Francine’s wind and rain lashed the dark neighborhoods, flooding them as Lee and Bailey almost decided to slog through hours of traffic to evacuate and stay with relatives in Texas.

Then they remembered their neighborhood church still had its lights on. Inside First Grace United Methodist Church they found an air-conditioned refuge, a place to plug in their devices. They were able to charge the breathing machine and go back to sleep in their own home.

First Grace is part of the Community Lighthouse Project, an initiative born of hurricanes, to provide essentials like functioning electrical outlets and air conditioning to people facing blackouts, by building out solar panels on church roofs. The nonprofit Together New Orleans founded the project to turn the buildings into microgrids, meaning they generate and store their own electricity when the grid is down. There are now nine operating in New Orleans with a plan to expand to 86 across the city and 500 across the state....