A Coal-based Fuel can Reduce CO2 in the Atmosphere

I crossed a Nature publication which explained how conversion of coal into liquid fuel could become the cleanest way to power jets, trucks and trains [1]. Wow, that was new for me! Putting the technology mentioned in the publication to an extremum, then using a car or fly around the world could be positive for the climate.

This is possible by creating a carbon negative fuel. Which means that in the whole fuel life-cycle, production and utilization, more carbon is stored in our earth than emitted to the atmosphere. The process for a carbon negative fuel is simple: Use less than 60% coal and more than 40% biomass and convert it into synthetic fuel while implement at least 80% carbon capture during the processing [1].

The processing method in more detail.

More than 90 years ago, two German chemical engineers developed a method to generate synthetic diesel from coal also known as Fischer-Tropsch process. The problem of a modern Fischer-Tropsch facility is that it produces large quantities of CO2 so that synthetic fuel would emit 50% more CO2 per barrel than traditional petroleum [1].

Although, the process is luckily suited for carbon capture and storage as the expensive separation of CO2 for a mixed gas stream is not necessary. The additional cost of compressing and storing the CO2 probably lies between $10 and $20 per ton [1]. Today, the price for EU Emission Allowances lies around $27 per ton CO2 which make the carbon capture option very attractive in Europe [2]. Adding the carbon capture method to the Fischer-Tropsch process would finally lead to a 5-12% better life-cycle footprint than a conventional barrel of petroleum [1].

Now comes the magic. The Fischer-Tropsch process can also handle biomass as a feedstock [1]. Biomass is carbon neutral. When it is combusted the emissions are roughly equivalent to the absorption of carbon, which let the plant grow. Therefore, when the biomass is used as feedstock in a Fischer-Tropsch process in combination with carbon capture, more CO2 can be buried in the soil than is later emit into the atmosphere as long as the biomass source is replanted which is definitely necessary for sustainable utilization.

Instead of a huge Desertec project in Sahara will there be a Forestec project in mid-Russia?

I like the idea, further studies should be made in this direction. Actually, I don′t know when such a design could become financially feasible. But what I know is that the economics of such a facility highly depends on the oil and emission price which both seem to increase over long-term. Further, the feasibility depends on the capital expenditures for the facility installation and the biomass price. The capital-intensive facility could take advantage through economy of large-scale factories and mass production, while the biomass price could be reduced through new harvest methods and new biomass infrastructure.

A final interesting thought can be concluded from that article. Oil can never run out in the next thousand years as long as we can produce it synthetical – just the oil production may be restricted by the amount of biomass we allow as feedstock.

[1] Schrag, D. (2009) ‘Coal as a low-carbon fuel?’, Nature Geoscience, 2 (12), pp. 818-820 [2] https://markets.businessinsider.com/commodities/co2-emissionsrechte [Accessed 03.01.19]