A franchise tax, measured by gross receipts, is imposed, for each calendar year, on each public service company: engaged in a telephone business in the State; or engaged in the transmission, distribution, or delivery of electricity or natural gas in the State. The tax imposed under subsection (a) of this section does not apply to a public service company that is: a county; a municipal corporation; a nonprofit electric cooperative; or a public–private partnership formed for the generation of clean or renewable energy if: 30% or more of the electricity generated through the public–private partnership is purchased by the public partner; and the clean or renewable energy generating station is sited on an eligible clean and renewable energy generation site as determined by the Department of the Environment, including: rooftops; parking lots; landfills; brownfields sites; voluntary cleanup program sites; reclaimed mines; Superfund sites; and sediment or retention ponds. The Department of the Environment may adopt regulations regarding the determination of eligible clean or renewable energy generation sites under subsection (b)(4) of this section.