By John Rogers

Clean energy has been having a really good run in recent years: costs falling, scale skyrocketing, millions of people enjoying its benefits. And the future is looking bright in a lot of ways, with technologies, customers and policies coming together in beautiful harmony for a whole lot more progress to come.

When it comes to the role of our 50 states in creating this great clean energy momentum, which ones do we have to thank? That's what the new Clean Energy Momentum State Ranking from the Union of Concerned Scientists set out to discover. As for how to figure out who's tops, that title says it all … if you just look at each piece.

Let's break it down, build it up and see what we get. (And some of the answers just might surprise you.)

Gauging Leadership on Clean Energy Momentum

The map gives a sneak peek at the results from the new analysis.

And here's how the pieces of the title come into play:

Clean energy. Our focus was the electricity sector, but that turns out to include a range of pieces, and it's important to think about the multiple dimensions of "clean energy":

Renewable energy—wind, solar, geothermal, hydroelectric and bioenergy—is an obvious component, but certainly not the only one.

Energy efficiency figures in strongly in terms of how we make progress: Doing more with every electron means needing less electricity from some of our dirtiest sources, and having our renewable electricity take us further.

Transportation electrification is an increasingly important piece of the power sector picture, and cleaning things up. For most U.S. drivers, electric vehicles (EVs) give strong environmental benefits. And those benefits are going to keep going up as the country's electricity mix gets cleaner.

Our new analysis includes all three sectors.

Momentum. This is one of the things that's unique about this analysis. We were interested in capturing not just where states are now, but also where they've come from recently, and where they're headed.

Clean energy momentum covers "now" things like the renewable electricity fraction of a state's generation, its electricity savings, its EV sales, and its clean energy jobs.

But it also includes the "where ya coming from?" piece, like how much a state's renewables fraction has increased recently, and how much its power plant pollution has decreased.

And momentum in the clean energy space is about the "still to come" part—how much renewable energy is happening in the near future, and what kind of policies (for renewables, efficiency and carbon pollution, for example) will give clean energy oomph in the years to come.

Our analysis measures all that.

State. Why focus on the states when we need the federal government to be doing its thing? It's clear that we need both.

States have been a powerful, positive force for progress on clean energy, through different political climates and different federal administrations. Given the uncertainty of leadership from Washington, DC (to put it mildly), we definitely need states to continue to lead in each of these areas, to keep the momentum going—and growing.

That's why focusing our analysis on state performance made sense … not as the whole picture, but as a key part of the picture.

Ranking. We wanted to keep this simple and easy-to-understand, while covering the bases that needed covering. So our ranking incorporates a dozen metrics covering that range of sectors and time periods.

And we wanted to keep it grounded. The assessment gauges how states are doing relative to a really important yardstick: their peers. For each of the metrics, states could earn up to 10 points. We let the best-performing state define that top end, and set the zero-point level based on the worst-performing state. States got their points for that metric based on where they were on that worst-to-best scale.

The Envelope, Please

So, all together, those pieces gave us Clean Energy Momentum: Ranking State Progress. And when we put it together and looked at the numbers, here's what we found.

The top performers overall include a mix of West Coast, Northeast and Midwest states:

One surprise is who ended up on top. Yeah, I get that California might not seem like a shocker. But we were really careful, in designing the analysis, to make sure the metrics didn't give extra credit to big states, so that we'd have a level playing field for measuring leadership. All the figures were "normalized" in some way, with calculations per capita, per household, as a percent of generation or car sales or whatever. And yet California still tops the rankings.

Interestingly, the Golden State gets there not by being at the head on a bunch of metrics—it is #1 only on one (EV sales as a percent of overall car sales last year)—but by being a stellar, all-around performer. It shows up in the top five list for a total of seven metrics, and in the top 10 for still another.

In spot #2 is Vermont, which leads on two of the metrics: clean energy jobs per capita and carbon reduction target. But it also has a total of five top five appearances, in electricity savings, energy efficiency policy and EV adoption. Its record of 10 top 10 appearances is the most of any state.

Massachusetts captures #3 with the strongest energy efficiency resource standard (a leading policy for driving efficiency), and top five performances also in residential solar capacity per household, electricity savings, clean energy jobs per capita and carbon reduction targets. And it earned nine top 10s.

Rhode Island, #4, is in there because of its top electricity savings numbers, and its top-fiveness in pollution reduction and policies around renewables, efficiency and carbon reduction.

And Hawaii rounds out the top five. The Aloha State tops our residential solar metric (by a long shot) and is a strong performer for EV adoption and renewables policy.

Oregon, Maine, Washington, New York and Iowa round out the top 10 states. And those states are followed by Maryland, Minnesota, Colorado, Arizona and Nevada.

Metric Surprises

But the results are a lot more than the top overall states. The nice thing about the multiple metrics is getting to see not just who leads overall, but who leads on different pieces. And looking at it that way produces some surprising findings. For example:

South Dakota may not be the first name that comes to mind when you're thinking about renewables, but it turns out to have the highest renewable energy portion of its in-state generation—hydro, yes, but also wind. It also ties with New Hampshire for the top spot in our power plant pollution reduction metric. That makes SD one of only two states (with Vermont) to get two #1s.

Wyoming might bring to mind coal, not clean energy, but it tops our metric on new renewable energy capacity—how much is being built around now and in the near future, per capita and as a percentage of new power plant capacity.

Those who know wind might not be surprised to see Kansas somewhere on the leader board, and indeed it is: #1 for the increase in its renewable energy generation percentage, based on a tripling of its wind (from eight percent of its in-state generation to 24 percent).

For clean energy jobs per capita, the basis for another metric, Vermont tops the efficiency piece (along with overall clean energy jobs per capita) and Nevada leads on solar, but tops on wind jobs is North Dakota.

While our main focus is on the states that perform well across metrics, it's helpful to see who's moving forward in different ways.

Pedal to the Metal

Overall, the range of metrics incorporated in the UCS Clean Energy Momentum State Ranking paints a picture of state successes and a 50-state race for clean energy leadership. And the analysis points to recommendations for states as they build on clean energy momentum and continue strong progress toward a new energy future, like these:

States have to continue to drive clean energy momentum by adopting policies for continued progress in a whole lot of areas, from renewable energy and efficiency, to vehicle electrification, to economy-wide reductions in global warming pollution.

States should focus more on making sure that everyone shares in the benefits of clean energy, particularly low-income households and communities of color, those who are most affected by power plant pollution and other imbalances in the electricity sector.

States have got to push the federal government to accept its own responsibility for leadership in the clean energy space, given the value of strong national policies in a lot of these areas.

But, however we do it, we need, as a society and a country, to be picking up the pace. For clean energy jobs. For clean air and better public health. For a more just energy system.

And with an administration in the White House that seems more enamored of the brake pedal than the accelerator, where states are willing and able to lead on clean energy, we need them to be even more solidly in the driver's seat.

To clean energy momentum, then—and step on it!

John Rogers is a Union of Concerned Scientists senior energy analyst with expertise in renewable energy and energy efficiency technologies and policies.