Ellsworth Energy Storage, LLC Seeks Exemption from FERC Wholesale Generator Regulations

Strategic Insights -

Ellsworth Energy Storage, LLC, a Delaware limited liability company, has submitted a self-certification notice to the Federal Energy Regulatory Commission (FERC) seeking exemption from wholesale generator regulations as an exempt wholesale generator (EWG). The notice states that Ellsworth will own and operate a 350 MW battery energy storage system in Maricopa County, Arizona, and will interconnect with the Salt River Project Agricultural Improvement and Power District (SRP) transmission system. The facility will sell electric energy, capacity, and ancillary services at wholesale, and will engage in incidental activities such as trading emission allowances and selling "green" power certificates or credits.

Key Takeaways:

  • Ellsworth Energy Storage, LLC has submitted a self-certification notice to FERC seeking exemption from wholesale generator regulations as an EWG.
  • The facility will own and operate a 350 MW battery energy storage system in Maricopa County, Arizona, and will interconnect with the SRP transmission system.
  • The facility will sell electric energy, capacity, and ancillary services at wholesale, and will engage in incidental activities such as trading emission allowances and selling "green" power certificates or credits.
  • The facility will be represented by Senior FERC Counsel William Lavarco of NextEra Energy Resources, LLC.
  • Ellsworth is a wholly owned, direct subsidiary of ESI Energy, LLC, which is a wholly owned, direct subsidiary of NextEra Energy Resources, LLC.
  • The facility will not own or control transmission facilities or interconnection facilities other than those necessary to connect the facility to the transmission system.
  • Ellsworth will certify that it satisfies the requirements for EWG status, including that it will be engaged directly and exclusively in the business of owning and operating the facility and selling electric energy at wholesale.
  • The facility will comply with FERC regulations and guidelines, specifically Section 366.7 of 18 C.F.R., which specifies the requirements for EWG status.

Statistics:

  • The facility will have a capacity of 350 MW.
  • The facility will sell electric energy, capacity, and ancillary services at wholesale.
  • Ellsworth Energy Storage, LLC is a subsidiary of NextEra Energy Resources, LLC.
  • The facility will interconnect with the SRP transmission system.
  • The facility will engage in incidental activities such as trading emission allowances and selling "green" power certificates or credits.
  • William S. Lavarco is the Senior FERC Counsel representing Ellsworth Energy Storage, LLC.
  • The facility will be built in Maricopa County, Arizona.
  • Ellsworth is seeking exemption from FERC wholesale generator regulations.

Sources:

  • Ellsworth Energy Storage, LLC (Notice of Self-Certification of Exempt Wholesale Generator Status of Ellsworth Energy Storage, LLC, August 4, 2025)
  • 18 C.F.R. § 366.7 (2024)
  • NextEra Energy Resources, LLC (Representation in Notice of Self-Certification of Exempt Wholesale Generator Status of Ellsworth Energy Storage, LLC, August 4, 2025)