On June 9, 2025, the City of Chicago announced a significant milestone in its commitment to sustainable energy: 70% of its municipal operations are now powered by renewable sources. This achievement is largely attributed to the commissioning of the Double Black Diamond Solar Farm, an 800-megawatt facility located approximately 30 miles west of Springfield, Illinois. As the largest solar farm east of the Mississippi River, it plays a pivotal role in supplying clean energy to critical city infrastructure, including O’Hare and Midway airports, public schools, and government buildings.

A Decade-Long Commitment to Sustainability

Chicago’s journey toward renewable energy began in 2017 under then-Mayor Rahm Emanuel, who set the goal of transitioning all city-owned buildings to 100% renewable energy by 2025. This vision was further advanced in 2022 when Mayor Lori Lightfoot secured a $422 million agreement with electricity supplier Constellation to purchase renewable energy from developer Swift Current Energy, starting in 2025. The Double Black Diamond Solar Farm, spanning 3,800 acres, became operational in 2024, marking a significant step toward realizing the city’s sustainability objectives.

Economic and Environmental Impact

The transition to renewable energy is expected to reduce Chicago’s carbon emissions by approximately 290,000 metric tons annually—the equivalent of removing 62,000 cars from the road. Beyond environmental benefits, the project has also generated economic opportunities. Construction of the solar farm created approximately 500 jobs, and Swift Current Energy has pledged $10 million toward community benefit programs, supporting local infrastructure and education.

Looking Ahead

While 70% of the city’s municipal energy needs are now met through the solar farm, the remaining 30% is currently offset through the purchase of renewable energy credits (RECs). City officials plan to phase out RECs by investing in additional renewable energy projects, including rooftop solar installations on city-owned properties. The ultimate goal is to achieve 100% renewable energy for all municipal operations by 2030, aligning with broader state and national climate goals.

A Model for Other Cities

Chicago’s achievement serves as a model for other cities aiming to transition to renewable energy. By leveraging its purchasing power and committing to long-term sustainability goals, the city demonstrates how urban centers can play a crucial role in addressing climate change. As Mayor Brandon Johnson stated, “This transition not only reduces our carbon footprint but also sets a precedent for other cities aiming for sustainability.”