Since President Trump announced his decision to pull out of the Paris climate accord, hundreds of U.S. mayors have said they’re committed to significantly cutting their cities’ carbon emissions. More than 30 cities, including Atlanta and San Diego, have declared 100 percent renewable energy goals in the coming decades.
But is that really possible?
The story of Aspen’s path to 100 percent renewable electricity shows it’s complicated.
In 2006, the Colorado city’s utility was one of the first in the country to declare a 100 percent renewable energy goal as part of its climate action plan to reduce overall greenhouse gas emissions.
Aspen is built around the ski industry. Mayor Steve Skadron says that behind the glitz of downtown stores like Prada and Gucci is an environmental mission.
“Put aside crazy climate zealots telling everybody to sell their cars and eat tofu,” he says. “It makes economic sense for us to support these values because our economy’s based on the natural environment.”
The town had a good start with two hydroelectric plants it built in the 1980s. To get closer to 100 percent renewable energy, the city wanted to revive another hydroplant.
As part of that proposal, it spent millions on things like a custom turbine and generator, a move that Aspen voters approved. But some residents and groups ultimately worried the plan would reduce stream flows, and that would harm the environment. In 2012, Aspen voters reversed course and rejected the plan.
Instead, Aspen signed contracts to bring in hydropower, wind and biogas from other regions and states.
In 2015, the city utility became the third in the nation to be powered completely by renewable energy, Skadron says.
“It was really exciting,” he says. “It was really hard.”
All that renewable power keeps the lights on downtown. But Aspen still uses natural gas to heat homes. And when you go to ski resorts or outlying homes, the power comes from a different utility that uses some fossil fuels.
The Sierra Club is working with cities around the country to use 100 percent renewables, but Jodie Van Horn, who directs the campaign, notes “there are different factors that either enable or inhibit a city’s ease of achieving their goals.”
Today, only a few cities besides Aspen have achieved 100 percent renewable electricity or energy: Georgetown, Texas; Burlington, Vt.; Greensburg, Kan.; and Rockport, Mo. Kodiak Island, Alaska, is 99 percent renewable energy but uses small amounts of diesel as a backup fuel source.