Here's a quick overview of the case for synthetic 'ElectroFuels' for aviation by @ChrisGoodall2 in the @Independent.

It's crucial to note that this is entirely different from what the industry means when it talks excitedly about 'Sustainable Aviation Fuels', or SAFs.

SAFs are highly problematic, because just like other #Biofuels, they rely on a ready supply of Bio-based materials to use as 'feedstock' & each type brings with it a variety of #energy, environmental & #biodiversity complications.

For instance, SAF feedstocks include material with high Cellulose & Lignin content, such as wood or straw.
In addition, animal fats, vegetable oils, or sugars can be used.

These feedstocks can be by-products of timber or #food production, which sounds great, however they're not just lying around waiting for #aviation to buy up, convert to fuel & burn; endless industries, processes & businesses already make use of them.

Side note:
The conversion of these feedstocks into aviation fuel, is not without its own carbon emissions & the Government's advisor, @theCCCuk, recommends that all #biofuel production should be equipped with carbon capture & storage ( #CCS).

The gigantic scale of SAF production needed to make a dent in aviation's #Carbon emissions, would therefore displace existing uses for all sorts of feedstocks & require them to source something else instead - that doesn't cut #emissions, it just shifts them elsewhere.

This leads to another, well-known issue with large-scale Biofuel production: competition with the food system.

It's both simpler & cheaper not to bother with by-products & instead grow crops specifically for conversion to Biofuels.

We're familiar with one already: #PalmOil

Sadly, agriculture already has a huge impact on the #environment, climate & #biodiversity, so adding the burden of growing crops for aviation fuel to the mix, has some obvious & very serious undesirable consequences, not to mention huge Greenhouse Gas #emissions.

One more proposal for making sustainable aviation fuels, is using household #waste as feedstock.

This consists of:
1. Extracting the organic, or #food waste for processing, similarly to other biomass.

2. More ambitious plans, to convert unrecyclable #plastic waste.


...if turning the ubiquitous problem of #plastic waste, into liquid fuel for aeroplanes sounds a little too good to be true, I'm afraid it is and it's not hard to see why....

Plastic waste is a huge issue, for all sorts of reasons, but it does represent a store of fossil hydrocarbons in a solid, stable form.

Converting #plastic into transport fuel however, means that whenever it's used, that stored carbon is released into the atmosphere.

So, in #carbon terms, jet fuel made from plastic is similar to burning the oil/gas it took to make the plastic in the first place (plus the emissions from multiple production steps).

In exchange, we get a few minutes use, of an often superfluous material.

Sustainable? No.

Thoughts on the article:

As pointed out, sourcing sufficient #Co2 is challenging.

Drax power station in Yorkshire has been burning imported wood pellets in four of its six furnaces (converted from #coal) for years & is committed to figuring out how to capture its Co2.

As & when it's capturing carbon, Drax will be representative of a 'negative emissions' technology, the like of which IPCC climate stabilisation pathways are heavily dependent on: Bio Energy with Carbon Capture & Storage ( #BECCS).

BECCS understandably has its critics & I'm far from enthusiastic about relying on such a contentious technology to reach our climate goals, however it looks like we're stuck with it, so worth considering as a source of Co2 for electrofuels, at least in the medium term.

Another medium-term technology we're stuck with, is the fleet of combined cycle gas turbines, currently producing ~ 38% of the UK's electricity.

Gas combustion produces >40% less Co2 than coal for equivalent energy, but nevertheless, we should be capturing the Co2 emitted.

On the #Hydrogen side, the challenge is clear, although no less significant: securing massive amounts of renewable electricity.

My view, is that alongside legislating for escalating electro fuel content, the Government must require production to be vertically integrated.

That is to say, the energy majors & other aviation fuel partners, should not be allowed to cannibalise the electricity grid, to power Hydrogen via electrolysis.

This will spur competition, investment & innovation within the industry, of efficient Hydrogen production.

The advantage of this approach is threefold:
1. It separates aviation e-fuel production from the wider global energy market, removing exposure to price, supply & exchange rate volatility.

2. It removes the perverse influence of aviation demand for Bio feedstock.

3. Finally, it creates a reliable global market & supply chain for green #Hydrogen, which is generally expected to be needed well beyond 2050 in liquid form, to power long-haul flights, either via combustion, or fuel cells to power electric motors.

Of course, Hydrogen has long been a vital part of the world economy, but most of its production is dependent on natural gas & very #carbon intensive.

By harnessing the aviation sector to drive innovation & scale in green #Hydrogen, the benefits will cascade across sectors.

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