Expect to see a lot more solar rooftops in Florida.

The Sunshine State is removing a roadblock to consumer solar leasing, an arrangement that drove a boom in U.S. rooftop power systems. The decision will let Sunrun Inc., the largest U.S. residential-solar company, expand in the state.

Utilities are the only entities that can legally sell electricity in Florida. Sunrun challenged an interpretation of that policy and the Florida Public Service Commission ruled that the company’s 20-year solar-equipment leases don’t...