Chicago Mayor Rahm Emanuel is making a bold promise: All of the city’s public buildings will be powered by 100 percent renewable energy by 2025.

The mayor announced this goal on the roof of the Shedd Aquarium, which has embarked on its own efforts to reduce energy use. 

Transferring city buildings to renewable energy won’t be an easy feat. A press release from the mayor’s office noted that Chicago Public Schools, Chicago Park District, Chicago Housing Authority, and City Colleges of Chicago properties used nearly 1.8 billion kilowatt hours of electricity in 2016, which is equivalent to powering approximately 295,000 Chicago homes. But the mayor plans to make this happen nonetheless by “acquiring renewable energy credits, [using] utility-supplied renewable energy via Illinois’ Renewable Portfolio Standard, and on-site generation.”

The press release notes the city has already started working toward renewable energy. Chicago stopped buying coal for its energy supply in 2013, installed solar energy systems at a dozen CPS schools since 2009, and had the Park District and City Colleges shift to procuring some energy from renewable sources.

This announcement comes the same week Energy Star, a program of the Environmental Protection Agency, awarded Chicago its 2017 “Partner of the Year” award.

How would this affect the average Chicagoan? “Residents will benefit from the good jobs and cleaner air that come from renewable energy projects,” said Jack Darin, Illinois Sierra Club President, in the city press release.