Swift Current Energy has flipped the switch on its 800 MWdc (593 MWac) Double Black Diamond Solar project near Springfield, Illinois, now the largest operating solar farm east of the Mississippi River. The ribbon-cutting, attended by Chicago Mayor Brandon Johnson and state and local leaders, marks the facility’s transition from development to powering over 100,000 homes annually. Major offtakers include the City of Chicago (100% renewable power), Cook County, CVS Health, Loyola University Chicago, PPG, State Farm, and TransUnion via Constellation NewEnergy. Moreover, the plant was built with 1.6 million U.S.-made panels, U.S. steel racking, and domestic labor, the project generated 500 construction jobs and surpassed one million safe work hours. Google led tax-equity financing; MUFG, Société Générale, Truist, and eight others funded construction.
Also Read Elisabeth Solar Project in Yuma County, Arizona receives approval
Double Black Diamond Solar spans Morgan and Sangamon counties, covering roughly 800 MWdc of solar capacity and delivering 593 MWac to the grid. What’s more, commercial operation began in 2024, with the official inauguration held in spring 2025 at the site 30 miles west of Springfield. As the largest solar facility east of the Mississippi, it represents a key milestone for renewable growth in the U.S. heartland.
Community & Economic Impact
Construction of Double Black Diamond Solar created approximately 500 jobs, focusing on local and diverse hires in line with Illinois’s Clean and Equitable Jobs Act (CEJA). Moreover, the project achieved over one million safe man-hours on site and injected capital into Morgan and Sangamon counties through property taxes and community benefit funds. Additionally, Swift Current Energy has pledged $10 million in community investments, supporting the Sangamon Growth Alliance, Auburn School District, the City of Chicago, and Cook County. Sangamon County Board Chair Andy Van Meter noted the anticipated $100 million in tax revenue over the facility’s lifetime, with 60% earmarked for public schools.
Also Read 380 MW Aldoga Solar Farm in Australia Completed 7 Months Ahead of Schedule
Project Overview
Location: Springfield, Illinois
Project cost: US$779 million
Start date: 2018
Completion date: 2024
Developers: Swift Current Energy
Project capacity: 800 MW
Environmental & Technical Highlights
Further, the project uses 1.6 million solar modules, most produced by First Solar in Ohio, mounted on Nextracker racking systems made with 100% U.S. steel. Its expected annual generation displaces fossil-fuel electricity equivalent to powering over 100,000 homes, cutting greenhouse-gas emissions by roughly 200,000 metric tons annually. Furthermore, advanced grid-interconnection equipment ensures stable dispatch into the MISO market, contributing to regional reliability and peak-load management.
Double Black Diamond Solar Illinois Key Partnerships & Customers
The City of Chicago now sources 100% of its facility power, including for O’Hare and Midway airports, from the Double Black Diamond Solar output. Constellation NewEnergy aggregates offtake for Cook County, CVS Health, Loyola University Chicago, PPG, State Farm, and TransUnion under long-term power-purchase agreements. Further, Google provided critical tax-equity financing, while construction financing was led by Mitsubishi UFJ Financial Group, Société Générale, Truist, and eight other financial institutions.
Also Read China, Saudi, Oman Partner for 2 GW Sadawi Solar Project and Wind Project
What’s Next
Swift Current Energy remains the long-term owner and operator, monitoring performance to optimize yield and reliability. The firm is already exploring adjacent sites for future expansions, leveraging the skilled workforce and strong supply-chain ecosystem fostered by this project. As renewable demand grows with new manufacturing and tech loads, Double Black Diamond Solar stands as a blueprint for large-scale, American-made clean energy developments across the U.S.
