SRI estimates that its zero-carbon process will generate jet fuel for $2.82 per gallon, which is under DARPA’s $3 target. SRI’s projected capital cost for a 100,000 barrel/day plant—$3.2 billion—is well below the $6 billion cost of a CTL plant, but still well above DARPA’s $1.5 billion target.

Park says SRI needs to prove its process beyond its “bench-scale” demonstrations in order to provide such cost estimates with any degree of certainty. Based on experience with his own oxygen-less gasification scheme—which is being developed for waste-to-energy plants by Riverside-based spinoff Viresco Energy—Park is skeptical that electrical heating will prove feasible at larger scale.                      

Eric Larson, a research engineer with Princeton University’s Energy Systems Analysis Group, says SRI’s zero-carbon process could prove to be “technically doable” and still suffer from a critical flaw: producing a carbon-based fuel that will release carbon dioxide when it is burned. “On a life-cycle basis, the fuel is no better than petroleum fuel on greenhouse-gas emissions,” says Larson.