While Tesla's solar roof / Powerwall event isn't until tomorrow, the product that preceded both, its commercial... cousin, Powerpack, has been upgraded and is already shipping to companies. The company says Powerpack 2 has double the energy density than the original model, paired with a new inverter (made at its Gigafactory), that's apparently the lowest-priced, highest efficiency utility-scale inverter available. Arguably just as important, the new inverter also simplifies the installation process, with several once-separate components now baked into it.