In northern Illinois, you can choose Commonwealth Edison (ComEd), the regulated utility, to supply you with power, or go with alternative suppliers.

Remember, even if you choose an alternative supplier, you're simply buying electricity from that company. ComEd will still bill you to deliver the electricity to your home.

While it's an interesting development in the electric market, long-term savings are not guaranteed. The jury is still out on whether residential competition is going to bring real value to consumers in the long run.

Several companies began rolling out marketing campaigns in the wake of an Illinois Commerce Commission (ICC) decision in December 2010 that made it easier for alternative suppliers to bill for their services through ComEd. The offers below should be compared with ComEd's "price to compare," which includes the "Electricity Supply Charge" and the "Transmission Services Charge" (.765¢), both under the "Electricity Supply Services" section of ComEd bills. CUB added the transmission charge for the sake of making an apples-to-apples comparison. Make sure to confirm with the company whether any price it quotes you includes or does not include the transmission charge. The Purchased Electricity Adjustment (PEA), which can be a credit or a debit, is not included in ComEd's price to compare. In February ComEd customers are paying .5 cents per kWh for the PEA.

ComEd's price to compare is 7.733 cents per kWh through May 2012. In the short term, at least, many of these offers are beating ComEd's current price for electricity. One reason is that ComEd is locked into long-term power contracts until around 2013. Also, alternative suppliers have taken advantage of lower market prices sparked by a decrease in electricity usage in the slow economy. Another reason is the volatile nature of the electricity market. ComEd's price for electricity went up by about 19 percent in June 2010, before falling by about 5 percent this past June 1. Still, there's no guarantee of long-term savings with alternative suppliers. That's why it's important to read the fine print of these offers. If you do decide to go with an alternative supplier, make sure to follow closely the price you're paying compared with ComEd's rate into the future. Find out:

You should get a single bill, but it's a good detail to check. Also, ask if your bill will be paper or online. Most of the suppliers simply include their charges on your ComEd bill, but at least one sends you its own bill. No, remember ComEd will still charge you to deliver the electricity to your home. ComEd just received a $156 million rate hike on the delivery rates you pay, whether you buy your electricity from an alternative supplier or not. (Help us battle rate hikes!) Some companies offer green energy plans. Typically, here's how such plans work:

For a higher price than the company's standard fixed rate, the company pledges to buy "renewable energy certificates," or RECs, from a company that produces alternative energy, such as wind power. That ensures that the alternative energy company will deliver an amount of renewable energy to somewhere in the electricity system that is equal to the amount you consume.

Such programs have been a common source of customer confusion. BlueStar admits on its website, "It is not physically possible to route electrons from a specific generation source to a specific physical address." So enrolling in BlueStar's renewable program doesn't mean that the actual power you use is coming from a wind farm.

Although RECs are a legitimate option for consumers, there are other ways to help the environment without paying extra for your electricity. For example, practicing energy efficiency at home (see below) can be even more effective. Also CUB sees Illinois' renewable portfolio standard, requiring state utilities to use a certain percentage of renewable energy, as a much more effective way to make the electricity system cleaner and more stable. CUB's latest tool, CUB Energy Saver, will help you design a personalized energy-saving plan for your home. Choose from hundreds of customized actions to cut your energy bill. Plus, ComEd customers who input their billing information and save energy can earn shopping and restaurant discounts. CUB Energy Saver has been showing consumers how to cut their utility bills by an average of more than $100 a year.