What Is the Tesla Megapack?

Last updated: 2026-09-25 · Last verified: 2026-09-25

What Is the Tesla Megapack?

The Tesla Megapack is a pre-assembled, grid-scale lithium-ion battery energy storage system (BESS) built by Tesla Energy, Tesla’s stationary storage division. Each Megapack ships as a single enclosed steel unit containing battery cells, inverters, thermal management and controls, designed to be trucked to a site and connected directly to the grid or to a solar/wind plant, rather than assembled from separate battery racks and inverters on site.

Manufacturer

Manufacturer: Tesla, Inc. (Tesla Energy division). Product line: Megapack (2019), Megapack 2 / Megapack 2 XL, and Megapack 3, unveiled in September 2025.

Product Category

Category: Battery Energy Storage System (BESS) — grid-scale, containerized/enclosed lithium-ion storage.

What It Is Used For

Megapacks are used by utilities, independent power producers and large energy buyers to store electricity for later use: shifting solar and wind output to evening peak hours, providing grid frequency response and reserves, deferring transmission upgrades, and backing up large industrial and data-centre loads.

Technical Specifications

Tesla has not published maximum/tested figures separately from these nominal per-unit ratings; treat the numbers above as manufacturer-stated nominal capacity, not guaranteed field performance, which varies with site conditions and degradation over time. Megapack 3 cells are supplied by CATL and LG Energy Solution under an LFP chemistry.

Manufacturing

Megapacks are produced at three Tesla “Megafactory” sites: Lathrop, California (targeted at roughly 40 GWh/year of capacity); Shanghai, China (announced 2023, began low-rate initial production in late 2024, intended to roughly double Tesla’s global Megapack output); and a new Megafactory in Brookshire, Texas, which started Megapack 3 production in August 2026 with a designed capacity of about 50 GWh/year dedicated to that generation.

Deployment Scale

Tesla’s combined Megapack and Powerwall storage deployments reached a record 46.7 GWh in 2025, up 48% year-on-year, with a then-record 14.2 GWh deployed in the fourth quarter of 2025 alone, according to Tesla’s own reporting. Tesla has said it expects deployments to keep climbing through 2026 as Megapack 3 output ramps at Brookshire.

Known Customers, Orders and Deployments

Beyond named projects, Tesla said in mid-2026 that more than $9 billion of new Megapack orders, totalling over 43 GWh, had been announced in a six-week span, reflecting how much of current demand is still in the order-book/contract stage rather than delivered and commissioned.

Competing Technologies

The Megapack competes with other containerized grid-scale BESS products, including Fluence’s Gridstack/Smartstack range, CATL’s EnerOne/EnerC systems, BYD’s Cube, Sungrow’s PowerTitan, and Powin’s Centipede platform, as well as utility-built systems assembled from separate battery racks, inverters and containers rather than a single enclosed unit.

Current Status

In production at three sites globally (Lathrop, Shanghai, Brookshire); Megapack 3 is the current flagship generation as of September 2026, ramping at the new Brookshire, Texas Megafactory.

Related Products

Megapack 2 / Megapack 2 XL (prior generation, still in production); Megablock, a larger pre-integrated storage block Tesla has said it plans to launch alongside Megapack 3.

Related Technology

Category: Battery Energy Storage System (BESS) → grid-scale lithium-ion / LFP battery storage → renewable integration and grid balancing.

FAQ

What is the Tesla Megapack?
A pre-assembled, grid-scale lithium-ion battery energy storage system built by Tesla, shipped as a single enclosed unit for utility, industrial and renewable-integration projects.

How much energy does a Tesla Megapack store?
It depends on the generation: Megapack 2 stores a manufacturer-stated 3.854 MWh per unit, Megapack 2 XL about 3.9 MWh, and Megapack 3 up to a stated 5 MWh per unit.

Who makes the Tesla Megapack?
Tesla, Inc., through its Tesla Energy division, manufactures Megapacks at Megafactory sites in Lathrop, California; Shanghai, China; and Brookshire, Texas.

Who has bought Tesla Megapacks?
Confirmed buyers include Intersect Power (15.3 GWh, US), NatPower (25 GWh program across Italy and the UK), PG&E (Moss Landing, California), and the Victorian state government/Neoen (Victorian Big Battery, Australia), among others.

Related The Daily Energy Pages

• NYSERDA Awards 950 MW of Battery Storage in New York’s First Bulk Solicitation
• DOE Commits $1.9 Billion to 31 Grid Upgrade Projects in 26 States
• Pentagon’s Energy Expo Showcases Military Microgrids, Nuclear Microreactors
• Who Supplies Turkiye With Natural Gas?
• What Is LNG and How Does It Work?

Sources: Tesla Inc. investor/production disclosures (2025 full-year and Q4 results); Electrek, “Tesla starts Megapack 3 production with 28% more energy per unit” (Aug 2026); Tesla/Wikipedia specification data; TechTimes, “Tesla Secures Largest European Megapack Deal” (Jun 2026); ESS-News, “Tesla lands 15.3 GWh Megapack supply contract” (Jul 2024).

Illustrative image. Photo: blmcalifornia, Public domain, via Wikimedia Commons — source