Gov. Pat Quinn on Tuesday signed a law requiring utilities to buy a percentage of their power from solar energy sources by 2015.
The law says utilities must purchase 0.5 percent of solar power by June 2012. The mandatory percentage doubles each year, until reaching 6 percent in 2015.
"It's very, very important that all of us embrace renewable energy. We have to be a sustainable society. We have to have a green way of thinking and a green way of acting," he said Tuesday at the University of Illinois Chicago.
He said the law is expected to create more than 5,000 jobs in the Illinois solar power industry.
An Environmental Law and Policy Center representative said similar benchmarks for wind energy have been working.
The Democratic governor also signed a law requiring homeowners' associations to inform potential residents about solar panel policies.
Last month, Chicago Mayor Richard Daley unveiled the nation's largest urban solar plant in Chicago's West Pullman neighborhood. The 32,000 solar panels there will generate enough power for hundreds of homes each year.