A Visit to the New Choren BTL Plant

I have written several essays describing biomass gasification. However, let’s review. Biomass gasification takes biomass – ideally some sort of waste (and I understand that the term “waste” can be contentious) plant material – and partially burns the material with a controlled amount of oxygen to produce carbon monoxide and hydrogen (synthesis gas, or syngas). One of the often overlooked benefits of the thermochemical approach over fermentation is that it can be used to produce chemicals, synthetic natural gas, or electricity – and from a wide range of feedstocks. There are many different variations of how the gasification process is done, and I will delve into the specifics of what Choren is doing in the next section.


Once you have produced syngas, you can go a number of different directions. You can burn the syngas to produce combined heat and power (this has some cleanliness and efficiency advantages over directly burning the biomass), produce methanol, ethanol (Range Fuels, Coskata, Syntec), mixed alcohols (Standard Alcohol, Power Ecalene Fuels), or hydrocarbons like diesel via the Fischer-Tropsch process (FT). This latter approach is what Choren is doing. The diesel they are producing is not biodiesel, but “green diesel” as I have described in this essay (scroll down to the “renewable diesel” section).

To my knowledge no other company in the world is as far along as Choren is in producing diesel (and maybe any liquid fuel) from gasifying biomass. Whereas Range Fuels is currently building a plant (and the schedule for that is already slipping), and Coskata is building a much smaller demonstration plant, Choren has been piloting their technology since 1998, and their new plant is mechanically complete. (Yet Choren – funded largely by private investors – has been pretty low-key, issuing a fraction of the press releases of some of the other biofuel companies).

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