I agree, Daniel Nocera's team have done some really cool research and you're right that renewable fuels in general would be too expensive. I would argue that the cost of fossil fuels are artificially low because their current cost doesn't account for the environmental damage they cause. If we had to pay their true cost, the difference might not be so great.

I like to dream and so our long term ambition is to try and make complex molcules like cannabinoids directly from CO2, but we're some ways off.