BELLEVILLE — Residents have a chance Monday night to help shape the city's electric aggregation plan.

Earlier this month, Belleville voters approved a referendum to allow the city to bargain for cheaper electricity supply prices on behalf of those who do not opt out of the program. Regardless of the supplier, Ameren will continue to handle outages and billing.

Monday, residents will get more information on the bargaining process and how the opt-out process works.

Residents also can weigh in on details such as whether the city should use renewable or traditional energy sources, and the length of the city's contract with the winning supplier.

Back-to-back public hearings are at 5:30 p.m. and 6 p.m. in the Council Chambers at City Hall, 101 S. Illinois St.

After the hearings, a special City Council meeting is at 6:30 p.m. in the same location.

Mayor Mark Eckert said the city will probably aim for a two-year contract with the supplier, but aldermen will discuss these issues after hearing from residents. The contract length could be 12 months, 17 months, two years or three years.

Jerod McMorris of Good Energy, an energy management consultant company hired by the city to oversee the process, said the cost difference between traditional and 100 percent green energy is, on average, less than $1 per month per household.

Good Energy estimates average monthly savings overall to be $20 to $25. Prebidding from suppliers indicate customers will save more than 20 percent, McMorris said.

Belleville officials have yet to decide whether the city will collect an additional fee to pay for administrative costs. Belleville officials have said they lean toward not taking the fee, though about 75 percent of cities who have the program do.

On Monday's City Council agenda are two resolutions: A municipal electrical aggregation program plan of operation and governance; and, authorization for the city to contract with the lowest bidder for the supply of electricity.

The city will appoint one or two city officials to represent the city on Dec. 11. About 55 cities will decide on a supplier after several electricity suppliers present bids.

"After the bids come in, the communities will talk about lengths of terms and what makes sense for these communities," McMorris said. "They'll caucus and reach a mutual decision on the winning supplier."

Municipalities can participate in "bid day" at one of three locations -- Granite City, Decatur or Charleston -- and communicate via teleconference.

After "bid day," residents will have two chances to opt out of the program. Residents should get mailers, one from the winning supplier and another from Ameren, that will show the new rate and explain the opt-out process.

Another Good Energy representative, Philip Carr, said residents already signed on with an alternative electricity supplier, or programs such as Power Smart Pricing, should compare their savings with the new rate.

Such residents are automatically excluded from the group purchase and would need to enroll in the program.

One thing to look out for, Carr added, is whether these alternative suppliers will charge residents an early termination fee and, if so, whether it's cost-effective for the resident to end an existing contract.

"Look at what you've been paying," Carr said. "Do the math, and if it makes sense for you, call in and enroll ... Once the rates come out and they see that it's lower, it'll be a no brainer."

Contact reporter Jacqueline Lee at jlee@bnd.com or 239-2655. Follow her on Twitter at twitter.com/BNDBelleville.