But he cautioned that a battery’s cost per kilowatt-hour depended on the application and scale. And he said the company’s technology would have to live up to scrutiny. “People do make claims and offer what they feel like is a legitimate set of data,” he said. “I’m always elated to hear progress in storage, but you have to be careful.”

Batteries are not the only form of energy storage that the power industry is pursuing. Other technologies include compressed air in caves and the long-used pumped hydroelectric plant storage. The Los Angeles Department of Water and Power is proposing to turn Hoover Dam into a type of giant battery to manage excess solar and wind electricity at a cost of $3 billion.

Lyndon Rive, a co-founder of SolarCity — now a part of his cousin Elon Musk’s company, Tesla — said recently that solar and storage innovations were likely to transform the electricity market. “Over all, the trajectory is for solar to be the No. 1 source,” said Mr. Rive, who left Tesla after the two companies merged two years ago.

Dr. Soon-Shiong said he knew Mr. Musk — a fellow South African native — and considered him a visionary for his accomplishments in electric vehicles and energy storage. “We both are trying to make the world a better place,” Dr. Soon-Shiong said.

Tesla has based its businesses on lithium-ion technology, and Mr. Musk has told shareholders that the company may get the cost of lithium-ion cells down to $100 a kilowatt-hour this year.

NantEnergy made its announcement weeks after California mandated 100 percent carbon-free electricity in the state by 2045. Legislators have also approved a bill providing about $1 billion in subsidies for residential energy storage.

“California is obviously in need of that kind of breakthrough to meet our goals,” said Bernadette Del Chiaro, executive director of the California Solar and Storage Association, a trade group. “I cannot claim to be in absolute certainty that this is everything they say it is, but it’s exciting. It’s this kind of breakthrough that we expect from our innovators.”