this post was submitted on 29 Dec 2023
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UK firm develops jet fuel made from human poo | The starting material is generated in excess and available in plenty. It is a win-win for everyone that the waste is repurposed.::undefined

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[–] arandomthought@sh.itjust.works 46 points 11 months ago (4 children)

Is this another one of these "eco-fuels" that take about ten times the energy they store just to produce them, and no one will tell you where that energy will come from?

[–] Wrench@lemmy.world 14 points 10 months ago

Well, I've always wondered what would happen after humanity burns through all fossil fuels on the planet, if flight and space flight would be impossible. So at least it seems like it's possible with renewable resources.

It's comforting that future generations will still be able to reach for the stars in doo doo rockets.

[–] 1rre@discuss.tchncs.de 14 points 10 months ago (2 children)

I mean if you can get it from actually good sources (solar, geothermal) where that type of energy is in excess then use ships powered by it to transfer it around the world is that a huge problem?

[–] Sasha@lemmy.blahaj.zone 2 points 10 months ago

It might be, if it's more efficient to use that energy for some other option.

[–] 4am@lemm.ee 1 points 10 months ago

No, see if it’s not the perfect solution to literally everything then it’s just not gonna work. /s

[–] rob_t_firefly@lemmy.world 12 points 10 months ago (1 children)

Together, the research team developed a process to convert human waste into a thick, black liquid that looks like crude oil and behaves like it. Using fractional distillation, the team can then derive the fuel of interest, much like oil refineries do.

Based on the (almost no) data available here, this does seem likely to be a lot of steps and a lot of energy required just to turn the poop into the substitute for crude oil, and then do all the standard further refining of that into jet fuel. I'd be very dubious about the actual real-world value until some magical further data is shared, because this innovation surely won't help anyone if the fuel it makes is more expensive than regular jet fuel.

[–] GreyEyedGhost@lemmy.ca 11 points 10 months ago* (last edited 10 months ago) (2 children)

I'd be completely unsurprised to learn they were using thermal depolymerization. The process was patented about 30 years ago and can take just about any organic material and turn it into essentially light oil. When there was a plant testing it with turkey carcasses in the US, way back in 2003, it was competitive with oil production costs, provided that turkey guts cost less than $20/ton and oil cost more than $80/barrel.

I have been saying we should use this for waste treatment plants since they first started testing this. The water we get at the end is more pure; drugs, most chemicals, and germs are broken down; and we get a saleable product at the end. Depending on the cost to build and run, we could get a better result for less money.

Now, let's talk about the efficacy of converting human remains and the price of cemetery plots...

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[–] Meowoem@sh.itjust.works 6 points 10 months ago

The energy comes from excess generation in renewables for load balancing, that base load thing people mistakenly say they can't do.

It's clever and simple, you put a whole load of potential generation in knowing that to meet your essential and desired demand on low generation days you'll need excess capacity which will over produce on high generation days. You then plug that in to a system which has tanks of feedstock in this case poo and empty storage capacity so that in peek generation periods it can run at maximum, when it's only a little over the requested load it runs at limited power and if there's a time with no excess power it turns off for a bit.

That's why all the carbon capture and processing facilities are focusing on modular parallel design, it's very easy then to create scalable production tied to excess load.

Of course this is only one of the many possibilities, the nuclear lovers want to build nuclear powered sequestration and processing facilities, Iceland made one using geothermal, the American one is wind and the proposed Saudi one trailer about being solar thermal.

Oh and actually the efficiency is incredibly impressive now, with some of the active catalyst chemistry they're developing we're getting into heat pump style efficiency gains and it'll looking more likely we'll be able to go below parity in cost per gallon Vs mined hydrocarbons.

I know it feels like people never explain the complex side of things but that's because journalists are bad at their jobs, there's whole organisations out there dedicated to this sort of planning and a lot of the stuff they talk about and work towards ia incredibly well thought out and sensible.

[–] robotopera@sh.itjust.works 42 points 11 months ago (1 children)

Do you smell that Randy? It's chemtrails and they're brewing up a shit storm right over our heads.

[–] Treczoks@lemmy.world 24 points 11 months ago (6 children)

Another stupid fuel idea. How many #2s do you need to fly from New York to Los Angeles? Probably a shitload...

But seriously, this is just another idiotic Idea. Yes, you can make fuel from a lot of sources, but neither the quantity is there, nor is this in any way efficient or cost-covering.

I once calculated that we would need to cover each and every square centimeter of agricultural area in my country with rapeseed plants without crop rotation to produce the bio-fuel that the jets in my country burn. And that does not even include the energy needed to plant it, harvest it, and process it.

[–] Tangent5280@lemmy.world 5 points 10 months ago (1 children)

Fun thing about calculations is that if you write them down you can pull them out and show it to people who are skeptic about your claims, like I am being right now of your claims.

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[–] Meowoem@sh.itjust.works 3 points 10 months ago (1 children)

Your claimed calculation is very vague, I have to say I don't believe for a second you actually did that and it's laughable you're claiming you did

When someone tells me that they've noticed a fundamental flaw that all the leading minds in the field have not it does not lead me to think that the field itself is flawed rather the person I'm speaking to's understanding of it.

Of course we understand that it's not all going to come from one source but where there are waste products like stalks and leaves left over from food production, poo, algae, and etc it makes sense to work towards using all of those so we can transition away from the extracting oil and gas.

[–] Treczoks@lemmy.world 3 points 10 months ago (4 children)

It is not that I had found a "fundamental flaw". Those eco-fuel things simply don't scale up to realistic levels, and the people who are behind it know that their small-scale experimental systems will never power the current level of aviation fuel demands.

Yes, human poo has some energy left. But it is way less than the same amount of fuel, I.e. you need several tons of poo to create a ton of fuel.

OK, lets have a look at this poo idea. Human faeces have an energy density of 8kJ/g. Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1793018/#:~:text=As%20the%20energy%20content%20per,measurements%20of%20stool%20wet%20weight.

Aviation fuel has an energy density of 43.5kJ/g. Source: https://s2.smu.edu/propulsion/Pages/energyex.htm#:~:text=The%20energy%20density%20of%20aviation,about%20820%20kg%2Fm3.

So if it was possible to get a lossless conversion of human poo to aviation fuel, you would need more than five tons of poo to create one ton of fuel.

A 747 from NY to LA burns about 60 tons of fuel. Source: https://www.quora.com/How-much-fuel-is-needed-to-fly-a-Boeing-747-from-New-York-City-to-Los-Angeles#:~:text=New%20York%20to%20LA%20would,be%2016%2C716%20gallons%20of%20fuel.

So you would need over 300 tons of shit to power that flight - if the conversion was lossless. It most likely is way worse.

Now a human produces between 125 and 500g of faeces per day. Source: https://www.healthline.com/health/do-you-lose-weight-when-you-poop#how-much-does-it-weigh

So you would have to collect the days worth of shit of way over half a million people to power this flight. And all this - again - with a lossless conversion. The reality is probably more like a 10% conversion productivity, meaning you would need ten times the poo.

I leave the question if this technology is actually sustainable to the reader.

And yes, my calculation of rapeseed oil based fuel was similarly funded in facts.

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[–] Corkyskog@sh.itjust.works 3 points 11 months ago

That's a lot of Canola oil!

[–] pineapplelover@lemm.ee 2 points 11 months ago (1 children)

I mean I'm pretty sure a water treatment center can spare some shit for this test

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[–] cosmicrookie@lemmy.world 20 points 10 months ago (2 children)

You get a 10% discount if you use the lavatory during the flight

[–] A_Random_Idiot@lemmy.world 3 points 10 months ago (2 children)

if I eat the fiber heavy in flight meal, will that be knocked up to 15%?

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[–] chitak166@lemmy.world 12 points 10 months ago (1 children)

I've always thought about how cool it would be to find a use for cat shit.

Imagine if every time your cats used the litter box, it made you money.

[–] cosmicrookie@lemmy.world 4 points 10 months ago (3 children)

Have you tried grinding it into a powder and mixing it with your coffee?

[–] chitak166@lemmy.world 6 points 10 months ago (1 children)
[–] ChaoticEntropy@feddit.uk 14 points 10 months ago (1 children)

You drink your cat shit straight, like god intended.

[–] WeirdGoesPro@lemmy.dbzer0.com 4 points 10 months ago

That’s why they call me Mr. Mistopoolees.

[–] Akasazh@feddit.nl 2 points 10 months ago

A civet cat isn't a true cat, it got the name because it remotely looks like s vast

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[–] Meowoem@sh.itjust.works 11 points 10 months ago

This is a fantastic idea, here in the UK we've just been dumping raw sewage in the rivers and poisoning the coast because it'd cut into water companies record profits to treat it (also Brexit chemical shortages or something)- if we can turn the poop into something useful that can sell then the won't let a drop off that precious filth go to waste.

[–] verdantbanana@lemmy.world 10 points 10 months ago

well shit

shitter will never be full again

[–] deafboy@lemmy.world 4 points 10 months ago

Na kilo hoven, kilo cukru...

[–] iquanyin@lemmy.world 4 points 10 months ago (3 children)

let poo return to the earth. jets also. we don’t need poo jets adding to the crap in the air.

[–] Meowoem@sh.itjust.works 4 points 10 months ago (4 children)

You're not going to stop people living their lives, visiting friends, family, and having meaningful life experiences. If we can make flying more ecologically sustainable than rail and boats then it would be a hugely positive thing in the fight against climate change.

[–] chitak166@lemmy.world 5 points 10 months ago

We can stop them by taking their money away and giving it to those who need it.

No leisurely intercontinental flights until all children are free from starvation!

[–] Sunfoil@lemmy.world 2 points 10 months ago (3 children)

To be even more doomer, people will have to stop living their lives when we run out of everything, so we might as well start winding down now.

[–] cosmicrookie@lemmy.world 3 points 10 months ago* (last edited 10 months ago)

I'd argue that private jets would have to be banned before I'd accept any regulation on economy flights to visit my family that I see every two years

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[–] FluffyPotato@lemmy.world 2 points 10 months ago

Stop subsidising air travel and people are gonna prefer trains and boats real fast.

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[–] A_Random_Idiot@lemmy.world 3 points 10 months ago

As if flying wasnt a shitty enough experience as is.

[–] ratzki@discuss.tchncs.de 3 points 10 months ago

The environment would be saved if I could turn all the shit I experience at work into fuel.

[–] londos@lemmy.world 3 points 10 months ago

Fast as shit.

[–] FrankTheHealer@lemmy.world 2 points 10 months ago (2 children)

Will it still pollute the atmosphere?

[–] ForgotAboutDre@lemmy.world 8 points 10 months ago (1 children)

Yes. But the waste is likely to still produce methane that has a bigger climate warming effect that the equivalent co2 of burned but for a shorter period. The general consensus suggests it's better to burn methane than release it into the environment.

The better solution is to fly less, or wait till flying truly green. The big issue is the incredible amount of subsidy we allow for airlines. Tax or fuel for aircraft is very low. If we cut these subsidies and starting taxing aircraft fuel at similar rates to cars electric/hydrogen aircraft would come about much sooner.

[–] Numberone@startrek.website 2 points 10 months ago (1 children)

Also, if its in human poo it's already in the carbon cycle and so really less of an issue. The problem is bringing up carbon that's been removed from the cycle (subterranean oil or gas pockets) and putting that back into circulation. Granted it would be better to pull carbon out of the atmosphere (somehow), but at least using poo wouldn't be adding NEW carbon. That's my understanding anyway.

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[–] mtchristo@lemm.ee 2 points 10 months ago

It's raining shit. Hallelujah!

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