The amount of battery capacity required to sustain power demand for this to be scaled to a meaningful population is high (PR average daily power demand is ~50 GWh per day). Most power outages in PR take 48 to 72 hours to fix. You would need batteries that can store 150 GWh of power. That’s a LOT of money to install.

Even this assumes that you wouldn’t want any breathing room on battery capacity (i.e., every power outage will be fixed in under 72 hours).