Biofuels vs E-fuels

I wrote about the conversation I had around biofuels and e-fuels that are produced through power-to-fuel approaches. They have rather different chemical pathways, costs and constraints. I’d really like to see someone consider the resource intensity of these different approaches. The challenge for most studies is that they consider biofuels from a standpoint of resource potential as though the agriculture activities are inert. Of course there’s the whole question of whether land should be used for cultivation of food or energy. I won’t get into that.

But I’d be curious to see if people who can organise the supply chain across the land, the supply of food alongside the supply of feedstock towards the bioenergy plants had done their analysis on resource intensity. A good comparison of the resource intensity from the water-intensity, output logistics standpoint would be really good. It doesn’t have to be a full-fledged lifecycle assessment – back of envelope calculation would be helpful.

There is a view that bioresources are limited by the amount of feedstocks available. There is only this much used cooking oils (UCO) that you can convert to hydrotreated vegetable oils (HVOs) or into biojet fuel (typically via the Hydrotreated Esters and Fatty Acids (HEFA) pathway). And that power-to-liquid is theoretically not limited in terms of resource potential. That is not exactly true because we are still limited in our green options for power generation and green power itself can eat into resources required by other sectors. The conversion process to fuel also requires carbon dioxide feedstock of suitable concentration as well as pure water to be electrolysed to produce hydrogen.

It’s strange to think that we can have unlimited power or that we can easily power the world – remember those times when people actually calculated the amount of solar panels and space on land that is needed to power all the earth? The investment to be made in terms of building lines to distribute power, and the factories to take that power and convert them into the fuel needed would multiply the complexity problem of supplying the world’s energy needs.