Any town or city may establish a hydroelectric fund to hold a portion of the revenue received from its hydroelectric plant. The hydroelectric fund may be established by a majority vote at an annual or special town meeting or majority vote of the city council. If established, the town or city treasurer shall have custody of the hydroelectric fund, and shall pay out the same upon orders of the selectmen or city council, after the specified sum to be withdrawn has been authorized by a majority vote at an annual or special town meeting or majority vote of the city council. Money from this fund may be used for any purpose for which the town or city may appropriate money.