Inside a shipping container currently en route to a school in Puerto Rico, a solar microgrid is ready for deployment: As soon as the container arrives, the system, from a startup called BoxPower, can be assembled and begin providing power in less than a day. The system, designed for use both immediately after disasters and to make communities more resilient to future disasters, is easy to rapidly install. The first product fits inside a standard 20-foot shipping container, so it can easily be transported. Inside, there are solar panels and racks, along with a prewired battery, inverter, and a backup generator that runs on fossil fuels, so it can still be used if there’s ever a series of cloudy days and the battery runs low. The system can provide around 50 kilowatt-hours of electricity, or enough to power three or four homes or an energy-intensive business, the company says. If a disaster is imminent the whole can be quickly disassembled and packed back inside the shipping container.