According to Tesla's website (https://www.tesla.com/powerpack https://www.tesla.com/powerpack) each Powerpack has 50 kW / 210kWh with a scalable inverter power

According to Tesla's website (https://www.tesla.com/powerpack https://www.tesla.com/powerpack) each Powerpack has 50 kW / 210kWh with a scalable inverter power ranging from 50 kVA to 625 kVA. So they could have gotten a system with 100 MW/420 MWh