Undeterred by the bankruptcy filing of a California solar company that got $535 million in federal loan guarantees, the Energy Department is issuing two more large loan guarantees, albeit to companies that look like safer bets.

The department will announce Thursday that it has completed a $150 million loan guarantee to 1366 Technologies, a company with a new way to make the silicon wafers used in solar cells. The company, based in Lexington, Mass., is the star pupil of the department’s Advanced Research Projects Agency — Energy, or ARPA-E, which makes grants to entities with radical ideas with great potential value; 1366 appears well on the way to being the first of the project recipients to reach commercial application.

The company casts the wafers from molten silicon, cutting costs in half. The conventional method is to slice the wafers from a big block, turning half the silicon into dust. While Solyndra, the company that filed for bankruptcy, tried to sell a markedly different product, 1366 offers a commodity product made in a different way with lower production costs.

Jonathan M. Silver, the head of the Energy Department’s loan guarantee program, said, “It’s a process innovation, not a product innovation. They can produce silicon wafers with much less material and many fewer steps.”