A Heliogen solar thermal facility in Lancaster is spread over two acres.

A Heliogen solar thermal facility in Lancaster is spread over two acres.

The device increased the panels’ efficiency by about 30%. Gross said Edisun Microgrids is still operating, though he declined to give information on the number of customers or annual revenue.

“That technology evolved, and we were able to place trackers in mirror arrays to track the sun throughout the day,” Gross said. “That has greatly increased the efficiency of those mirrors and allows us to concentrate solar heat at much higher temperatures, roughly twice as hot as in previous solar thermal arrays.”


Bill Gross, Heliogen founder and CEO

The mirrors focus solar energy on a central tower, ranging from 50 feet to 150 feet in height, that contains the substance to be heated.

Heliogen is partnering with Centreville, Va.-based Parsons Corp. to design and construct the array assemblies. (Parsons was headquartered in Pasadena until February and retains a sizeable workforce there.)

Solar thermal troubles

Until now, solar arrays that generate heat by concentrating sunlight have been focused on generating electricity because they can only heat a substance to about 600 degrees Celsius (1,100 degrees Fahrenheit).

The substance of choice has been salt, which turns molten and then can be used to heat water and turn that water into steam to power turbines and generate electricity. Santa Monica-based SolarReserve Inc. has been one of the main developers of this technology.

These types of projects have encountered difficulties recently as the plunging cost of solar photovoltaic panels has made solar thermal plants less cost-competitive.

SolarReserve this year scrapped scheduled projects in Australia and Nevada.

Heliogen, though, is not in the business of generating electricity, so it doesn’t face competition from photovoltaic panels. It heats other substances directly, allowing them to transform into usable products such as cement and steel.

But Heliogen faces challenges of its own. First is the acreage and sunny locales needed for the mirror arrays. The Lancaster test facility has about 400 mirrors spread over two acres; at least initially, arrays for future customers would have to be similar in size, which means industrial plants that would use this technology can’t be in dense urban or even suburban areas.

Then there’s the cost. Gross said each array and tower assembly will run between $10 million and $100 million, which means only highly capitalized companies can afford the technology.

Most likely, Gross said, companies will opt to lease the technology at a cost starting around $250,000 per month.

Gross said many major industrial plants spend more than $300,000 a month on fossil fuels to provide the intense heat they need for their manufacturing processes, so this technology could run about 20% cheaper.

But analyst Molchanov said the economics of Heliogen’s offering remain a question.

“Can this technology be viable in places that have moderate amounts of sunlight, such as New York or Germany?” Molchanov asked. “And at what natural gas price would Heliogen’s energy output be cost-competitive?”

The answers could come on a case-by-case basis, he said. That, over time, will determine whether Gross’ bold venture will pay off.


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