The findings are part of a yearlong effort outlined by Gov. Rick Snyder's administration in January to help set future energy policies for Michigan, including whether to require expanded use of wind, sun and other renewable electricity sources.
The Republican governor vowed to explore the issue after voters soundly rejected a 2012 ballot proposal that would have ordered the state's utilities to generate 25 percent of their power from alternatives to coal, natural gas and other fossil fuels by 2025.
Existing law sets a 10 percent minimum that must be met by 2015.
The report said providers should hit that target, but that 15 percent by 2020 and 30 percent by 2035 also "are achievable." The draft report was prepared by the state Public Service Commission and the Michigan Energy Office.
"Electric providers have been working diligently to make (the 10 percent mandate) happen," the report said. "As more renewable resources have been added, the prices of these resources has decreased, particularly for wind energy, and are now competitive with some new sources of non-renewable energy."
The cost to produce energy through renewable sources is what jumped out to the Michigan Environmental Council, which campaigned for the unsuccessful ballot initiative. It said in a statement that "this report affirms what we already know — that renewable energy in Michigan is less expensive than almost every conventional alternative and costs continue to drop."
The report "unambiguously shows that investing in more renewable energy is good for Michigan ratepayers and good for our economy, public health and environment," said Chris Kolb, MEC's president.
Michigan's 10 percent mandate is less ambitious than most states that have renewable standards, the report said. In all, 29 states and Washington, D.C., have such standards.
"With the exception of Michigan and Wisconsin, all other states with renewable energy portfolio standards include targets higher than 10 percent," the report said.
The study relied in part on data and other material presented earlier this year during a series of public forums across the state.
Public comment on the draft report can be made online through Oct. 16, and the target date for release of the final renewable energy report is Nov. 4.