US PURPA 18 CFR 292 Solar Interconnection and Backup Rates Guide

Key Takeaways

• Electric utilities must interconnect with qualifying facilities for purchases or sales under 18 CFR 292.303.
• Utilities must offer parallel operation with qualifying facilities, provided standards are met, as per 18 CFR 292.303.
• Backup power rates cannot assume simultaneous forced outages of all qualifying facilities, according to 18 CFR 292.305.
• Qualifying facilities are obligated to pay nondiscriminatory interconnection costs, which may be amortized over time, under 18 CFR 292.306.

Understanding US PURPA 18 CFR 292 for Solar Interconnection

The Federal Energy Regulatory Commission (FERC) regulations under Title 18 Code of Federal Regulations (CFR) Part 292 establish requirements for electric utilities regarding solar qualifying facilities. These regulations cover interconnection obligations, mandatory parallel operation, and the provision of backup power. We checked on 23 August 2026.

Under 18 CFR 292.303, any electric utility "shall make such interconnection with any qualifying facility as may be necessary to accomplish purchases or sales under this subpart." This provision mandates that utilities facilitate the physical connection required for transactions with qualifying solar facilities.

Mandatory Parallel Operation and Utility Sales Obligations

Electric utilities are required to offer parallel operation with qualifying facilities. Specifically, "Each electric utility shall offer to operate in parallel with a qualifying facility, provided that the qualifying facility complies with any applicable standards established in accordance with paragraph (f) of this section." This ensures that solar facilities can operate synchronously with the utility grid.

Furthermore, 18 CFR 292.303 states that "Each electric utility shall sell to any qualifying facility, in accordance with § 292.305, unless exempted by § 292.309 and § 292.310." This establishes the utility's obligation to provide power to qualifying facilities when requested.

A jurisdictional exemption exists: "No electric utility is required to interconnect with any qualifying facility if, solely by reason of purchases or sales over the interconnection, the electric utility would become subject to regulation as a public utility under part II of the Federal Power Act."

Backup Power and Maintenance Power Rates

When a qualifying facility requests supplementary, backup, or maintenance power, the utility must provide it. The rates for these services are subject to specific standards under 18 CFR 292.305. These rates "Shall be just and reasonable and in the public interest." They "Shall not discriminate against any qualifying facility in comparison to rates for sales to other customers served by the electric utility."

The regulations also specify how these rates must be designed. Rates "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." This prevents utilities from overestimating the cost of providing backup power. Additionally, rates "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."

Consistent costing principles are also addressed: "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."

Interconnection Cost Assessment and Reimbursement

Qualifying facilities are responsible for interconnection costs. "Each qualifying facility shall be obligated to pay any interconnection costs which the State regulatory authority (with respect to any electric utility over which it has ratemaking authority) or nonregulated electric utility may assess against the qualifying facility on a nondiscriminatory basis with respect to other customers with similar load characteristics."

State regulatory authorities or nonregulated utilities determine the payment method for these costs. "Each State regulatory authority (with respect to any electric utility over which it has ratemaking authority) and nonregulated utility shall determine the manner for payments of interconnection costs, which may include reimbursement over a reasonable period of time." This allows for flexible payment arrangements, such as installment plans, to ease the financial burden on qualifying facilities.