Section 76. The department shall have the general supervision of all gas and electric companies and shall make all necessary examination and inquiries and keep itself informed as to the condition of the respective properties owned by such corporations and the manner in which they are conducted with reference to the safety and convenience of the public, and as to their compliance with the provisions of law and the orders, directions and requirements of the department; provided, however, that any alternative energy producer shall not be considered to be a municipality, manufacturing company, corporation or other person engaged in the manufacture, sale, distribution or transmission of gas or electricity and shall be exempt from regulation by the department.