Tesla unveils Megablock consisting of 4 Megapack 3 with transformers and switchgear

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= more power and energy deployed faster

Fred Lambert | Sep 8 2025 – 8:54 pm PT

Tesla has unveiled two new energy storage products: Megapack 3, the latest generation of its utility-scale energy storage system, and Megablock, which integrates Megapack 3 with transformers and switchgear.

At an event in Las Vegas on the margins of the RE+ renewable energy convention, Tesla unveiled its latest generation of large-scale energy storage products.

As expected, Tesla unveiled Megapack 3, the latest generation of its biggest stationary energy storage battery system.

The company is now using bigger 2.8-liter battery cells, resulting in a higher energy capacity: roughly 5 MWh compared to 3.9 MWh for Megpack 2.

Tesla also significantly simplified the thermal bay, reducing the number of connections by 78%.

However, the more significant product unveiled by Tesla today is the Megablock, which combines four Megapack 3s directly connected to a megavolt transformer and switchgear.

This is what it looks like:

Tesla claims 23% faster installation time with more of the assembly being done in a factory setting rather than on-site.

Mike Snyder, Tesla’s VP of energy and charging, claimed that Tesla can deploy 1 GWh in 20 business days with this new Megablock configuration.

The company also claims a higher energy density at the site: 248 MWh per acre.

Snyder said that Tesla plans to build Megapack 3 in Houston starting in late 2026. We learned in March that Tesla was building a new Megafactory in Houston.

The energy executive stated that the factory would have a capacity of 50 gigawatt-hours (GWh) per year.

Electrek’s Take

This sounds like a strong incremental improvement to an already popular energy storage product.

Top comment by Aaarrrgggh

 Liked by 25 people

Actually the biggest improvement is really factory integrating four units with a transformer. The Megapack 2 was really a bust on that front, requiring much more field wiring than it should have. This means that almost all of the field connections are medium voltage and hopefully you can run about 4-6 blocks per circuit to really speed up work.

The battery cells are part of the equation, but they aren’t what really makes the system work. The software is non-trivial.

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However, the new battery cells are probably the biggest part of the improvement and Tesla doesn’t manufacture those.

In fact, Tesla’s battery cell suppliers BYD and CATL, both have battery systems that compete with Tesla’s Megapack, which could prove problematic for Tesla in the near future.

I think Tesla’s strongest energy storage product is probably its Autobidder software. It optimizes energy storage products like nothing else. It would do well to keep licensing this to other energy storage systems.

Tesla’s next biggest advantage is the complete integration of energy storage, power electronics, software, and service. It makes for an attractive turnkey solutions for utilities and large-scale projects, like AI data centers.

Dutch Lion Storage, project Mufasa – one of the largest battery energy storage systems (BESS) in the Europe – has reached Financial Close.

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Project Mufasa will feature Megapack 2 XL, Tesla’s utility scale energy storage system. The batteries will be able to charge and discharge 1,400 MWh at 350 MW power capacity, several times per day: sufficient to power well over 200,000 households.

Set to become operational in H1 2027, the project is being built in Vlissingen in North Sea Port, a key hub for renewable energy in the Netherlands. Replacing a former coal-fired power plant connection to the high voltage grid, this landmark initiative represents a major step forward in supporting the Netherlands’ transition to renewable power, while strengthening its critical energy infrastructure.

Project Mufasa will feature Megapack 2 XL, Tesla’s utility scale energy storage system. The batteries will be able to charge and discharge 1,400 MWh at 350 MW power capacity, several times per day: sufficient to power well over 200,000 households. As the largest BESS in the Netherlands and one of the largest energy storage projects in Europe, it sets a new standard for balancing and securing power grids.

CETECO Energy

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BESS Energy Storage Systems

40ft LFP 2500 – 5000 kWh containers

  • 2,500 kW – 5,000 kW capacity
  • Lithium-Ferro-Phosphate battery with module efficiency 92% – 94%,
  • plug & play system, including battery management system,
  • Inverter technology “Made in Germany”,
  • technical documentation,
  • 40 ft insulated battery container, colour: grey, RAL 701 produced in Germany.
  • Warranty: 10,000 cycles or 15, depending on the intensity of use,
  • 15 years manufacturer’s warranty by a well-known German insurance group
  • active thermal management (cooling in summer & heating in winter),
  • TÜV approval & load test before delivery with data sheet,
  • Battery Management Training

Transformers

The main bottleneck in producing these large batteries is the availability of transformers and the long delivery times due to a lack of transformer production capacity.

We secured the delivery of Chinese electrolytes & transformers from our Chinese partner, which can be delivered to Kiel within a 4-month delivery notice.

Info; beelaerts@cetecoenergy.com