At an event in Las Vegas, Tesla unveiled the next generation of its utility-scale energy storage business, revealing the new, more powerful Megapack 3, and an integrated, plug-and-play Megablock platform.
This top-to-bottom overhaul of the Megapack is designed to lower costs and accelerate deployment speed in the rapidly growing grid-scale energy market.
These announcements, which also included a new Megafactory in Houston and the decision to begin building transformers in-house help accelerate Tesla’s mission to transition the world to sustainable energy.
Megablock: A Pre-Engineered Power Plant
Megablock pic.twitter.com/JqQEAv4grj
— Tesla (@Tesla) September 9, 2025
The cornerstone of Tesla’s new strategy is the Megablock. This pre-engineered, medium-voltage building block integrates four of the new Megapack 3 units, along with a transformer and switchgear, into one single, cohesive platform. This plug-and-play approach is similar to the one that Tesla has pioneered with Superchargers, where everything is built and assembled at the factory reducing costs and installation time.
By delivering a standardized, factory-built 20 MWh block, Tesla has streamlined the entire construction process. Tesla claims that the new Megablock is 23% faster to install and results in up to 40% lower construction costs compared to traditional methods.
This speed is a game-changer, and Tesla is now actively targeting a 20-day turnaround to commission a staggering 1 GWh of storage in just 20 business days. That’s enough energy to power 400,000 homes in less than a single month, all from one single site.
That fast install isn’t the only win the Megablock is taking to the podium. It is also incredibly dense and durable. It boasts a site-level density of 248 MWh per acre, and is designed for a 25-year service life with over 10,000 cycles, all while operating at extremes between -40C to 60C (-40F to 140F).
Everything Included in the MegaBlock
At the heart of the Megablock is a completely redesigned Megapack 3. This new unit sees a 25% increase in energy capacity, jumping from 4 MWh to 5 MWh of usable AC energy in a single 28-foot-long enclosure, making it easy to ship and install.
There are various engineering improvements to the Megapack. The new thermal system is drastically simplified, leveraging a Model Y’s heat pump, but on steroids to minimize potential failure points, with 78% fewer connections. The unit itself is built around a larger battery module containing a new, larger 2.8-liter LFP battery cell, which Tesla’s own cell engineering teams helped design. A single one of these new modules weighs as much as a Cybertruck.
Installation and serviceability have also been rethought. The number of electrical connections has been reduced from 24 in the previous generation, down to just 3 simple busbar connections, alongside easier front-access to eliminate the need to climb on top of the units for service.
New Megafactory in Houston
To meet the expected and rapidly growing demand that Tesla has seen for grid-scale power, Tesla is building a new Megafactory in Houston, Texas, which will have an annual production capacity of 50 GWh. That’s a 25% increase in capacity when compared to Megafactory Lathrope and Megafactory Shanghai, both of which boast a 40 GWh annual capacity. Deliveries from this new facility are slated to begin in the second half of 2026.
In-House Transformers
Alongside all those changes, Elon also confirmed that Tesla will now begin building their own transformers in-house. These transformers are a critical component to convert power to various voltages, and are essential for industrial energy projects, often with multi-year wait times.
Yes
— Elon Musk (@elonmusk) September 9, 2025
Transformers have continued to be a bottleneck for Tesla and bringing these components in-house will let Tesla improve margins while also accelerating deployments.
All these innovations: a longer cycle life, higher energy density, faster installation, better serviceability, greater vertical integration - they’re designed to drive down the all-important metric of cost per kWh per cycle. This relentless focus on cost and efficiency is what Tesla is best known for, and it’s what makes a Megapack 3 and Megablock a killer combination for global energy grids.
