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It takes approximately 700,000 megawatt hours of electricity to power Chicago’s more than 400 municipal buildings every year. As of January 1, every single one of them — including 98 fire stations, two international airports, and two of the largest water treatment plants on the planet — is running on renewable energy, thanks largely to Illinois’ newest and largest solar farm.
The move is projected to cut the carbon footprint of the country’s third-largest city by approximately 290,000 metric tons of carbon dioxide each year — the equivalent of taking 62,000 cars off the road, according to the city. Local decarbonization efforts like Chicago’s are taking on increasing significance as President-elect Donald Trump promises to reduce federal support for climate action. With the outgoing Biden administration doubling down on an international pledge to get the U.S. to net zero emissions by 2050, cities, states, and private-sector players across the country will have to pick up the slack.
Chicago is one of several U.S. cities that are taking advantage of their bulk-buying power to spur new carbon-free energy development.
“It’s a plan that gets the city to take action on climate and also leverages our buying power to generate new opportunities for Chicagoans and the state,” said Angela Tovar, Chicago’s chief sustainability officer. “There’s opportunities everywhere.”
Chicago’s switch to renewable energy has been almost a decade in the making. The goal of sourcing the city’s power purely from carbon-free sources was first established by Mayor Rahm Emanuel in 2017. His successor, Mayor Lori Lightfoot, struck a 2022 deal with Constellation, an electricity supplier, to purchase the city’s energy from the developer Swift Current Energy beginning in 2025.
Swift Current began construction on the 3,800-acre, 593-megawatt solar farm in central Illinois as part of the same five-year, $422 million agreement. Straddling two counties in central Illinois, the Double Black Diamond Solar project is now the largest solar installation east of the Mississippi River. It can produce enough electricity to power more than 100,000 homes, according to Swift Current’s vice president of origination, Caroline Mann.
Chicago alone has agreed to purchase approximately half the installation’s total output, which will cover about 70 percent of its municipal buildings’ electricity needs. City officials plan to cover the remaining 30 percent through the purchase of renewable energy credits.
“That’s really a feature and not a bug of our plan,” said Deputy Chief Sustainability Officer Jared Policicchio. He added that he hopes the city’s demand for 100 percent renewable energy will encourage additional clean energy development locally, albeit on a much smaller scale, which will create new sources of power that the city can then purchase directly, in lieu of credits. “Our goal over the next several years is that we reach a point where we’re not buying renewable energy credits.”
More than 700 other U.S. cities and towns have signed similar purchasing agreements since 2015, according to a 2022 study from the World Resources Institute. Only one city, Houston, has a larger renewable energy deal than Chicago, according to Matthew Popkin, the cities and communities U.S. program manager at Rocky Mountain Institute, a nonprofit whose research focuses on decarbonization. However, he added, no other contract has added as much new renewable power to the grid as Chicago’s.
“Part of Chicago’s goal was what’s called additionality: bringing new resources into the market and onto the grid here,” said Popkin.
Chicago also secured a $400,000 annual commitment from Constellation and Swift Current for clean energy workforce training, including training via Chicago Women in Trades, a nonprofit aiming to increase the number of women in union construction and manufacturing jobs.
The economic benefits extend past the city’s limits: According to Swift Current, approximately $100 million in new tax revenue is projected to flow into Sangamon County and Morgan County, which are home to the Double Black Diamond Solar site, over the project’s operational life.
“Cities and other local governments just don’t appreciate their ability to not just support their residents but also shape markets,” said Popkin. “Chicago is demonstrating directly how cities can lead by example, implement ambitious goals amidst evolving state and federal policy changes, and leverage their purchasing power to support a more equitable renewable energy future.”
Alex Dane, the World Resource Institute’s senior manager for clean energy innovation and partnerships in the U.S. energy program, said many cities have set two renewable energy goals: one for municipal operations and a second goal for the community at large. Even though the latter is “a little bit harder to get to, and the timeline is a little bit further out,” said Dane, the community-side goals begin to seem less lofty once a city has decarbonized the assets it directly controls.
Indeed, Chicago’s new milestone is the first step in a broader goal to source the energy for all buildings in the city from renewables by 2035. That would make it the largest city in the country to do so, according to the Sierra Club.
Dane said it will be increasingly important for cities, towns, and states to drive their own efforts to reduce emissions, build greener economies, and meet local climate goals. He said moves like Chicago’s prove that they are capable, no matter what’s on the horizon at the federal level.
“That is an imperative thing to know, that state, city, county action is a durable pathway, even under the next administration, and [it] needs to happen,” said Dane. “The juice is definitely still worth the squeeze.”
This story was originally published by Grist with the headline Chicago keeps its New Year’s resolution: All city buildings now use 100 percent clean power on Jan 2, 2025.
