Stephen Crane, CEO of LightSail Energy, at the company's Berkeley headquarters

James Temple, Re/code

Stephen Crane, CEO of LightSail Energy, at the company’s Berkeley headquarters

Science


LightSail Energy has appointed two industry veterans to its executive ranks, as the energy storage startup looks to ramp up sales of its technology.

It represents a new phase and test for the five-year-old company, which has attracted media interest and heavyweight backers but has yet to really test the market appetite for its new twist on the old idea of compressed air.

The Berkeley business will announce Tuesday morning that Volker Schulte, a former General Electric executive, has been named chief operating officer and Neel Sirosh, previously chief technology officer at Quantum Technologies, will serve as vice president and general manager of the energy storage team.

LightSail co-founder and chief executive Steve Crane said their backgrounds will be critical as the company — which has raised nearly $58 million from Khosla Ventures, Peter Thiel, Bill Gates and others — shifts from prototype development to full-blown manufacturing.

“We felt that we were at the point where we’ve really proved out the technology at scale,” Crane said in an interview last week. “But it’s still a long way to a product you can stamp out at low cost. Volker and Neel both bring in the sort of discipline and experience needed to really design products that can be mass-produced efficiently.”

But why compressed air?

Fossil fuels like gas and coal store energy in their natural forms, but renewables such as solar and wind power don’t have that luxury. When the sun is shining or wind is blowing, you can either use the energy, lose it or devise a way to store it.

But the options within that last bucket are limited. There are batteries that are expensive and rapidly degrade. Or there’s pumped-storage hydroelectricity, where excess energy is used to move water from a lower reservoir to a higher one. That energy can be reclaimed later when the water is allowed to flow back downhill through a turbine.

On the whole, it’s cheaper than batteries, but the downside is that it only works where you happen to have the geography to accommodate two reservoirs at differing heights.

So as a practical matter, renewables are generally used to supplement fossil fuels, taking pressure off the grid during peak hours.

But few areas can rely on them entirely because of their intermittent nature. And there’s a limit to the amount that can be hooked up to the grid without potentially destabilizing it. Add too much solar to the current infrastructure and power companies have to regularly and rapidly fire up fossil fuel plants to offset the big downswings when the sun begins to dip, Crane said.

Cheaper and more flexible storage could begin to change that, enabling renewables to become a bigger and more dependable part of the overall energy equation.

Which gets us back to compressed air.

“It’s a natural mate for renewables; it turns an unpredictable source into a dispatch-able source,” Crane said. “It’s available on demand.”

Engineers have known for more than a century that you can use electricity to force air into a tank, and tap that energy again by reversing the process. The problem is the air gets super hot in the process and much of the heat energy dissipates while in storage.

LightSail’s trick, credited to co-founder and chief scientist Danielle Fong, is adding a mist of water during the air compression process. Instead of shooting up by more than 1,000 degrees Celsius, the temperature climbs by about 20 degrees.

It’s easier to retain that increase and, in turn, reclaim a bigger portion of the energy as it exits the pressure vessels. At least theoretically, LightSail will be able to hold on to about two-thirds of the initial energy, up from about 35 percent with the conventional method.

That means they can approach the energy storage efficiency of batteries at the price of pumped hydro, at least if everything works according to plan.

“The nice thing is it’s clean and it’s cheap,” Crane said. “Our working materials are air and water.”

But the company faces some challenges as well.

First off, LightSail is hardly alone in tackling the energy-storage conundrum. General Compression and SustainX are both pursuing their own approaches to compressed air.

Meanwhile, other businesses are exploring novel ways of getting more out of batteries, whether for the grid or gadgets, including Ambri, which is employing liquid metal, and Amprius, which is exploring silicon. If batteries can be made cheaper and more efficient, they hold at least one big advantage over compressed air: They’re far more portable and flexible than the shipping-container-sized systems LightSail is building.

Finally, it’s no easy task to burst into the tightly-regulated energy market, despite obvious inefficiencies and the dire need to shift to sustainable systems amid worsening prospects for climate change. The deep-pocketed incumbent players have a lot to lose, and have proven adept at protecting the status quo.

So who’s buying?

Though other deals have occurred, only one has been officially announced to date. Last year, the California Energy Commission revealed a $1.7 million energy research project for a U.S. Navy base in Ventura County, Calif., with Foresight Renewable Solutions of San Francisco. LightSail will provide the compressed air technology.

The company expects other early customers to be isolated regions on islands or developing nations, specifically areas disconnected from the grid and reliant on things like diesel generators. They’re also looking to serve conventional wind and solar farms, enabling them to save energy on site. Other customers could include large-scale industrial companies that will want to generate, store and use renewable energy to lower costs.

Regulations will have to change before these customers would be able to feed power from LightSail storage back into the grid. But that’s the eventual hope.

LightSail’s new COO Schulte, who left the stability of GE’s gas engine business to join the startup, said he saw it as a unique opportunity to help push forward sustainable energy.

“Energy storage is a problem that really hasn’t been solved to date,” he said. “In order to make renewable energy a capable and integrated part of the mainstream landscape, storage is really the missing link.”