Apple California Flats solar farm using Tesla Megapack energy storage

In June 2020, the California Flats Solar Project filed with Monterey County, CA, an update to its environmental impact report. That updated EIR covered the proposed design for the energy storage system that Apple announced yesterday, which will add 240 megaWatt-Hours of energy storage to an existing 130 MW solar array.

A question arising from Apple’s announcement yesterday is about the ownership of the California Flats Solar Project.

The California Flats Solar Project is an LLC that was originally a subsidiary of First Solar. Apple’s portion of this project is owned by Cal Flats BESS, LLC, and Cal Flats Solar 130, LLC.

That ownership arrangement is deduced from the updated EIR filing. Namely, the entities listed as submitting the request to Monterey County to expand the project are California Flats Solar LLC; Cal Flats BESS, LLC; and Cal Flats Solar 130, LLC. There is a Wikipedia page about the project, where we learn that California Flats Solar LLC is a subsidiary of First Solar, and that the total size of the array is 280 MW. Apple’s relationship is to have a power purchase agreement worth 130 MW, and PG&E has a power purchase agreement for the remaining 150 MW of capacity.

Hence, Cal Flats Solar 130 refers to Apples 130 MW chunk of the project, and Cal Flats BESS refers to the energy storage system.

The California Flats project was originally approved in February 2015, and the corresponding planning projects can be found on the County of Monterey website.

The site is near Parkfield, and can be easily inspected on your favorite online map service. It is 2,120 acres acres of land leased from The Hearst Corporation. The existing project is 1,684 acres including the solar array and a substation. There is a PG&E transmission line running through the center of the project.

The new energy storage project requires a 3-acre pad to house the energy storage array, and an addition to the existing substation.

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The energy storage array will be 85 Megapack modules. Each group of four Megapack battery units would be installed on an approximately 75 foot long by 12 foot wide by two foot thick concrete pad.

This is the overview of the project to add an energy storage array to the California Flats project. The actual solar array is located to either side of what’s shown here.

Apple’s announcement yesterday made it sound like Apple owned the California Solar Flats Project outright. Instead we learn that their involvement is with a power purchase agreement. That in turn raises a question whether Apple will own the energy storage unit, or whether it is instead owned by a 3rd party with whom Apple has a power purchase agreement.

Another question has to do with the optics of Apple buying energy storage systems from Tesla. Both companies have top expertise in battery management systems. However, Apple’s expertise is with batteries for tiny devices like laptops and tablet computers, while Tesla’s expertise is with large battery systems for cars and for fixed installation alongside solar arrays.

H/T TheVerge for finding the EIR

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About David Herron

David Herron is a writer and software engineer living in Silicon Valley. He primarily writes about electric vehicles, clean energy systems, climate change, peak oil and related issues. When not writing he indulges in software projects and is sometimes employed as a software engineer. David has written for sites like PlugInCars and TorqueNews, and worked for companies like Sun Microsystems and Yahoo.