Updated 03/22/12 – 9:33 a.m.

CHICAGO (CBS) — Voters in more than 50 Cook County suburbs Tuesday gave the green light to municipal officials to negotiate with other suppliers to obtain cheaper power rates than ComEd charges its residential customers.

But at least eight towns rejected identical referenda.

The referenda requested approval of municipal utility aggregation. Under such a program, entire cities and towns – and in some cases, several municipalities banding together – gain the power to bargain toward lowering what residents and small businesses pay for electricity on contracts locked in long ago.

LISTEN: WBBM Newsradio’s Bernie Tafoya reports

In west suburban Oak Park the way homes and small businesses get their electricity has changed in a big way over the past two months.

ComEd does not supply the power; a green company, Integrys, does.

Village President David Pope told CBS 2’s Jim Williams there have been no major complaints or power outages so far.

“No issues like that,” he said.

Some in Oak Park will end up saving $100 a year on their electric bills, because voters last year decided Oak Park should put up bids to find electric companies that were environmentally-friendly, and had lower costs.

They won’t be alone, people more than 50 Chicago suburbs and 300 communities throughout Illinois voted Tuesday to find different power companies. It’s called municipal aggregation.

Think of those communities like Costco super stores.

Jim Chilsen, spokesman for the Citizens Utility Board watchdog group said, “Just as Costco can secure lower prices for its consumers by buying in bulk, the theory behind municipal aggregation is that local leaders could secure buying discounts on electricity, based on the buying power of its residents.”

No community can get rid of ComEd altogether, because – as Chilsen explained – ComEd still distributes the power in communities that opt for municipal aggregation.

“You have to think of your electricity bill in two parts. There is the supply portion, which is about two-thirds of your bill. Then there is delivery portion, which is about a third of your bill,” he said.

So, Com-Ed will still deliver the power, because it owns the infrastructure.

Tuesday’s was just the start of the process for communities that voted for municipal aggregation. Those communities that decided to select other power companies will put out bids, and a handful of companies will compete for the business.

The towns will then seek the public’s input on what company is ultimately chosen.

Communities in which the referenda were rejected included Bartlett, Chicago Heights, Dolton, Elmwood Park, Lynwood, Matteson, Maywood and Midlothian.

This was the second year, under a 2009 law, that communities could seek voter approval. Identical referenda were on ballots in more than 300 communities statewide.

Communities that approved the referenda included Arlington Heights, Barrington, Bedford Park, Bridgeview, Brookfield, Buffalo Gvove, Chicago Ridge, Countryside, Evanston, Evergreen Park, Flossmoor, Forest Park, Franklin Park, Glencoe, Hanover Park, Harwood Heights, Hickory Hills, Morton grove, Mt. Prospect, Norridge, Northbrook, Oak Forest, Olympia Fields, Orland Hills, Orland Park, Palatine, Palos Heights, Palos Hills, Palos Park, Park Forest, Park Ridge, River Forest, River Grove, Riverside, Rolling Meadows, Schiller Park, Skokie, South Barrington, South Chicago Heights, South Holland, Thorton, Tinley Park, Westchester, Wheeling and Wilmette.

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