Is "run-of-the-river" hydroelectric power greener than regular hydro?

Q. The green power program offered by my utility is 65 percent "run-of-the-river hydroelectric" power. What is this? Is it much greener than what the utilities regularly offer? Is it my greenest water-derived power option? –Audrey, White Plains, NY 

A. Imagine you’re a beaver, or a fish, or a tadpole, and you’ve made your cozy home in the same river ever since you were born. Now imagine a team of construction workers shows up and builds a huge concrete dam right in the middle of your home, leaving your once-fresh water stale and stagnant. Kind of a bummer, right? Large dams, while they do produce renewable energy, can interfere with water quality and fish migration, as well as degrade surrounding habitat.

That’s why run-of-the-river hydroelectric power, a technology that produces renewable energy without using dams to back water up, is in fact a better choice. The term “run-of-the-river” usually refers to power that’s generated from the force of water flowing from a high elevation to a lower one, using water’s natural flow. “Run-of-the-river is certainly considered better for aquatic wildlife and ecosystem management,” says Pierre Bull, policy analyst for the Natural Resources Defense Council.

Two drawbacks worth noting: One, there aren’t that many suitable places to build run-of-the-river projects (you’re in luck though—the Northeast is where most of the good spots are concentrated). And two, “run-of-the-river” is not an industry-regulated term. According to Fred Ayer, executive director of the non-profit Low Impact Hydropower Institute (LIHI), it’s not unheard of for power companies to try to greenwash their projects and call less-than-ideal hydro sites “run-of-the-river.” The LIHI does have a certification program for hydroelectric power, though—in order to be Certified Low Impact, a project must meet specific environmental criteria stipulating requirements for water quality and wildlife protection. If the hydro available to you isn’t certified, it’s worth giving the power company a call to quiz them on their environmental standards. Not only will it help you make your choice, it will help put the pressure on to provide truly green options. 

-         Sarah Schmidt

Eco-inquiries, conundrums, snafus? Write to