Notwithstanding the provisions of subsection (a) of section 16-245, the provisions of said section shall not apply to (1) any municipality or regional water authority that aggregates the sale of electric generation services, or to the Materials Innovation and Recycling Authority if such authority aggregates the sale of electric generation services, for end use customers located within the boundaries of such municipality or regional water authority, (2) any municipality that joins together with other municipalities to aggregate the sale of electric generation services for end use customers located within the boundaries of such municipalities, or (3) any municipality or regional water authority that aggregates the purchase of electric generation services for municipal facilities, street lighting, boards of education and other publicly-owned facilities within (A) the municipality for which the municipality is financially responsible, or (B) the municipalities that are within the authorized service area of the regional water authority. Any municipality or regional water authority that aggregates in accordance with this section shall register not less than annually with the Public Utilities Regulatory Authority on a form prescribed by the authority.