California ISO files interconnect deal for Mesquite Solar 3 project

The California Independent System Operator filed on April 29 at the Federal Energy Regulatory Commission an executed Large Generator Interconnection Agreement with San Diego Gas & Electric and with Mesquite Solar 3 LLC, SEP II LLC and SGS Development LLC as interconnection customer co-tenants.

The Mesquite Solar 3 LGIA is a non-conforming LGIA, which provides for the interconnection of the Mesquite Solar 3 solar photovoltaic generating facility located in Maricopa, Arizona.

Mesquite Solar 3 will utilize an existing interconnection comprised of two 500 kV generation tie lines between the Hassayampa Switchyard and the Mesquite 230/500 kV Switchyard. In the discussions leading to the Mesquite Solar 1 LGIA, the CAISO and Salt River Project Agricultural Improvement and Power District (SRP) concluded that the existing Common Bus arrangement permits the CAISO to receive the power output of Mesquite Solar 1 or other similarly situated generating facilities, such as Mesquite Solar 2 and Mesquite Solar 3, without requiring tagging.

The Mesquite Solar 3 project is comprised of 202 Toshiba Mitsubishi Electric Industrial Systems Corp. inverters each rated at 1.833 MW. Since the capability of these inverters is greater than the maximum capacity of the Large Generating Facility approved by the CAISO in the Phase II Study Report, the project developer has agreed to provide a mechanism by which it will limit the generator output at the Large Generating Facility (gross output) to the approved MW capability of 370 MW. It may elect to downsize the project in the future pursuant to the applicable CAISO process.

The targeted commercial operation date is Nov. 30, 2019.

A project contact is: Mesquite Solar 3 LLC, c/o David Grazda Director-Asset Management, Sempra U.S. Gas & Power LLC, 488 8th Avenue, HQ11S3 San Diego, CA 92101, Phone (619) 696-4480,

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.