What if an entire isolated community received all of its power needs from the sun? A remote island off of Africa is about to find out — and the project could be a game changer for solar.

“Ninety-nine percent of solar projects have solar panels dumping [all of their power] into the grid,” Darren Hammell told VentureBeat. He’s co-founder and Chief Strategic Officer of Princeton Power Systems, which, along with GE Power & Water and MAECI Solar, has been chosen by the national government of Equatorial Guinea to build a five-megawatt solar microgrid for the island.

This streaming power mode has been one of the chief criticisms of solar power – it generates electricity only when the sun is shining, and the power plant-fed grid must still be used when the sun’s not available.

“In this case,” he said, “it’s an island, so there’s no [electrical] grid” to feed or use as backup at night or on cloudy days. To handle those needs, the microgrid will store its excess in banks of GE Durathon batteries.

The island off of west central Africa, Annobon, has 5,000 inhabitants but only trickles of power — less than five hours daily for most residents, who must spend as much as 20 percent of their income on supplemental electricity. This is only a drop in the bucket, since more than half a billion people in Africa have no electricity.

But the microgrid, which is expected to be finished by early next year, points to a solution. It will feed clean power to the entire island, be reliable, and take care of 100 percent of the residents’ needs.

“It’s not the first time” a solar grid has stored a large part of its power, Hammell said, “but [it is the first time] at this scale and cost.” The grid is expected to generate power at a cost about 30 percent less per kilowatt-hour than diesel fuel, the island’s previous power source.

It will also be the largest self-sufficient solar project on the continent. “We’ve heard numbers that the market for this kind of system across Africa is tremendous,” he said, “dwarfing anything done so far.”

Hammell said this approach could also be used in developed markets, where 60 to 70 percent of power needs could be generated by solar, the rest met by the electrical grid, and batteries used as backup.

“But in a developed country, you have a very reliable [electrical] grid,” he said, so there’s no need to go completely off of the electrical grid.