Platts proposes to launch US PPA price assessments for long-term solar contracts in MISO, SPP power hubs

Platts, part of S&P Global Energy, is proposing to launch daily Power Purchase Agreement (PPA) price assessments for long-term solar contracts in the Midcontinent Independent System Operator (MISO) and the Southwest Power Pool (SPP), effective Aug. 24, 2026.

These assessments would focus on PPA prices for physical and virtual long-term contracts for electricity power generated from solar projects across three hubs in MISO and two hubs in SPP. Platts defines long-term as PPAs for a tenure of 120 months or longer. On Jan. 1, the long-term contracts would roll forward to the following year. For example, on Jan. 1, 2027, Platts would start assessing tenors from January 2028.

The published values would reflect virtual PPAs, financially settled, as the basis. Platts would normalize all PPA data to this standard for assessment purposes.

The proposed assessments are listed below:

• MISO Indiana Hub Solar Long-Term As-Generated PPA Index
• MISO Arkansas Hub Solar Long-Term As-Generated PPA Index
• MISO Illinois Hub Solar Long-Term As-Generated PPA Index
• SPP North Hub Solar Long-Term As-Generated PPA Index
• SPP South Hub Solar Long-Term As-Generated PPA Index

These price assessments would also reflect PPA projects for solar technology with an electricity generation capacity of at least 75 megawatts (MW), and contracted on an as-generated basis with a timestamp of 1330 CT. These assessments would be published in US dollars/mega-watt hour (MWh) and follow the US holiday calendar.

The long-term solar assessments would be assessed as bundled products, reflecting energy and Renewable Energy Certificates (RECs) together.

Platts would consider bids, offers, trades, and indicative values for PPAs using these specifications.

Platts would also publish monthly averages for the assessments listed above.

Please send any questions or comments to powerpricing@spglobal.com and pricegroup@spglobal.com by July 24, 2026.

For written comments, please provide a clear indication if comments are not intended for publication by Platts for public viewing. Platts will consider all comments received and will make comments not marked as confidential available upon request.