(a) Except as provided in paragraph (b), this part shall apply to each electric utility, in any calendar year, if the total sales of electric energy by such utility for purposes other than resale exceed 500 million kilowatt-hours during any calendar year beginning after December 31, 1975, and before the immediately preceding calendar year.

(b) The Commission exempts from compliance with this part any utility:

(1) Listed by name in Appendix A to this part; or

(2) That has total sales of electric energy for purposes other than resale of less than 2 billion kilowatt-hours per year.