Municipal and cooperative electric utilities are owned by the shareholder customers they serve and are overseen by a publicly-elected board of officers who represent the people. All such utilities are not-for-profit. Excess earnings (profits) accrued by the end of each year are given back to the local government they serve in lieu of taxes and also very often are returned to customers in a form of a monthly billing discount as well.
Typically the town of Hingham Light Plant's customers enjoy a 10 percent discount year-round. That has been the case since 1894 when the department was formed. Exemplary operations and cost saving measures during some years have periodically allowed 20 to 25% bill discounts towards year end to disburse the remainder of excess earnings. This practice is commonplace among the 2,000+ publicly owned power systems in the United States. Ordinarily such excesses or profits are distributed to stockholders if the utility is privately owned.