Solar power in New York City may finally be having its moment.

The number of residential projects across the five boroughs has risen to more than 5,300 this year from 186 in 2011, according to state officials, and there are another 1,900 in the pipeline. The solar boom has been prompted by a 70 percent drop in installation costs in recent years, according to the Solar Energy Industries Association, along with the streamlining of government approvals and incentives.

The upfront cost for installing solar panels on a single-family house runs between $20,000 and $50,000, but federal, state and city incentives and tax credits can cut that cost in half, said David Sandbank, the director of the New York State Energy Research and Development Authority’s NY-Sun initiative, and homeowners say that once solar panels are up and running, monthly energy bills can fall by as much as 85 percent.

Most of the city’s existing solar projects are on single-family houses on Staten Island, but townhouse owners in Brooklyn are getting on board, and owners of apartment buildings in the Bronx and Queens are also starting to consider ways to harness the sun’s power.

The solar industry itself has surged. According to the city’s Economic Development Corporation, five solar installers were operating in the five boroughs in 2005, but by 2015, the number had increased to about 55 companies, employing about 2,700 workers.