Comparison shopping for electricity could soon become less confusing, thanks to an order from energy regulators Thursday requiring more clarity on electricity rates.

The Public Service Commission ruled that the old “price to compare” formula, a weighted average of summer and non-summer rates, is no longer helpful, because customers need to use more than one number for an accurate comparison to offers from other suppliers.

“Rather than providing a helpful apples-to-apples point of comparison for offers from alternative electric suppliers, we find that the [prices] published…are confusing, can be misleading, and will often be dated,” the order said.

Instead, beginning no later than Aug. 1, utilities will have to publish several pieces of information on monthly bills, including current and known future standard utility service rates, along with the dates they are effective. For example, summer rates run from June 1 through Sept. 30 each year, while non-summer rates cover October through May.

Utilities also will need to provide the date beyond when standard service prices are known.

Suppliers often offer consumers multiple-year contracts, but their price comparisons for that entire period is not accurate because utilities do not know what the standard rates will be next year or the year after. That’s because utilities purchase power in auctions twice a year, blending power offerings from the previous four auctions to protect prices from market volatility.

For example, the price for power in summer 2011 will not be known until next spring.

“We see offers for two-year and three-year contracts from suppliers, and if they’re suggesting that discounts are of a certain percentage, we want them to be sure to say that it’s only for a certain time period,” People’s Counsel Paula Carmody said.

The problems mounted this spring when suppliers were sending out offers that looked like they would provide big savings compared to rates at Baltimore Gas & Electric Co. or Potomac Electric Power Co., but the utilities’ rates only ran through May 31. Falling market rates led to lower rates for all of the utilities and many of the utilities had lower non-summer electricity prices than the suppliers.

Under the PSC’s order, the utilities also will continue to offer the price to compare with the effective dates on bills, although at the recommendation of the Office of the People’s Counsel, the term “price to compare” will no longer appear on bills.

“We find that customers will be in the best position to evaluate supplier offers if they have both the raw price figures and the weighted average at the ready,” the PSC said.

Carmody acknowledged that providing more than one number might further confuse consumers, but said that including dates with those numbers will clear up some misinformation.