Michigan’s legislature passed a clean energy package that mandates 100% carbon-free electricity by 2040, vaulting the US industrial heartland state into an unlikely leader on climate change.

Senate Bill (SB) 271, along with other legislation that boosts energy efficiency requirements, facilitates clean energy siting and permitting, and aid to fossil-fuel communities and workers impacted by the electric power transition, passed by narrow majorities of Democrats in both houses.

"With passage of these game-changing bills, Michigan will become a national leader on clean energy," said governor Gretchen Whitmer, a Democrat.

Republicans and business groups, who successfully opposed earlier efforts to end or greatly diminish the state’s heavy reliance on coal and natural gas, also united in a losing lobbying effort against SB 271.

They argued the new mandate will increase cost of energy for manufacturers in the state, making them less competitive, and endanger electricity supply given intermittent nature of renewables and limitations of battery storage.

In August, the last month for which data is available, Michigan industry paid an average 8.25 cents/kWh for electricity. This was below the national average of 8.82 cents/kWh, according to Energy Information Administration, the statistics arm of the Department of Energy.

SB 271’s mandate requires that 50% of utility electricity sales come from renewable energy by 2030 and 60% by 2035, versus 12% last year. This is an aggressive timetable with natural gas providing 34% of the state’s power mix and coal 29%. Nuclear, at 22%, is the other large electricity source.

To get to the 100% clean mandate, the law allows nuclear power along with natural gas-fueled electricity from generators able to capture at least nine-tenths of their carbon emissions.

Environmental groups were critical of inclusion of carbon capture, contending the technology is not cost-effective or proven.

Connecticut, Minnesota, New York, and Oregon have a similar carbon-free timeline, but those states are not on the same level as Michigan for heavy industry and manufacturing.

Michigan features large cement, chemical, and steel production and is home of the US automotive industry, which has numerous plants there.

Michigan ranks 10th among states for carbon emissions after Texas, California, Florida, Pennsylvania, Ohio, Louisiana, Illinois, Indiana, and New York.

American Clean Power Association (ACP), a national trade group based in Washington, DC, praised the laws, calling them a “major step forward for Michigan.”

Clean Grid Alliance, a regional renewable energy advocacy group in the Midwest, said reforms in the package “ensure a predictable and stable permitting environment that will unlock billions in economic development across the state for decades to come.”

This refers to new authority granted to the Michigan Public Service Commission to approve large solar, wind, and battery storage projects and make it easier to deploy clean energy in the state.