Tesla details plan to build one of the biggest batteries in the world

The company is bidding on a project in Hawaii.


Tesla is bidding to build one of the world's largest batteries, planning documents reveal.

The company has outlined plans to build 244 Megapacks in Hawaii, each with around three megawatt-hours of capacity, to offer 810 megawatt-hours of total storage. Electrek reported Sunday that the project will discharge energy at a rate of 135 megawatts.

If it comes to fruition, it could rank as one of the largest batteries in the world and maintain Tesla's status as a key player in energy storage. While the company is best known for its all-electric vehicles, Tesla uses the same cells to supply homes and businesses with the Powerwall, Powerpack and Megapack. Combined with renewable energy sources like the Tesla Solar Roof, an installation can provide 24-hour clean energy and aid the transition away from carbon-emitting fossil fuels.

It's all part of CEO Elon Musk's broader goal with Tesla, to transition the world away from fossil fuels. During the company's June 2019 earnings call, Musk called for "Terawatt-hour" levels of battery production, which would provide the capacity to transition more people onto cleaner energy.

Hawaiian Electric, which serves 95 percent of the state, has been taking bids for the proposed project since last summer. The battery would be situated on the island of O'ahu at Kahe Power Plant. It will work with a 390-megawatt-hour project near Kalaeloa to help retire the coal-fired plant set to close in 2022. These are two of five energy storage projects the company is considering.

The project is aimed at two goals. The first is load-shifting, where energy is stored during low demand and sent out during high demand to ease pressure on the grid. The second is as a backup, to protect against drops in energy production and fill the gap.

The project as outlined in the documents.

Hawaiian Electric

The electric company's project description explains how it will set up the batteries:

Each Megapack is equipped with (Figure 2.1): (i) liquid-cooled lithium-ion batteries for energy storage; (ii) a circuit breaker panel/customer interface bay; (iii) DC-to-DC converter units to step up the voltage; (iv) a 675 kVA inverter that converts DC stored in the battery to AC used on the Company grid; and (v) a thermal management system. The equipment is packaged as a single unit in a shipping container- type housing referred to as the IP66 enclosure. Four Megapacks are grouped together.

Further down the document, Hawaiian Electric explains that the option will remain in the future to augment these Megapacks with smaller Powerpacks to boost overall capacity.

The Megapack is a relatively new offering from Tesla, first unveiled in June 2019 as a means of offering 60 percent greater energy density than the Powerpack. These Megapacks are aimed at grid-scale storage, similar to the Powerpack, and stand in contrast to the consumer-focused Powerwall. Tesla announcef the Megapack with the claim it could deploy one gigawatt-hour over three aces in less than three months, around foru times faster than a similarly-sized fossil fuel plant.

The Hawaii project would far outrank the company's project in South Australia, described as the world's largest lithium-ion battery when completed in November 2017. The Australia project in Hornsdale measured 129 megawatt-hours at launch, but in December 2019 was expanded by a further 64.5 megawatt-hours to reach 193.5 megawatt-hours total.

But while the Hawaii project will far outrank the Hornsdale project, it will likely miss the title of world's largest battery. The Florida Power & Light Company announced in March 2019 plans to install 900 megawatt-hours over 40 acres. Described by the firm as "the world's largest solar-powered battery," it's set to start providing power in late 2021.

Hawaiian Electric is set to hold a series of virtual meetings to seek public input on the projects. Comments on the five proposals will be accepted until May 2020.

Update 30/03 8:40 a.m. Eastern time: An earlier version of this article stated Tesla aims "to transition the world toward fossil fuels." It has since been corrected.

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