The scars borne by Frank van Mierlo’s small Massachusetts company, 1366 Technologies, carry warnings for U.S. companies and for the Biden climate team as it heads into the fray.

Around five years ago, tandem cells “Were not anywhere on our radar screen as a technology,” said Joseph Berry, principal scientist and hybrid solar cells team lead at the Energy Department’s National Renewable Energy Laboratory in Golden, Colo. “And they’re now one of the highest-performance … systems that we know about.” Important research, engineering and validation challenges remain to prove the technology works, first in the lab, then the field, Berry noted.

One went to 1366 Technologies to help it develop a wholly new method for producing hair-thin squares of purified silicon that are given a photo-sensitive surface to become solar cells.

The Heritage Foundation’s Nicolas Loris, testifying to a House committee in 2016, said, “If the solar company can produce a cost-competitive technology, it should not need any special government-backed loans,” and he noted its support from Hanwha, which had a $4 billion stock market valuation at the time.

Venture capitalist Carmichael Roberts, a former member of the Secretary of Energy Advisory Board, has been a key part of 1366 Technologies’ growth, first as a general partner of the company’s private backer, NorthBridge Energy Partners, then as chairman of the 1366 Technologies board.

Solar modules made with tandem sells must beat efficiencies of standard single panels by 30% with matching durability to persuade major producers to switch technologies, the French technology institute IPVF predicted in the publication Progress in Photovoltaics.

Solar projects are investment machines intended to convert sunlight into kilowatt-hours and dollars, and extremely risk-averse financial institutions don’t gamble on unproven technologies, Wesoff wrote.