CO2 to Green Fuel
Extending the limits of human stupidity
Economics that defies engineering
Media has been abuzz for a while with claims of converting Co2 into green fuels. SAF or standard aviation fuel from CO2 is one global attempt. And now Indians too have thrown in their hat in the ring, led by the almost revered ICT University of Mumbai with a claim to convert Co2 into DME (dehydrated methanol to be used as a LPG substitute)
The science behind the claim is well known and well proven. Here is the research paper:
DME derived from coal has been used as cooking fuel before. Largely in China. It is made from coal. And that makes good economic sense. And seems to be well established chemical engineering based on coal gasification.
But when you start to make it from CO2 then it gets into the realm of engineered economics – a new term I learned recently as an acronym for “scam”. Let’s get into mathematics and stoichiometry of DME from CO2 pulled from the air.
For a minute stick to DME. It doesn’t make sense to replace lpg with anything that has a oxygen molecule in it. At least not for a gaseous application. So ethanol or methanol is good for petrol blending, not for lpg replacement. By dehydrating methanol one gets DME. You replace LPG which is a mix of propane and butane with a lower hydrocarbon and that is methane. This is your best option. And you replace cylinders with piped gas. CNG or methane can be made from fermenting biomass or sewage or kitchen waste. It is called biogas or gobar gas and is a proven technology.
But that is not the point. Let’s look at the stupidity of converting CO2 when you have coal available in abundance. The energy produced in converting carbon to CO2 is less than the energy required to crack CO2. If that were not the case, it would be an above unity machine. Nothing is 100% round trip efficient, not even super capacitors.
If you have a leaky tap, you fix the leak. You don’t look for a better or faster mop. So the answer is not in converting CO2 into useful chemicals but in burning fuels such that you don’t generate CO2. If you want DME as an indigenous substitute for the more valuable LPG then you make DME from coal. Coal is converted to methanol and that is dehydrated to give DME.
I am sure ICT has done some good research. And hopefully something may come out of shooting darts in the sky. But converting CO2 into anything which can be made cheaper and greener directly from coal doesn’t make any sense.
But then, this is the day of engineered economics. Given the right amount of subsidy, anything can become viable.
Anything greener better be cheaper.
Else it is not worth doing.
We have a lot of failed experiments. Why go ahead with one more. Research done, paper published, thank you. But don’t start believing that this should be implemented.