Necker Island, the Caribbean Island owned by Virgin Group chairman Richard Branson, will shift to 75 percent renewable energy by the end of 2015.

Branson has struck a deal with NRG Energy to build a system that manages wind, solar and diesel power on the 74-acre island. Electricity on small Caribbean islands is extremely expensive because they must rely on imported oil to power generators.

“People no matter what socioeconomic level are paying 40 to 55 cents a kilowatt hour as opposed to in the U.S., six cents to 20 cents,” NRG Energy chief executive David Crane said. “It’s relatively easy with renewable-driven solutions to save people money because they’re paying so much.”

Branson said shifting to solar and wind energy will cut his energy costs by 40 percent. Switching to 100 percent renewables was too expensive because of the cost of storing wind and solar energy in batteries.

“I think one day, once storage is better, it could be possible to get 100 percent,” Branson said.

The project is part of the Ten Island Renewable Challenge, in which Caribbean islands will attempt to end their reliance on fossil fuels.

Branson hopes a commitment to renewable energy in the Caribbean Islands will encourage the world’s largest countries to better embrace renewable energy.

“I think it’s important that island states get their own fuel and can turn to bigger countries and say, ‘Please do something, because we love our islands; we don’t want to see our reefs destroyed or water levels rising,’ ” Branson said. “It could be a tremendous benefit to Caribbean economies, and it can save a lot of individuals quite a lot of money.”

The remote island can be booked for vacations by visitors. Google chief executive Larry Page was married on the island last summer.