A legal center in St. Louis has filed suit against a Missouri commission, saying it believes a new insurance rule will discourage people from trying to produce their own solar or wind power.

The Great Rivers Environmental Law Center filed suit Monday against the Missouri Public Service Commission in Cole County Circuit Court.

The PSC regulates investor-owned electric companies as part of its duties.

The lawsuit says a PSC decision that people must carry certain levels of liability insurance if they want to produce power and feed it back to an electric utility is illegal.

The lawsuit was filed on behalf of Renew Missouri, a citizens' group that worked to get a law commonly known as the "Easy Connection Act" passed last year. It allows those who generate alternative energy a way to feed it back to their power utility.

Under the law, utilities must give credit on the bills of customers who generate excess electricity using renewable sources, like solar or wind power, and supply it to their utility during a billing period. The customers do not get cash from the utility.

This fall, the PSC issued an order that customers who produce 10 kilowatts or less of energy need to carry $100,000 worth of liability insurance, and that those who produce more than 10 to 100 kilowatts of energy need to carry $1 million worth of liability insurance, the lawsuit said.

The Great Rivers center says there was no requirement in the "Easy Connection Act" that customers needed to purchase insurance.

"The PSC's rule will discourage people from producing their own electricity," lawyer Henry Robertson with the Great Rivers center said in a statement. "The Easy Connection Act is supposed to make it easy to do that. This rule negates the spirit and the letter of the law."

An attorney for PSC, Kevin Thompson, said the agency acted within its authority when it set the insurance requirement. In fact, he said the commission was doing exactly what it is supposed to do.

"When you grant rule-making authority, you're telling the agency to fill in the gaps," he said. "That's the purpose of the administrative agency."

He said utilities felt the insurance was necessary, so they wouldn't be held responsible for death or injury if someone was "messing around with a generation unit."

P.J. Wilson, founder of Columbia-based Renew Missouri, said renewable energy systems in use in households have safeguards that automatically keep them from feeding electricity into the power grid when necessary.

Wilson said he hadn't found one instance of an insurance claim for one of the small, residential systems. He called them as safe as owning a television and said renewable energy systems should be "treated like other appliances in the house."

It wasn't clear how much the liability insurance coverage would cost a homeowner, with a range of estimates given Tuesday.

Wilson said that's part of the problem, as those using renewable energy systems have a hard time figuring out where to get the insurance coverage, and receive estimates that can vary greatly.

He estimated that thus far the rule might affect about 200 Missouri households that are generating their own renewable energy.