When any portion of a waste to energy facility is owned, operated or leased by a governing body, the electrical supplier serving the area shall be required to enter into long-term contracts to purchase the electricity generated by the waste to energy facility at the same rate the utility charges the governing body for energy used. Provided, however, that the rate paid by the electric supplier for such energy shall be such that no other customer class or classes shall ever directly or indirectly subsidize any part of the cost of owning, operating or maintaining the trash to energy facility, unless they receive a direct or indirect benefit.