often means new dam construction. This isn’t a problem with hydropower itself, but rather with the regulations that surround hydropower development. The licensing process for small and large hydropower are often the same, which encourages developers to build the largest project possible if they’re going through the hassle of a lengthy and expensive licensing process. The process was designed to make developers consider all the implications of new dam construction, but actually created obstacles that mostly serve to dissuade small developers.

The Bureau of Reclamation or Pacific Gas and Electric can afford millions of dollars and years of legal battles to build a new large dam, but the little guy can’t. Most farmers find it too hard to get approval to construct turbines in irrigation canals that would allow them to power their neighborhood. Ranchers often can’t afford the millions of dollars necessary to install a relatively inexpensive turbine in an existing dam on their property. Your local city council doesn’t have the time or manpower to obtain the right to install a turbine in the city’s water pipes. If we want to avoid generating electricity using environmentally-harmful energy sources, we need to make it easier to invest in renewable, reliable, and clean sources like small hydropower.

Devin Stein is a policy analysis at Strata, a policy research center in Logan, Utah.

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