Ten microgrid systems installed in schools in Puerto Rico were put to the test recently after a 6.4 magnitude earthquake caused massive power outages. The systems survived and successfully powered critical loads in each school, according to Rocky Mountain Institute, which championed the installations along with Save the Children and the Kinesis Foundation, after Hurricane Maria. However, other issues stood in the way of taking full advantage of the back-up power—at least in the short term.
The microgrids pair photovoltaic panels with battery storage so that the schools have islanding capability (the ability to produce energy for use in the building even when the main power grid goes down). The 15–22 kW solar arrays were sized to support the critical loads of each school facility—including water pumps, communication systems, library equipment, and cafeteria appliances—and designed to allow the schools to function indefinitely even when the main power grid is out.