SPRINGFIELD - A nonprofit group hopes their method of buying electricity could mean cheaper power bills for many Illinois residents, especially Ameren customers.

But first, they need people to join their cooperative. And there's no guarantee their method will work.

New Illinois Cooperative Energy made a pitch for members Wednesday during a news conference at the Illinois Capitol, saying customers who have their electricity delivered by Ameren can buy the energy itself from them, probably at a discount.

To do it, they'd pool the buying power of thousands of members, then buy electricity on the fluctuating market when it becomes the cheapest.

The group's parent company, Greenville-based Southwestern Electric Cooperative, has been using the method for more than 20,000 customers in Illinois for decades.

Alan Libbra, president of the Southwestern Electric Cooperative, said his customers haven't received a rate increase in 18 years. But with volatile markets, it's not an absolute guarantee that cooperative customers would get better rates than they typically do through Ameren.

"We can't make that claim," Libbra said.

If people decided to sign up for New Illinois Cooperative Energy, their electricity would still be delivered by Ameren. So delivery charges that make up 30 percent of most power bills wouldn't be affected. Many Ameren customers recently saw those charges raised.

Ameren spokesman Leigh Morris said the company encourages customers to shop around for the best deal because the utility doesn't make money on the sale of the electricity itself.

"Choice for residential customers is important," he said.

The new cooperative needs 7,000 members to get started at a $4 per month membership fee each. They'd start in 2009, and members would be bound by a five-year contract they can get out of by paying a fee.

mike.riopell@lee.net|789-0865