What are biofuels all about

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TL;DR

Hot take

Biofuels such as sustainable aviation fuels promise a lot - a carbon-neutral equivalent to existing fossil based fuels that can be substituted without major changes to machinery or infrastructure.

They are only available in limited quantities and scaling them up to replace all fossil fuels will require massive amounts of land use.

Explanation

Sustainable aviation fuel is a type of bio-fuel that is made from organic compounds - left over food waste, cooking oils and other ingredients. It results in a fuel that is very chemically similar to the existing fossil based fuels burnt in combustion engines. This means it can be substituted without having to make major modifications to the engines, or the infrastructure that distributes it - e.g. the trucks, pipelines, storage tanks etc. In some cases it is blended in to dilute fossil fuels.

That’s the dream. But wait, if it’s chemically similar to existing fossil fuels doesn’t that mean it releases CO2 into the atmosphere when burnt? It does. However, the distinction here is these biofuels are meant to be made with forms of CO2 that are part of the natural carbon lifecycle, or “recent CO2”. This distinguishes them from the CO2 that results from digging up fossils that have been buried for hundreds of millions of years and leads to the clam of carbon neutrality.

So this is up there with growing trees to burn trees to make power. The trees when growing absorb CO2 from the atmosphere, and then burnt they release it. So it all evens out. This is very much what is happening when these fuels are made from organic matter - crops grown specifically for this purpose, or using by-products of crops.

The US consumes around 20 billion gallons of jet fuel a year, and is expected to hit 35 billion by 2050. The current capacity for used cooking oils, fats and greases is only 1.5 billion gallons annually. So there’s a massive shortfall. That’s also just looking at aviation - what about all the transportation and production of the these biofuels, how is that going to be powered?

The problem here is where did the ingredients come from. If you’re going to grow crops specifically for these fuels that requires a ridiculous amount of land. So now you’re using a lot of land to grow food but the food is going to make fuels to move big machines around. We’ve also seen examples with palm oil where forests are cut down to make way for farm land to grow palm oil - a terrible outcome. Like the Amazon being cleared to make way for grazing land for cattle - a carbon negative.

The choice here is - scale up a massive industry to create this substitute fuel so we can carry on as per normal, or look at alternatives such as reducing air travel, improving other forms of transport. The answer is a combination of all of those things in reality.

What are biofuels all about

TL;DR

Explanation

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