Illinois law allows municipalities and counties to purchase electricity on behalf of residential and small-business utility customers (businesses using no more than 15,000 kilowatt-hours of electricity a year) living within their borders. While municipalities choosing aggregation would be responsible for negotiating the price of power from a supplier other than the traditional utility, your utility would still be responsible for delivering that power to your home, and billing you for it. In theory, municipal aggregation allows communities to use the collective bargaining power of residents to negotiate for lower power prices from suppliers. See the list of communities that have moved forward with municipal aggregation or have a referendum on the November ballot.

Individual ComEd and Ameren customers can also choose an alternative electricity supplier on their own.

The Illinois Power Agency (IPA) is a state office that negotiates power prices on behalf of residential customers taking electricity supply from their utility. The agency buys power for the state's two largest utilities, ComEd and Ameren, which then pass the cost of power onto their customers with no markup.

Although the IPA negotiates power prices for a large number of consumers, a portion of that electricity is tied up in existing long-term electricity contracts signed following the utilities' now-abolished 2007 "reverse-auction" power-buying process. As those pricier contracts expire by June 1, 2013, the IPA will be responsible for purchasing more of the utilities’ power, and electricity prices are expected to decrease. That means there could be less opportunity to save money with alternative power suppliers in the future.

Yes, unless you opt out of the program. If a community passes a referendum approving electricity aggregation, local officials will then put out a request for proposals (RFP) and select a winning bid. Then, officials may hold a community hearing to get feedback and input from residents. Residents who don't wish to participate would have two opportunities to "opt out" of the program: So, even if your community passes a referendum, you don't have to participate in municipal aggregation if you don't want to.

If a community fails to pass a referendum but still chooses to move forward, the program would be "opt in," where residents are not enrolled until they sign up. In any case, consumers always have the option of paying their utility’s default prices—those negotiated by the IPA. Even if you choose to participate in community aggregation, your utility—ComEd or Ameren—is still responsible for delivering the electricity you purchase to your doorstep. So if the power goes out in your home, you should call your utility. In most municipalities, consumers will continue to get a single bill from their utility, but it's not a certainty. Whether or not residents will get lower electricity rates would depend on the contract their community negotiates. If not, residents can opt out of the program. While municipal aggregation has been delivering savings to communities in the short term, long-term savings are not guaranteed. The last of expensive long-term utility electricity contracts are set to expire by June 1, 2013, and the utilities’ power prices could then drop. Several expensive long-term electricity contracts for ComEd and Ameren are set to expire in May of 2013 and December of 2012, respectively, and the utilities' electricity prices could then drop.

The best way for a community to ensure long-term residential savings is not to solely rely on the market, but to include robust, creative efficiency measures in its energy plan. That will help reduce power usage at peak times, which cuts individual power bills as well as market prices. So far, CUB has not seen communities use aggregation as an opportunity to employ such efficiency measures. See a list of prices these communities have negotiated so far. So far, most communities have separated out individuals who are already under contract with an alternative supplier. It's wise to check with local officials to learn what the process will be. The rate you're offered through municipal aggregation may be better than what your current supplier is offering you. If you switch, however, you may have to pay an exit fee. ComEd's Real-Time Pricing and Ameren's Power Smart Pricing programs allow customers to pay hourly market electricity prices, rather than the utilities' fixed rates. Consumers who aren't home during the day, when energy prices tend to be highest, or who can shift high-energy usage activities like laundry or running the dishwasher to off-peak hours, benefit the most. In fact, participants have saved an average of about 15 percent on their power bills. To date, no municipal power agreements or individual alternative supplier plans offer real-time pricing options, so if you would like to enroll or stay enrolled in real-time pricing, you'll have to stick with your utility. Just like customers who are already enrolled with alternative suppliers, Real-Time Pricing and Power Smart Pricing customers will likely be filtered out when residents are switched over to the community's negotiated power supplier. Still, it's an important detail to check. Customers who use electricity to heat their homes currently pay a lower rate than non-space heat customers—but communities often have been able to negotiate even lower rates through municipal aggregation. Just like customers who are already enrolled with an alternative supplier, space-heat customers could be separated out when residents are transferred over to their community's negotiated supplier. Ask what the process is, and make sure to compare the rates you pay with the rates offered through aggregation. No matter what company supplies you with electricity, CUBenergysaver.com can help you make deep cuts in your utility bills. It recommends hundreds of simple, money-saving actions. Users can connect to their ComEd accounts to track real savings and earn rewards for their energy savings redeemable at local and national businesses. Signing up is free, and takes just a few minutes. On average, CUB Energy Saver users have cut their gas and electric bills by about $100 a year.