Eight years ago, the City of Chicago vowed to eventually run all its operations on carbon-free power. Now, it has fulfilled that promise, thanks to the largest U.S. solar farm east of the Mississippi River—and a temporary reliance on renewable energy credits.
The city’s 400+ buildings consume nearly 800,000 megawatt-hours of electricity each year, and, “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 renewables, reports Grist.
The goal to power 100% of Chicago’s facilities and operations with green energy was first proposed in 2017 by then-mayor Rahm Emanuel. It received a major boost in 2022 when Emanuel’s successor, Lori Lightfoot, struck a US$422-million agreement to purchase 70% of the city’s power supply from a massive solar farm, developed by Boston-based renewables company Swift Current Energy.
Swift Current’s newly-completed 593-megawatt Double Black Diamond solar farm, spanning 15 square-kilometres, is the largest of its kind east of the Mississippi, capable of powering more than 100,000 homes.
Half of the solar farm’s output will cover 70% of the city’s power demand. The remaining 30% will come mostly from renewable energy credits (RECs)—though this arrangement will not be permanent, if all goes according to plan.
“We made an intentional choice to not meet our overall 100% commitment solely through offtake from the new Double Black Diamond facility,” Deputy Chief Sustainability Officer Jared Policicchio told The Energy Mix. “Instead, in the coming years we plan to focus on various strategies to encourage and deploy renewables, other distributed energy resources like battery storage, and energy efficiency, so that the remaining portion of our commitment—30% of our usage, a sizable 300,000 megawatt-hours—occurs locally or in the nearby metro areas.”
An initial project now ongoing involves installation of rooftop solar, together with “comprehensive” energy efficiency upgrades, at “several Chicago Public Library branch libraries located in environmental justice neighbourhoods.”
As the city phases in this approach in the coming years, it will purchase renewable energy credits on the market to fill any gaps, “with a goal of reducing these market REC purchases eventually to zero,” Policicchio added.
Chicago’s decision not to rely on a 100% off-take from Double Black Diamond demonstrates its commitment to “additionality,” bringing new, local renewable resources into the market and onto the grid, Matthew Popkin, cities and communities program manager at RMI, told Grist.
Under the agreement with Swift Current, Chicago also secured an annual $400,000 commitment to fund clean energy work force training, with a particular focus on bringing more women into the field.
Decarbonizing America’s third-largest city’s operations will reduce its carbon footprint by roughly 290,000 tonnes of carbon dioxide annually, the rough equivalent of taking 62,000 cars off the road, writes Grist. Community involvement was critical to achieving the milestone.
“The project fulfills a long-term advocacy campaign, Ready for 100, led by Sierra Club and local community organizations, to encourage the city to make the transition to renewable energy,” said Chicago officials in a release.
