But there was one bright spot among all of that: energy storage. The Q4 energy storage deployment reached 14.1 gigawatt-hours, up from 11.0 GWh during the same period last year. The thing is, Tesla's business spans beyond cars, AI and robotics. Its fast-growing energy business includes solar, residential Powerwall batteries and industrial-scale Megapack systems. Some of its newest Superchargers are backed by solar farms and Megapack batteries, including the massive Lost Hills, California site.