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. Reflects the average percentage of power available over the previous 12 months, weighted by GWh for projects that have contracted an Availability Guarantee and been in operation for over 30 days. At an event in Las Vegas on the margins of the RE+ renewable energy convention, Tesla. When Tesla unveiled its next-generation energy storage systems—Megapack 3 and the new Megablock—on September 15, 2025, it marked a pivotal moment in the evolution of utility-scale battery energy storage. 9 MWh of energy, sufficient to power approximately 3,600 households for one hour.
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