Mass. Gen. Laws ch. 164, § 55

A town which has established or votes to establish a gas or electric plant may elect a municipal light board consisting of either three or five citizens of the town, each for a term of three years. Of the three-member board, initially one shall be chosen for one year, one for two years, and one for three years, and at each annual meeting thereafter one for a term of three years. Of the five-member board, initially one shall be chosen for one year, two for two years and two for three years and thereafter, the terms shall be for three years. The municipal light board shall have authority to construct, purchase or lease a gas or electric plant in accordance with the vote of the town and to maintain and operate the same.