This is what their site states:

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"Energy efficiency of the plant can be calculated in several ways. The energy efficiency that is probably of most interest is the energy in the combustible products that leave the plant divided by the total energy input. The energy input includes the energy in the dry feed, the electric power, and any natural gas that must be utilized to process the material. Energy efficiency for our current design is approximately 85%."

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So if the energy in the combustible products that leave the plant divided by the total energy input (dry feed, electric power, natural gas) comes out to 0.85, then, well, they get less energy out than they put in. But it is very efficient! They convert a wide variety of merely combustable organic wastes into a useable liquid fuel.

The same problem nagged bioethanol producers: out of the biomass feedstock they got alot of cellulose and hemicellulose, which easily ferments into ethanol. But they had a leftover waste called "lignin", which was combustable but not fermentable, and as a solid it wasn't very useful. The only way to get a net energy gain (and by that I mean more energy out than in) was to burn the lignin as boiler fuel for the fermentation and distillation process. That was the only way to turn the combustable lignin into a useable fuel, by contributing its combustion energy to another process that produced liquid fuel.