How do I find out who actually supplies my power?

Read the supply portion of your ComEd bill, which names the supplier on that line. If it is a company you do not recognize, it is likely your city or village aggregation. The Illinois Commerce Commission's Plug In Illinois site lists current offers for comparison.

If my town dropped aggregation, did I do something wrong?

No. A suspension almost always means the town judged that ComEd's default rate now beats the contract it could negotiate, so it returned residents to that default. There is usually nothing you need to do, but it is worth confirming your rate afterward.

Can I opt out and shop on my own instead?

Yes. Aggregation is opt-out, so you can decline enrollment, stay on the ComEd default, or pick your own licensed supplier at any time. Switching does not change who delivers your power or restores it after an outage.

Is the renewable default worth paying for?

It depends on whether the green bundle adds to your rate and on what you want your money to do. The certificates support renewable generation markets, but they do not make the power at your outlet physically renewable. Compare the bundled rate against the price to compare before deciding.

Chicago buys power in bulk, and the deal rides the market

I.How a whole town ends up on one contract

Pull up your ComEd bill and find the supply line, the part that pays for the electricity itself rather than the poles and wires that carry it to your block. If you live in Chicago or one of the dozens of suburbs ringing it, the company named on that line may not be ComEd at all. It is often a supplier your city or village chose on everyone's behalf through a process called municipal aggregation, which Illinois law has allowed on an opt-out basis since communities began approving it by referendum around 2012.

The mechanics are less dramatic than the name. Your town runs a bid, picks a licensed alternative retail electric supplier (a company the Illinois Commerce Commission has cleared to sell power in the state), and mails you a notice saying you will be enrolled unless you decline. ComEd still owns the wires, still reads your meter, still handles the outage when a lake-effect storm takes a line down. The only thing that changes is who sets the price on that one supply line, and you can leave the arrangement whenever you want.

II.The honest math, and why it keeps flipping

Aggregation is a bet against one specific number: ComEd's default supply rate, often called the price to compare. That default is not ComEd's invention. It is procured ahead of time by the Illinois Power Agency through auctions that lock in blocks of power months out, which is why the regulated default can lag the live market in both directions. Aggregation saves a household money only in the stretches when the town's negotiated rate sits below that default.

For several years after 2012 it did, and the savings were real. Then wholesale prices across the PJM grid (the regional operator that runs the high-voltage system for Illinois and a dozen other states) climbed, capacity costs rose with them, and in many stretches the IPA-procured default came in at or below what towns could negotiate. Dozens of municipalities responded by suspending their programs and returning residents to the ComEd default, at which point the headline savings quietly went to roughly nothing. That is not a scandal. It is the deal working exactly as written: a bet that does not always pay.

III.The green label on the default

Chicago and several suburbs went a step further and bundled their aggregation supply with renewable energy certificates (a tradable proof that one megawatt-hour of renewable power was generated somewhere on the grid), marketing it as a green default. It is a genuine way to send money toward renewable generation. It is also widely misunderstood.

A certificate does not mean the electrons reaching your Rogers Park or Berwyn outlet are renewable. The grid is a shared pool, and PJM dispatches whatever is cheapest and available in the moment. What a REC does is support the market for renewable output elsewhere on that pool, which is worth something, though whether a green bundle adds to your rate depends on how the contract was priced. The honest move is the same one that applies to the whole arrangement: find your current aggregation rate, set it next to ComEd's price to compare, and decide with the two numbers in front of you.

IV.Worth watching this month

1. Watch for ComEd's next price-to-compare update, which shifts periodically as prior Illinois Power Agency purchases roll off, and which is the single number that decides whether your town's deal still wins.

2. Check whether your municipality has posted an aggregation contract renewal, re-bid, or suspension notice, since a suspension is routine housekeeping but quietly moves you back to the ComEd default.

3. Keep an eye on the Illinois Power Agency's annual procurement activity, the upstream process that sets the default you are being compared against.

4. Look at the Illinois Commerce Commission's Plug In Illinois offer listings before assuming either your town's rate or a private supplier's pitch is the best available.

5. Note any PJM capacity auction results that make the news, because higher capacity prices there tend to show up in Illinois supply costs a season or two later, not immediately.

Chicago buys power in bulk, and the deal rides the market

I.How a whole town ends up on one contract

II.The honest math, and why it keeps flipping

III.The green label on the default

IV.Worth watching this month

Questions readers have asked

Sources of record