MISO Resource Adequacy Needs and Impacts of the Proposed ERAS Process
Prepared for NextEra Energy Resources
This report, “MISO Resource Adequacy Needs and Impacts of the Proposed ERAS Process,“ was prepared for NextEra Energy Resources by Principal Michael Hagerty, Associate Christa Shen, and Senior Energy Specialist Evan Bennett.
On March 17, 2025, Midcontinent Independent System Operator (MISO) filed with the Federal Energy Regulatory Commission (FERC) an updated tariff that includes a process for expediting resources through the interconnection process. The expedited process, known as the Expedited Resource Addition Study (ERAS), will be available for resources identified by state utility commissions and other Relevant Electric Retail Regulatory Authorities (RERRA) as necessary to meet a resource adequacy or reliability need claimed by the RERRA, a load-serving entity (LSE), or interconnection customers.
In its FERC filing, MISO specifically refers to two recent surveys and studies completed in 2024 to support its need for implementing the ERAS approach: the Organization of MISO States (OMS)-MISO Survey and the North American Electricity Reliability Corporation (NERC) Long Term Reliability Assessment (LTRA). Both assessments of MISO resource adequacy identify a need for a significant increase in resource additions in future years.
Brattle experts have reviewed MISO data and find that the need is overstated for two primary reasons. First, MISO’s updated load growth projections and accreditation approach tend to reduce the identified need. Second, neither study considers the full set of resources that could come online to meet future MISO resource adequacy needs through 2030, nor the recent increase in the rate of MISO capacity additions in 2023 and 2024.
