Electricity shopping tool quietly unveiled in Mass.

Shopping for competitive electricity suppliers could get a lot easier for Massachusetts households soon.

Dozens of companies that try to offer better rates than electric utilities have agreed to post their plans on a state website for households looking for a better deal. Although the current website only allows users to download price spreadsheets that are updated twice weekly, the Department of Public Utilities plans to have a full-blow marketplace up before next winter.

"We think this is going to be a very valuable tool," said Angela O'Connor, the chairman of the department.

Manufacturers and other big businesses that use lots of electricity have long shopped around for cheaper power. But for more than a decade after the state deregulated electricity markets, the overwhelming majority of households stuck with the "basic service" delivered through their utilities.

When basic service rates surged last winter, more customers started switching, persuaded by sales pitches and information they came across online. About 640,000 Massachusetts households bought their electricity from a competitive supplier in June, about 49 percent higher than a year before. 1.7 million Massachusetts households use basic service, according to state data.

With the new electricity shopping tool, customers can download a spreadsheet of competitive supply plans available in their area. They can't actually buy the plan through the state's website, but the spreadsheet contains contact information for the sellers and prices that sellers promise to fulfill. Customers can also submit feedback using a link on the DPU's web page.

O'Connor said the price website would be a natural follow-on to the DPU's April decision to abolish the practice of recalculating previous household bills when they switched to a competitive supplier. That practice resulted in surprise charges, mostly less than $100, that angered many consumers and led some to cancel their competitive-supply deal.

"This is consistent...with providing transparency for customers," O'Connor said. "This is the next step."

By next year, the state hopes to have a more polished and user-friendly website, akin to those in states such as Pennsylvania, Texas, Illinois, and Connecticut. In Pennsylvania, the percentage of households using a competitive supplier more than doubled after the state's public utilities commission rolled out its website, a spokeswoman said.