MXEnergy, one of several electricity suppliers in the state's deregulated market, is offering homeowners and small businesses electricity rates that are locked in, similar to power purchases by large commercial and industrial customers.

To promote its business among United Illuminating's 320,000 customers, the Stamford-based MXEnergy is auctioning off 1 megawatt of electricity to the highest bidder before Dec. 13. As of Friday afternoon, the highest of 18 bid's was $132.50.

MXenergy will accept the highest bid on a megawatt, or 1,000 kilowatts, of electricity and divide it by 1,000 to determine the rate at which the winner can purchase up to 10 megawatts in a year after signing up with MXenergy.

That's about how much electricity an average household uses annually, said Jeffrey Mayer, president and chief executive of MXEnergy.