Air-Blown for CHP, Oxy-Steam for Fuels: One Machine, Two Pathways

Jenja is the same piece of hardware whether it runs air or oxygen. The difference is what comes out the other end.

Air mode

Feed air as the gasification agent. About 45 to 50 percent of the syngas volume becomes nitrogen. That dilutes the energy: heating value lands at 4.5 to 6.5 MJ/Nm3, hydrogen sits around 15 to 18 percent, H2/CO around 0.8 to 1.0. The gas is perfect for a spark-ignition engine. This is the CHP configuration: 60 to 85 kWe net plus 250 kWth of heat, plus up to 144 kW of cooling with an absorption chiller. This is what the COMETHA campaign ran in Paris for 1,939 hours. Simple, no oxygen plant, no steam supply. The machine makes power, heat, and cooling from waste.

Oxy-steam mode

Swap air for pure oxygen plus steam. The nitrogen disappears. Heating value jumps to 12 to 15 MJ/Nm3, hydrogen to 33 percent, H2/CO to 1.95. The gas is now a chemical feedstock, not just a fuel. That composition lands inside the window a cobalt Fischer-Tropsch catalyst needs, which means it can feed a reactor making sustainable aviation fuel, or a methanol synthesis loop, or a hydrogen separation unit. No water-gas shift stage required upstream. The gas is already FT-ready after sulfur and tar polishing.

Why it matters

The bet is simple. A site deploys Jenja today in air mode for power, heat, and cooling, using its own waste as fuel. In three years, when the site is ready to move into fuel production or the regulatory economics shift, it switches the gasification agent to oxygen-steam. The gasifier itself is unchanged. The switch needs an oxygen supply, a PSA or cryogenic unit at roughly EUR 30,000 to 50,000, and steam integration. That is the entire retrofit.

No competitor's machine can do both. Volter, Spanner Re, Burkhardt, and Syncraft all run air-blown only. None offers oxy-steam syngas. None can feed an FT reactor. Jenja is the last gasifier a site ever needs: power today, fuels tomorrow, same container.

Likely objections

Someone will say switchable oxy-steam in a single small downdraft unit does not exist commercially. Correct. That is the point. And to be honest about the state of the data: the FT-ready claim rests on the 1,939-hour COMETHA gas-composition dataset, but COMETHA ran air-blown, and no tar measurement in oxy-steam mode has ever been published on any downdraft machine. That first dataset is still ahead. The hardware is validated. The final fuel-synthesis chain is the remaining engineering, not a proven commercial product yet.