(Bloomberg) -- Chicago’s airports, libraries and water-purification plants will soon be running on 100% clean energy thanks to a deal announced by Mayor Lori Lightfoot to shift all city-wide operations to renewable sources by 2025, making it one of the largest US metropolitans to pledge such a move.  

The city signed an energy supply agreement with retail electricity supplier Constellation, with an initial five-year term beginning in January 2023, the mayor’s office said Monday in a statement. The agreement will also allow Chicago to partially source it large energy needs from a solar project that’s currently being developed by Swift Current Energy.

The statement didn’t disclose how much power the city is buying or how much it is paying for it. 

As global governments grapple with the impacts of climate change from burning fossil fuels, big and small cities alike have been making plans to reduce greenhouse gas emissions and commit to cleaner energy. Through the initiative, Chicago is expected to lower its carbon footprint by more than 290,000 metric tons each year, equivalent to emissions associated with 62,000 passenger vehicles, the statement said. 

Chicago’s participation in Bloomberg Philanthropies’ American Cities Climate Challenge helped provide the city with technical advisers for the project. (Bloomberg Philanthropies is the philanthropic organization of Michael Bloomberg, the founder and majority owner of Bloomberg LP, which owns Bloomberg News.)

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