Seems like a “potential” good news story (though reducing food waste would surely be a better idea)

https://www.bbc.co.uk/news/science-environment-56408603

But..

The authors of the new study say the fuel cuts greenhouse gas emissions by 165% compared to fossil energy.

How can you cut something by 165%??

Reducing is better, yes, but there is inevitable wastage in food processing, brewing etc. Plus it uses manure as well (no details if that’s sewage or animal based). If this is a relatively “easy” process then this is an excellent advance as it means you don’t have to mess about with inefficient Fischer Tropsch processes and such.

How can you cut something by 165%??

I think it’s because they are sequestering methane (CH4) which is a far more potent greenhouse gas than CO2 so by doing so they are reducing the total resultant emissions far more than just using fossil fuel.

I’ve just read this story and was filled with an unfamiliar feeling – not really “hope” as such, more just the absence of abject despair.

Please don’t ruin it for me….. this feels like good news, right??

This is obviously a useful development if it involves a more efficient process, but you need to be realistic about how much potential feedstock there is versus the global demand for jet fuel and diesel. If you think about how much food you throw into the garbage and remember that only a fraction of that mass will end up as usable fuel, then think about how much fuel an average car uses in a week, it’s pretty obvious that converting every last scrap of food waste would only replace a small percentage of all fossil fuel. Still worth doing, but ultimately, we have to use cars, trucks, planes, etc. a lot less. The danger with this kind of thing is that rich countries mandate e-fuel targets and then you end up burning down rainforests in poor countries to grow crops to produce fuel because there isn’t enough feedstock.

From the paper

Wet waste is a low-cost, prevalent feedstock with the energy potential to displace over 20% of US jet fuel consumption; however, its complexity and high moisture typically relegates its use to methane production from anaerobic digestion. To overcome this, methanogenesis can be arrested during fermentation to instead produce C2 to C8 volatile fatty acids (VFA) for catalytic upgrading to SAF.

Looks good, widely available waste as input, will still need energy inputs for the refining stage.

If you think about how much food you throw into the garbage and remember that only a fraction of that mass will end up as usable fuel, then think about how much fuel an average car uses in a week,

It reminds me of a similar story a few years back about making biofuels from waste coffee grounds. The story carried a figure for a global  total  for the volume of coffee ground it speculated could be harnessed and it made everyone excited. I only put 25 – 50 grams of coffee waste in the bin each day. As much as 10% of that weight could be exploited as a useable fuel! (having dissolved it in solvents and cooked it for two hours) to provide me with, approximately, one teaspoon of diesel. Perfect for my daily round trip commute of 70 meters.

Nothing new – the old landfill in Rossendale (Horncliffe woods) has a small 1mw methane powered internal combustion generator power station that’s been running for ~20years rotting waste.

They capped the landfill and a network of pipes taps the methane off and directs it to the containerised generator set. It will still produce Co2 but be less harmful than the methane.

The new thing is stopping the fermentation at long carbon chains rather than letting it run to methane. Methane can be reformed into jet fuel (e.g. Shell) but that requires more energy.

Exactly.

Of course the environmental experts will be along soon to tell us that it’s an inefficient process and we should just forget about it and plough everything into battery tech.

It reminds me of a similar story a few years back about making biofuels from waste coffee grounds. The story carried a figure for a global total for the volume of coffee ground it speculated could be harnessed and it made everyone excited. I only put 25 – 50 grams of coffee waste in the bin each day. As much as 10% of that weight could be exploited as a useable fuel! (having dissolved it in solvents and cooked it for two hours) to provide me with, approximately, one teaspoon of diesel. Perfect for my daily round trip commute of 70 meters.

You do realise that is actually a decent quantity? How much oil do you think is produced per tonne of rapeseed for example?

If you think about how much food you throw into the garbage and remember that only a fraction of that mass will end up as usable fuel,

It would probably be better for the environment to stop wasting so much food and by implication growing/producing way more than we need.

Another major advantage is that this new fuel produces around 34% less soot than current standards. This is important because soot plays a key role in the formation of contrails from airplanes

Will they have to change how they put the mind control chemicals?

Aircraft already use fuel blended with biofuel, upto about 35% I think so this is just another wing of biofuel. I think the challenge would be to get sufficient supplies of waste food and process enough of it to make a difference especially in the backdrop of people becoming aware of their food waste and probably trying to reduce it – I know we are and throw away significantly less food waste than we used to. No reason why some volume of it could be made and introduced into the aircraft fuel supply chain, but it would be a tiny percentage. Far better off to make it available for road transportation as that emits many orders of magnitude more CO2 than aircraft and far easier to introduce into the ground transport fuel supply chain than aviation I would have thought.

It would probably be better for the environment to stop wasting so much food and by implication growing/producing way more than we need.

It would probably be better for the environment to stop wasting so much food and by implication growing/producing way more than we need.

See my earlier point that not all food waste streams (in fact very little in all likelihood) are domestic in origin. Most of it comes from commercial/industrial processing byproducts – straw, husks, brewery leftovers, abbotoir waste etc.

A friend worked in a spinoff from Canterbury University doing advanced fermentation things. The only thing they gave up on was trying to get a good process to ferment abattoir waste.

I think it’s because they are sequestering methane (CH4) which is a far more potent greenhouse gas than CO2 so by doing so they are reducing the total resultant emissions far more than just using fossil fuel.

I agree that’s how they are making the claim. It would be more useful if they compared the new technology against the existing, ie, capturing landfill methane and burning it to generate electricity, rather than inflating the benefit by assuming all the methane is currently released. Scientific advances are great but they need to be honest not spun.

Of course the environmental experts will be along soon to tell us that it’s an inefficient process and we should just forget about it and plough everything into battery tech.

This environmental expert thinks that a far better use for food waste is to produce methane for use in the gas grid. Run it through a condensing boiler and you’ll extract up to 90% of the energy from the fuel. Obviously, noting the point about wasting less in the first place.

I agree that’s how they are making the claim. It would be more useful if they compared the new technology against the existing, ie, capturing landfill methane and burning it to generate electricity, rather than inflating the benefit by assuming all the methane is currently released. Scientific advances are great but they need to be honest not spun.

I’m reminded a bit of a view that the only reason the gas networks are keen to either switch to or blend in more hydrogen is for naked self-interest. Turkeys would never vote for Xmas after all!

I’m reminded a bit of a view that the only reason the gas networks are keen to either switch to or blend in more hydrogen is for naked self-interest. Turkeys would never vote for Xmas after all!

It’s that or be left with several billion quid’s worth of stranded assets.

Landfill gas capture isn’t 100% so tehre will be some shortfall but I agree it’s a claim that isn’t all it appears to be. I need to read the paper to be sure though.

A friend worked in a spinoff from Canterbury University doing advanced fermentation things. The only thing they gave up on was trying to get a good process to ferment abattoir waste.

They should have stuck in at school 😉

https://pubmed.ncbi.nlm.nih.gov/27575339/

This environmental expert thinks that a far better use for food waste is to produce methane for use in the gas grid. Run it through a condensing boiler and you’ll extract up to 90% of the energy from the fuel.

It neednt be an either/or scenario but air travel isn’t going to go away as much as people would like to pretend otherwise. If we could lower the environmental impact of that then thats a far bigger target. Domestic heating can be run from electricity or other renewable sources, planes not so much (right now).

It neednt be an either/or scenario but air travel isn’t going to go away as much as people would like to pretend otherwise.

It is actually: there simply isn’t the volume of feedstock to do both. So you’re left with competing solutions for using the waste, one of which is far more efficient (and essential) than the other.

Domestic food waste collection is standard in my area any way so the amount of food waste available is huge. I didn’t realise that wasn’t standard across the UK. The question is then what is the best use for the fuel produced

But even if a plane was solar powered vapour trails contribute as much to global warming as the planes CO2 emissions

I wonder if the only way we can still fly is to carbon capture. That would seem to be a reasonable cost to pass onto people that fly

I think it’s because they are sequestering methane (CH4) which is a far more potent greenhouse gas than CO2 so by doing so they are reducing the total resultant emissions far more than just using fossil fuel.

I agree that’s how they are making the claim. It would be more useful if they compared the new technology against the existing, ie, capturing landfill methane and burning it to generate electricity, rather than inflating the benefit by assuming all the methane is currently released. Scientific advances are great but they need to be honest not spun.

The 165% is largely down to Methane capture. the rules in place mean that when you capture methane that would otherwise go to atmosphere, the equivalent GHG saving over say using paper waste/woodchip/rubber/plastic is greater. The values for GHG savings are based on the REDII directive which sets the GHG Savings based on a Fossil Fuel Comparator @ 94gCO2/MJ. If your process removes this amount it becomes carbon neutral, if you go beyond this figure its carbon negative.
The general feeling is that the only way to go negative is to harness methane emissions, though there is an argument to say you can do this for other waste products, but the processing technologies utilise too much non-renewable energy at this to get 100%+ savings, though we are all hopeful this is likely to change eventually. You also need to prove that your process is removing these emissions in a fashion in excess of existing technologies – lan example would be incineration of municipal waste, this produces power so is therefore giving you some GHG savings, there will be other pollutants from incineration so it is better to utilise that waste in a more efficient manner.
GHG savings is a very complicated web of understanding processes and life cycle of carbon (part of the issue with EV), but there are a number of companies working very hard to prove that the technologies they are optimising (most are actually very old) are a very real viable solution to replacing fossil liquids.

However, I would say that the products produced out of these processes are far better directed at road/transport and not air use, where there are not so many restrictions on how it’s made, looks like and behaves.

ref soot. This is true and a good example is your “Aspen” fuel, an alkylate fuel. The reason this is used in forestry is that it has very good “local emissions”, this is because there is next to zero aromatics in the fuel.

Soot comes from heavier Aromatics in the C8-C10+ range in gasoline, so it buns clean without much coking in the engine.

The same can also be said for Kerosene and diesel cuts. By utilising these technologies, you are producing paraffinic streams, with very low aromatics in them that burn cleanly. So whilst they are very good at reducing GHG holistically, they also have a local benefit, to the point where large diesel engines in trucks can in theory be “air purifies**”
**this is based on other infrastructure such as restaurants, gen sets contributing to local emissions..

edited for clarity.

the amount of food waste available is huge.

Well, a ballpark figure for U.K. fuel use is 700 litres per year per person. That’s only petrol and diesel, not coal, etc.

https://www.racfoundation.org/data/volume-petrol-diesel-consumed-uk-over-time-by-year

That’s in the ballpark of 10 kg per person per week. Most food is largely composed of water, so the usable fuel you will get after processing will be a small fraction of the input. Just for argument’s sake, say it’s 10% the mass, then you would need 100 kg of food waste per person per week to replace petrol and diesel. It’s pretty obvious that households aren’t putting hundreds of kgs of food into the rubbish each week. Large cities might be producing thousands of tonnes of waste, but that’s still just a tiny fraction of what would be needed to replace diesel and petrol fuels. Of course it’s worth doing if it helps at all, but the brute reality is that we need to dramatically slash the use of cars, air travel, etc.

Edit. Here’s a table of alcohol per ton of different foods. Potatoes give 1 gallon per 100 pounds, so less than 10% by mass. Most food waste will probably be of much worse quality than potatoes, so the average household is not going to cover their fuel usage by converting food waste into fuel.

http://journeytoforever.org/biofuel_library/ethanol_motherearth/z/1Table2.gif

Can’t we just go back to the age of sail and have longer statutory holidays or something in our new work from home world?

Then those of us that really like to travel, don’t have to deal with drunk holidaying cretins.

Everyone in Cardiff (and Wales apparently) puts their food waste in their brown bin every week. Assuming this is done by commercial premises too. According to the internet it’s anaerobically digested into biogas for heat and power, and solid fertiliser for farms.

That suggests it’s all being used already. How much waste in the food chain is actually being wasted? If we made it into jet fuel would we end up having to use the melted dinosaurs for these other purposes?

Can’t we just go back to the age of sail and have longer statutory holidays or something in our new work from home world?

No need for longer hols, just work from the boat.

Here’s a table of alcohol per ton of different foods. Potatoes give 1 gallon per 100 pounds, so less than 10% by mass. Most food waste will probably be of much worse quality than potatoes, so the average household is not going to cover their fuel usage by converting food waste into fuel.

That’ll all change when ethanol from cellulose becomes viable.

That’ll all change when ethanol from cellulose becomes viabl

fermentaion from cellulosic compounds is widely used, a lotof it happens in scandic regions. it doesn’t all end up as alcohol though, a lot goes to producing naphtha.

I’ve just read this story and was filled with an unfamiliar feeling – not really “hope” as such, more just the absence of abject despair.

Please don’t ruin it for me….. this feels like good news, right??

Feels more like a bit of greenwashing by the aviation industry?

By that I mean once you have a hydrocarbon chain you can pretty much do anything with it.

Heat your house, drive your car, make plastics, sequest it underground.

But if you tell people it’s powering planes then you can throw your potato peelings in the food waste and book that 10 day eco- friendly mud hut break in Thailand without any guilt about the CO2 released on your 12h e/way flight.

That’ll all change when ethanol from cellulose becomes viable.

This stuff isn’t magic. You have carbon atoms bound into organic compounds. They can be converted into a different compound that is more useful as a fuel, but there are physical constraints on how much energy you can recover. You can make fuel from lawn clippings, but you would need a vast amount of biomass to replace all the petrol, diesel, and jet fuel we use.

I ‘avgas after my Friday curry if anyone wants to buy some.

This stuff isn’t magic. You have carbon atoms bound into organic compounds. They can be converted into a different compound that is more useful as a fuel, but there are physical constraints on how much energy you can recover. You can make fuel from lawn clippings, but you would need a vast amount of biomass to replace all the petrol, diesel, and jet fuel we use.

There’s also more than one way to convert waste into energy.

Ethanol is just seen as useful as it’s relatively easy to process into other chemicals or just put it in the tank of a petrol-engined car (with a few mods).

For example, https://www.circularonline.co.uk/news/air-products-scrap-teeside-efw-development is one I worked on, although at £770million for a white elephant that doesn’t work I should probably keep that one quiet!

That plant took just about any combustible waste, used plasma to gasify it at incredibly high temperatures (this was the problem there isn’t a refractory lining available that can deal with them), treats the syngas produced and burns it to make electricity.

Or linking back to my previous point, you could write that as “waste to power 100,000 homes”, or “waste to power 100,000 electric cars”, or “waste to power electric trains”, or “waste provides feedstock to chemicals plant”. The technology is often fairly independent of the end use.

It is actually: there simply isn’t the volume of feedstock to do both. So you’re left with competing solutions for using the waste, one of which is far more efficient (and essential) than the other.

Then air wins.

Domestic heating can be run from electricity or other renewable sources, planes not so much (right now).

.

But even if a plane was solar powered vapour trails contribute as much to global warming as the planes CO2 emissions

LOLWUT? Where do you think the vapour comes from? It’s certainly not the passengers.

That suggests it’s all being used already. How much waste in the food chain is actually being wasted?

Probably more than you realise, a lot of AD feedstock is rejected because of contamination, not because it’s unsuitable but because it has pizza boxes, dog eggs etc. that the site isn’t licensed for.

Thanks @sui and @thisisnotaspoon.

This stuff isn’t magic. You have carbon atoms bound into organic compounds. They can be converted into a different compound that is more useful as a fuel, but there are physical constraints on how much energy you can recover.

Funnily enough, I am aware that it’s not magic.

The point is there is far more cellulose available and it can be grown far easier than starch.

Then air wins.

If you want to waste over 60% of the energy content in the fuel, then sure.