The plant went from groundbreaking to production in 16 months and is designed to build 50 GWh of Megapack 3 a year. That’s the version Tesla says packs roughly 28% more energy into the same footprint as the Megapack it replaces. Tesla confirmed the production start on Wednesday through its Megapack account, noting the Brookshire facility has “a designed capacity of 50 GWh/year dedicated to Megapack 3.” Advertisement - scroll for more contentWhat’s different about Megapack 3A single Megapack 3 holds about 5 MWh, up from 3.9 MWh on the Megapack 2 XL. Tesla just signed a $5 billion, 25 GWh Megapack deal with NatPower in Europe, and data-center operators are buying storage as fast as Tesla can build it.