When is hydropower a renewable energy source?
The answer, at least from a policy perspective, depends on the state.
How hydropower is counted toward renewable electricity standards varies from state to state perhaps more than any other type of generation.
More than 30 states have passed renewable electricity standards, which require utilities to generate a percentage of their power from renewable sources.
Every state counts some hydropower, but the fine print is far from uniform.
In the Midwest, for example:
•Iowa and Minnesota allow utilities to count electricity from small hydropower facilities only. Iowa doesn't define small, while Minnesota sets the upper limit at 100 megawatts.
•Illinois, Michigan, and Missouri don't count hydroelectricity from facilities that require the construction of new dams or significant expansion of existing ones.
•Ohio will let utilities count hydroelectricity only from facilities that are not detrimental for fish, wildlife, water quality or "cultural resources."
•North Dakota counts all hydropower in its renewable electricity standard.
•In July 2011, Wisconsin added new hydropower restrictions to its renewable standard. Utilities can only start counting hydroelectricity from large facilities after 2015.
One reason renewable policies place qualifications on hydroelectric facilities is that most of them were already built when states started discussing the policies. Counting all available hydro would significantly water down the impact in some places.
"The whole point of a [renewable standard] is to increase the amount of renewable energy in a state," says Kyle Aarons, a solutions fellow with the Center for Climate and Energy Solutions. "Since hydropower has been around for over 100 years in some areas, if they counted all hydro their targets would have to be unrealistically high or they wouldn't actually be encouraging any new renewables from coming online."
Utilities didn't need new incentives to build hydropower facilities, Aarons said. They had already been investing in hydropower for reasons other than its renewable qualities.
That was the situation in Minnesota as lawmakers were working on the state's renewable policy in 2007. Canada's Manitoba Hydro is a major power supplier to the state's utilities, and it was preparing for a major expansion at the time.
"We wanted to see Minnesota develop its own resources rather than have a standard that would allow Minnesota utilities to meet it simply by buying hydropower from a major development," says State Rep. Bill Hilty, DFL-Finlayson, one of the bill's main authors.
The environmental impact of the Manitoba Hydro project was also of concern, says Hilty. It's an issue that's come up elsewhere, too, as states drafted their renewable policies, says Rupak Thapaliya, national coordinator for the Hydropower Reform Coalition.
"Hydroelectric is not always clean," says Thapaliya. "Some states tend to be very protective of the ecosystems and they are hesitant to qualify hydro because first of all it's not as clean as say, solar."
A project's size, however, is a poor measure of its environmental impact, says Thapaliya. That's why the Hydropower Reform Coalition advocates for an approach more along the lines of Ohio, which specifically addresses environmental impact, rather than Iowa or Minnesota, which simply cap the size of facilities that are counted.
Organizations such as the Low Impact Hydropower Institute and American Rivers issue certification to hydroelectric facilities that meet environmental guidelines. Pennsylvania requires hydro to have that certification in order to be counted in renewable portfolios.
The National Hydropower Association doesn't believe that's necessary.
"Any hydro project that gets built today or that gets relicensed has to meet all of the federal and state environmental laws that are on the books," says Jeff Leahey, the associations' government affairs director.
When Congress was discussing a national renewable standard, the hydropower association supported a measure that wouldn't have counted hydro as renewable but also wouldn't have counted it in utilities' non-renewable portfolios either.
A utility that hypothetically drew 50 percent of its power from hydro and was required to generate 25 percent from renewables would base the calculation only on the other half of its portfolio that didn't come from hydro, lessening the burden.
A more aggressive clean energy policy, such as the 80 percent by 2035 target that President Obama has proposed, would need hydro to succeed, says Leahey:
"We don't think you can get to the amount of clean energy generation that policy makers are calling for unless you include hydro."
How Hydro Counts Towards States' Renewable Goals
Click on the markers to see how states count hydropower in their renewable electricity standards.
View State Renewable Portfolio Standards & Hydropower in a larger map
Source: Hydropower Reform Coalition
An earlier version of this story omitted North Dakota among states that count all forms of hydropower in their renewable standards.