The rebuilding and hardening of Puerto Rico’s electricity grid in the seven months since Hurricane Maria hit the island has prepared it to weather future storms, the Energy Department’s top electricity official told Bloomberg Environment.

That’s in spite of this week’s 24-hour, contractor-caused blackout on the island.

The Puerto Rico Electric Power Authority (PREPA) reported April 19 that power was restored after the blackout, which occurred after a private contractor cut the main transmission line while removing a collapsed tower....