Electricity customers of Commonwealth Edison are expected to save some $12.2 million this summer, or roughly $43 each, before a slight increase in the fall and another huge drop in June 2013, the company said in a release on Tuesday.

The release came in response to confusion that arose over the year-long "roller coaster" of rates that had previously been explained. The guide, written by the Citizens Utility Board (CUB), hopes to simplify the changes in electricity rates ComEd customers will soon see.

"We've all bought a ticket to this roller coaster, so we should understand where it's going," CUB executive director David Kolata said. "The good news is electric bills will be down this summer and next–but you should be prepared for higher rates in between."

Both the supply and delivery pricing schemes will decrease for majority of this summer. The CUB says each customer could save up to $11 per month from June through September, compared with the same period in 2011.

ComEd is competing with low electricity rates offered by retail energy providers, which have appeared after the state passed energy deregulation laws in 1997.