18 CFR § 292.305 - Rates for sales.
(a) General rules.
(1) Rates for sales:
(i) Shall be just and reasonable and in the public interest; and
(ii) Shall not discriminate against any qualifying facility in comparison to rates for sales to other customers served by the electric utility.
(2) Rates for sales which are based on accurate data and consistent systemwide costing principles shall not be considered to discriminate against any qualifying facility to the extent that such rates apply to the utility's other customers with similar load or other cost-related characteristics.
(b) Additional services to be provided to qualifying facilities.
(1) Upon request of a qualifying facility, each electric utility shall provide:
(i) Supplementary power;
(ii) Back-up power;
(iii) Maintenance power; and
(iv) Interruptible power.
(2) The State regulatory authority (with respect to any electric utility over which it has ratemaking authority) and the Commission (with respect to any nonregulated electric utility) may waive any requirement of paragraph (b)(1) of this section if, after notice in the area served by the electric utility and after opportunity for public comment, the electric utility demonstrates and the State regulatory authority or the Commission, as the case may be, finds that compliance with such requirement will:
(i) Impair the electric utility's ability to render adequate service to its customers; or
(ii) Place an undue burden on the electric utility.
(c) Rates for sales of back-up and maintenance power. The rate for sales of back-up power or maintenance power:
(1) Shall not be based upon an assumption (unless supported by factual data) that forced outages or other reductions in electric output by all qualifying facilities on an electric utility's system will occur simultaneously, or during the system peak, or both; and
(2) Shall take into account the extent to which scheduled outages of the qualifying facilities can be usefully coordinated with scheduled outages of the utility's facilities.