Mainers have spent $132.5 million more than they needed to on electricity over the past seven years. It’s not because of a faulty billing system or a mistake. It’s because of a legal market for reselling electricity to residential customers that blossomed in 2012 and since 2014 has struggled to compete with the power Mainers get by default, called the standard offer. The rate from “competitive electricity providers,” can be pennies or fractions of a penny different.