An Energy Department report recommends updating the agency’s response plans for future electricity grid emergencies and replacing transmission towers with updated equipment as ways to make Puerto Rico’s grid more resilient.

The June 20 report provides recommendations to the Puerto Rican government after Hurricanes Irma and Maria hit the U.S. territory last September, destroying the majority of the electric grid. More than 4,000 businesses and homes still lack electricity, with the 2018 hurricane season having started June...