Is there any hope for a green aviation industry?

After being "stonewalled" by his bosses over concerns about decarbonisation claims, Finlay Asher quit his job as a senior aviation engineer at Rolls Royce to found Safe Landing, an organisation that campaigns against growing the aviation sector.

Alasdair spoke to him about this journey, the reasons technological and market-based solutions to aviation emissions are not going to get us to net-zero, and what the sector should be doing instead.

Further reading: 

• Check out Finlay's Youtube channel
• Stay Grounded’s greenwashing fact sheet series
• T&E’s EU Aviation 2050 roadmap
• ICCT’s ‘Aligning Aviation with the Paris Agreement'

Click here to read our investigation into the UK biomass supply chain, or watch a clip from the BBC Newsnight documentary.

Transcript

Alasdair: 0:06

Hello, and welcome back to the Economy, Land and Climate Podcast after a short summer break. My name is Alasdair MacEwen and in this episode we're aiming to dip into the aviation sector by talking to Finlay Asher, a mechanical engineer with a background in the aviation industry, and now an active voice on how the sector should look to reduce its greenhouse gas emissions.

Finlay: 0:26

To me, this is like the absolute prime masterclass of greenwash. And my reading of this situation is it was masterminded by Shell as well, because it's them that push this phrase most consistently from an early stage. But it's really clever because if you say'sustainable aviation fuel', then someone's like, okay, it's sustainable.

Alasdair: 0:44

I started by asking Finlay how he got into working on the subject of aviation and climate.

Finlay: 0:50

of our generation. What can I do to do with that?' I thought, 'I'll do something practical and tangible. If I do mechanical engineering, I can design wind turbines, or wave power, or whatever.' And I think partly, my dad was a civil engineer as well. So I was a bIt kind of minded to do engineering, but not the exact same type as him. I mean, I did actually work a place called Artemis Intelligent Power just north of Edinburgh near Liberton. And they did hydraulic gearboxes for wind turbines. So I did a kind of placement there. But then, when I needed to do a six month placement as part of my degree, I applied to loads of companies, I applied to a wave power company in Edinburgh, lots of other ones, but there isn't that many jobs in renewables. I applied to Rolls Royce as well. So I ended up working there as an intern. For half a year, I worked on defense, I worked on a ridiculous project, a vertical takeoff and landing fighter jet called the Joint Strike Fighter. This is the most expensive program in the history of humanity, as far as I'm aware. And I was doing the control system for the exhaust at the back that swivels about 90 degrees, [which] means it can land. I loved a lot of it but like I was never blind to the fact that aircraft are one of the most polluting things, and there's a huge environmental impact. But I was I suppose, I don't know, naive or whatever. But I kind of thought, 'well, what I'll do, I'll go work on the future technology, what is the stuff that's gonna get us a 10%, 20%, 30% reduction in fuel burn, I'll go work on the stuff for 10, 20 years time. And if I can be part of delivering that, it's got a high impact, but if I can reduce that by 10%, that will be massive'. And I started to realise that that's not the case, that there's a lot of techno optimism around and this idea that technology will save us, but actually, we need the policies. Otherwise, we're completely screwed. And I became quite vocal within the company. You know, I was leading a project called the variable pitch fan. Basically, when engines get to really large size, in order to make them more efficient, the performance of the fan, the big blades at the front of the engine, there's a big difference between sea level and cruise. You end up having to have a variable pitch fan that changes angle, different angle at sea level compared to cruise. And this is a really complex thing, as you can imagine to design. It would take 15, 20 years to design, develop and produce. But we were putting no resource on it. We'd need fan designers, we'd need mechanical transmission designers for the bearings and swivel stuff we'd need really complex aerodynamics. And you know, it'd cost tens of billions to develop a new engine that's completely different like that. But we were only putting a few people part time on it. And I was like, 'why is this?' So then I realised as well, a variable patch fan was designed and manufactured by Rolls Royce back in the 1970s or'80s. And it was tested. And that was the latest data we had from it, before like computers were even being used. And so was the open rotor, which is another concept that flew in the '80s. And I was like 'why?' Why were we working on this stuff that we're talking about as a pipe dream now for 20 years time? We were working out in the '80s. Why was that? It was because the oil price was high because of the OPEC crisis. And that's when wind turbines were developed as well. It was a big rush in America to develop wind turbines. And that dropped off completely when the oil price crashed again in the '90s. All of that stuff was shelved. And that made me realise we know what technology to work on and we would work on it, if the conditions were right, if the market conditions are right. And this is the thing, it's all down to like what we're assuming will happen in the future. And basically, Rolls Royce and Airbus and Boeing are assuming we'll have cheap jet fuel to burn in 15, 20 years time and it all comes down to this. Cheap fuel and the emissions that aren't priced. So I was sort of saying 'why don't we plan for this?' and talking to the CEO talking to the Chief Technology Officer, and they were avoiding my questions, you know. And what happened is Extinction Rebellion happened in 2019. Suddenly climate was back on the political agenda. We have a climate emergency being declared. Even bigger than that you had Greta sail across the Atlantic rather than fly. And people were putting out stuff in the papers regularly about, you know, is it appropriate to be flying in a climate emergency? And this made the industry worried, I think. I thought this was great. I was like 'finally, some leverage'. What happened though, is all of the main aerospace manufacturers, so Airbus, Boeing, Rolls Royce, Safran, the French company, General Electric, and Pratt and Whitney, the American engine manufacturers, Dassault systems, the French manufacturer, they are kind of like basically the main competitors in this space. And they got together at the Paris Air Show in 2019, put out their sustainability strategy together a joint statement saying, 'don't worry about us, you don't need to regulate us, you wouldn't want to fly less, like that would be really bad for the world, we'd be heading to a dark place. Aviation connects cultures, it connects families, it stops international conflict. And anyway, it's only a tiny part of the problem. And we've got the solutions in hand, we've got more efficient technology, we've got electric aircraft, hydrogen will come in, we've got alternative fuels, like biofuels and electro fuels, and everything else we'll offset. And here's a roadmap'. And after that you've got every company coming out with their own version of the roadmap, but they all have those themes on them. And they all looked pretty similar. And also, I started to realise these roadmaps were very similar to the roadmap Shell had put out for the industry. So Shell, I think, from my observation of this over the years, Shell are the thought leaders, and aerospace manufacturers follow suit, and they take the narratives that have been carefully crafted by Shell, Shell in particular, and just re-format that for their own use. And this made me like, incredibly uncomfortable. And so I set up an employee sustainability group within the company, to challenge the corporate strategy, go through each of those themes, bit by bit. We went away and researched stuff. I did a kind of lunchtime talk to begin with, got people interested in this issue, Rolls Royce and the climate crisis, and then formed a group, people that were interested, and we kind of presented to each other, we got the corporate sustainability team, and we said, look, this is what we found out about hydrogen aircraft. These are the issues. We don't think this is a credible part of the strategy, tell us why we're wrong. And they really struggled with that. And that's when you know, you're onto something. Yeah. When people are like, 'actually, I don't want to talk to you anymore'. And they're a colleague, they're working at the same company. And they are stonewalling you, you know that you're onto something then. There was voluntary severance available, though, because they were trying to get rid of thousands of people. So I thought, I'll take a chance and I will take the payout and leave. And that's how it all started. And then two years later, I'm still doing this stuff.

Alasdair: 7:32

I think you've raised quite a lot of subjects already about about industry, etc. But maybe just before that, it'd be good for listeners if you could just give an overall picture of the problems with aviation and its impacts on climate, and maybe about, you know, the extent of the problem and where you think things are going. When I'm talking about that I mean right up until the end of this century if that's possible.

Finlay: 7:56

Well, so aviation is like a really large growth sector, right. I think that's important, that it's the trajectory, is what's important. So if you look at historically, like 50 years ago, there wasn't many aircraft. But every 15 years, air traffic doubles. And this has meant that emissions are on this really like almost exponential trajectory up way. The industry always starts by saying aviation is only 2 to 3% of global CO2 emissions. And that is a very effective strategy because a lot of people in the industry hear that and they think, 'no problem. Aviation, we don't need to focus on that. Look at road transport. That's 20%. Agriculture is 20%. The energy sector is 20%. Focus on those things instead.' The thing about aviation is emissions intensity. So like road transport is 15, 20% of emissions rather than 2%. But that's because there's like one and a half billion cars in the world. There's only 20,000 airliners. So each one of those is producing so much more emissions at such a faster rate as well, like most cars don't drive around very often. An aircraft is in like continual use throughout the day, apart from when it's unloading and reloading passengers. The first thing I always say though - 3% of emissions sounds small. It's not small, like the UK is 1%, right? And we're not saying 'it doesn't matter what the UK does'. 3% is larger than the entire country's emissions of the UK or Mexico or Germany. It's huge. And then also it's growing. So it's on this growth trajectory, where if you look at current trends, we've got decarbonisation and road transport and in buildings and agriculture, we'll see these things go down. Aviation doesn't have a decarbonisation strategy that will allow that so we're currently on track for aviation to consume a quarter of the CO2 budget. And then you say it's not just CO2, it's also non-CO2. And you've got stuff like NOx but in particular contrail cirrus that form behind the aircraft, they're like clouds, they blanket the earth as well and they stop heat radiating out at nighttime into space. So the latest science is that actually you've got to like triple the CO2 impact to get the total climate impact, including the non-CO2 element. It's sort of more complicated than that, because the contrails are short lived, they disappear in a few days. But the problem is we fly continually. So that's kind of irrelevant. And it means that you should basically triple it. Then the other thing is the inequality of those emissions. So it's basically a small section of society, like 1% of people produce half of all aviation emissions. Even in the UK, there's a large inequality, 50% of the UK population, this is the same in the US and the same in a lot of like developed countries, basically, half the population don't fly at all. And then those that do, you've got the next 30% of the population, and they do like one or two flights. And often it's a short distance, they don't fly frequently, and they don't fly far. And then you've got a tiny minority of the population that are flying 6,7,8 times, and there'll be flying to like, the other side of the world often, and they'll be flying on a monthly basis. So they really rack up the air miles, and they rack up the carbon emissions. So when you look at the UK, the CO2 emissions are like 8% of CO2 emissions. So it's already a lot higher here, and probably about 15% of the total climate impact if you pick up the countrails. And so it's not a small problem, basically, it's a large one, and it's a very unequitable problem as well.

Alasdair: 11:22

And in terms of why we're here, if you could just go a little bit into that, and then maybe we'll go into some of the kind of solutions.

Finlay: 11:30

It doesn't have any near term technological solutions. So the industry has been very much trying to prevent anybody looking at policy, and actually sort of governments, right. So historically, it's worth thinking, taking you back to the 1950s, or just after the Second World War, if you think about it it was the major superpowers, like US, UK, Russia, Germany, that had developed aircraft, like jet powered aircraft were just coming in at the end of World War Two. And suddenly, you could travel to other parts of the world to do business, right. And if you think about that, from the perspective of the UK and the US, for example, they want to go and fly into the country do business, like 'let's go to Nigeria, let's set up oil and gas stuff there. We want to fly in, do business, fly back. We don't want these countries to be taxing us. We want to be doing this'. So there was an agreement called the Chicago convention that was basically a moratorium on taxing jet fuel. And that basically still exists today. Although it's not that, like any country could tax jet fuel if they want to. Most countries choose not to, and kind of cite this convention as the reason, even though that's not really the reason because some countries do tax jet fuel and it's fine. So that's the historic thing, then you've got to understand in some countries, there is an emissions trading system, like in Canada and California and Europe. So in Europe, there's the ETS emissions trading system within the EU. When this first came into play, I think it was back in like 2010, it was proposed that international flights that were departing or arriving in Europe would also have this emissions price applied, not just internally inside Europe. What happened was China and the US kicked up a massive fuss about this. They said 'we don't want to have our passengers taxed more and then Europe are collecting this money'. And basically, they were like,'we're gonna impose sanctions, etc.' and the EU backed down and they stopped it basically. And it meant the emissions trading system was limited to just intra-EU and not extra-EU. Because of that it was then said, 'this is a sensitive political topic. So what we're going to do is we're going to give accountability for regulating aviation emissions to the UN body called ICAO', like I.C.A.O. (international committee for international aviation) 'and they have like five years to come up with something'. And this was like back in 2012. So fast forward to 2017 or so, and ICAO, who are UN bodies, so they've got 180 countries in there, including lots of climate deniers and countries with lots of fossil fuels like Saudi Arabia, and Australia and Qatar and stuff and Poland, those are some countries that like really helped water down the regulations. They came up with an offsetting scheme that was incredibly weak, incredibly ineffective, and just very, very cheap. And also, it just doesn't cover the majority of emissions. That was agreed a few years ago. It was just meant to start kind of in 2020. And it's going to last until like mid-2030s. And this is like a completely, widely recognised as a completely inappropriate policy mechanism basically. It's not going to stop the growth of emissions at all. And basically, it's unlikely to make any dent whatsoever in emissions. So that's where we are today. We've got the ICAO conference coming up at the end of the month, and they're likely just to basically all of the conversation is whether to make the baseline year 2020 rather than 2019. It's not to like completely reform the policy, which is what's required, in my opinion. So that's kind of the historic background to emissions and why they just keep on increasing and why there isn't the policy levers to make the manufacturers go faster and to radically change the way we fly.

Alasdair: 15:12

So essentially progress is close to non-existent? Is that fair to say?

Finlay: 15:19

Yeah, and I think the other thing I should have said is the Paris Agreement, a lot of countries have to submit nationally determined contributions under the Paris Agreement, which are voluntary promises to reduce emissions by a certain amount. Now, it's interesting because the wording of the Paris Agreement say'economy wide emissions', which no one's arguing that aviation doesn't, like affect the economy. A lot of NGOs say it should be included. But the reality is, most countries don't include it in their submissions. No country does. Only the UK is committed to including it, but not until the 2030s. That's another problem as well. It's literally not accounted for and countries don't take responsibility for what happens in international airspace.

Alasdair: 16:00

There's been a lot of talk about things like sustainable aviation fuels, obviously you've mentioned offsets, there are efficiency improvements, etc. Could you go over some of perhaps what you see as maybe some of the false solutions, then maybe go into some of the more practical ones, achievable ones?

Finlay: 16:17

I'll go with efficiency improvements first, right. We've got jet engine powered aircraft or tube and wing aircraft, we've been making these more efficient for the last 50 years, more aerodynamic, we've been putting lighter materials in. We've been putting in more thermodynamically and propulsive efficiency, better engines on the wings. It's really difficult. This is the stuff I was working on. Really, really difficult to get, like a few percentage of efficiency improvement reducing fuel burn. That has been achieved, though. But it's worth just saying,'okay, well, that's look historically'. The aircraft today are 15% more efficient than they were in the year 2000. Have emissions gone down? No, they've not they've like doubled. Why is that? It's because air traffic is more than doubled in the same time. So the industry knows that if you say 10% less fuel burn, people think you're burning 10% less fuel. But you're obviously just not though, because you're flying twice as much. If there was 100 flights this year and 100 flights next year, and we made things more efficient then great. But the market needs to be constrained. In an unconstrained market, then actually what happens is efficiency improvements make flying cheaper, and people are flying more frequently and more further when they do. Even with the same number of flights, rather than bank your efficiency improvements flying to the same places you can fly slightly farther on the same tank of fuel. And you've not changed a thing. And this literally happens, you're seeing those trends. So because of something called the rebound effect, you could literally be supercharging the emissions growth using the efficiency improvements. So really important to understand efficiency improvements are good, because they allow you to do more of something while using less, but only if there's a limit and a constraint on the market. And fundamentally, we need to cap and reduce every year, it's not going to work otherwise. The next thing is alternative propulsion right, electric and hydrogen. Electric, you've got batteries powering an electric motor. The problem here is weight, and volume actually for batteries. Just to give you an order of magnitude on understanding, battery's about 50 times worse than jet fuel. On the positive side for electric you've got more efficient motors that are about twice as efficient. But you're still looking at a twenty five to one ratio. And also, jet fuel burns off. So if you fly New York to London, halfway across the Atlantic, you've burned off half your fuel weight, roughly. Batteries could discharge, you don't lose mass. So this really limits the payload and the range of electric aircraft. You're looking at like sub 500 kilometers, which is really not very far. And like 10, 20 passengers at most. So it's really not a competitor to existing airline models. Where you can fly electrically, there's probably a ground transport option that's a lot more efficient use of electrical energy, it's probably going to be useful for niche cases where you're going to an island or you're in Norway where it's mountainous, but they're not going to make a dent in current aviation emissions. It's like a new market. Hydrogen is much the same. It's got different properties so it's much better on weight. But the problem is it's four times the volume of jet fuel. And that's even when you've not just hydrogen gas, but when you liquefy the hydrogen, you've got to cool it down to minus 250 degrees C, you've got like these really complex tanks, and then even then it's four times the volume. So you can't fit the fuel in the wings like you can with jet fuel, it's got to probably go on the fuselage, the wings need to be completely redesigned. The hydrogen will need to probably displace passengers or you need to make the aircraft bigger, and then you end up with aircraft that are heavier and larger, they've got more drag, and it's just a less efficient way to travel. The thing about hydrogen though is obviously it just produces water and no CO2. As long as you get green hydrogen in the sufficient quantities that don't come from fossil fuels. At the moment for like the foreseeable future, it's going to take decades just to decarbonise existing uses of fossil fuel to make hydrogen. And we should be doing that as a priority, not using it for aviation, in my opinion. But then just timescales, right? So 15, 20 years to design an aircraft, probably not a very long haul aircraft either. So we're going to have blown our carbon budget before the first large hydrogen aircraft is even out of the first factory, and then you've got a market penetration time of like 20, 25 years. So hydrogen, after 2050s, we're probably going to be flying hydrogen, at like a medium range at least. But we probably need completely different aircraft, possibly very different airport. And we need to wait for there to be sufficient quantities of hydrogen, which is going to be a long time off. Then you've got alternative fuels, so you say'it's going to take too long to redesign aircraft and change the configuration of airports - can we not just keep on burning oil, but not get that oil, not derive the oil from fossil fuel?' There's two ways of doing that. You've got biofuels and you've got electro fuels, which use renewable electricity. Biofuels first. Traditionally, most biofuels are from crops, crop based, and they're oil. So they're rapeseed, soy, palm oil, etc. And there's been lots of studies that show crop-based biofuels are actively damaging for the environment, because of the associated land use change. The water pollution that could cause deforestation, often peat bogs are drained, etc., you lose biodiversity. The studies show that they're literally like worse than burning fossil fuel. When I put this towards the industry and said, 'are you going to rule [it] out?' they often say, 'well, the government will have a sustainability criteria. Surely you don't think that the government would allow us to burn unsustainable feedstocks?' And so okay, well let's just have a look at the CORSIA scheme, which the UN have put in place. [It] does not rule out crop-based biofuels. Neither does the latest UN thing that's just been passed. The IRA thing that Joe Manchin has finally let through, that permits crop-based biofuels. There's a large agricultural lobby group in the US obviously, and they want an outlet for their biofuels because road transport is getting electrified. So I don't think that's guaranteed at all that we want to use fuel from crops. But a lot of people in the industry to deal with this concern are saying 'we won't use crops, we'll just use from waste'. Now, one issue here is that we haven't actually demonstrated at any sort of commercial scale biofuel from waste apart from one pathway. And that pathway uses waste oil, or fats. And that is a very limited feedstock. Even if aviation got it all, you could only scale to like maximum of 5% of current jet fuel use, I'm not even talking about growth. And then you say, 'well actually do we not need that elsewhere?' What you see is, for example in the US, California has been pushing those sorts of fuels for its road transport. What happens is a lot of the waste oil from around the US is directed to California instead. And people that were using that waste oil for something else before in the economy are now importing palm oil, and then you get the land use change still, right? So there's really constrained market and if you incentivise waste oil, you incentivise the chance of there being fraud with people using virgin palm oil, or rapeseed, or soy or whatever instead. I've done some work looking at [the] biggest biofuel refinery to be built in the southern hemisphere, in Paraguay. It's being built right on the edge of a rainforest. It's the most deforested rainforest region in South America. There's soy that's being planted and there's lots of livestock, which is terrible for the environment, but they're using the waste fat from the slaughterhouses and they're using soy to make this so called sustainable aviation fuel, which there's offtake agreements from BP and from Shell not to use in Paraguay, but to ship to the US and Europe for use in aircraft. Pretty skeptical about that, but it's literally a dead end pathway. And then the next thing to say is, they talk about agricultural waste, municipal waste from cities, and forestry waste from chopping down trees, and then you've got the bark and the twigs and the leaves and the sawdust. These things are really difficult to collect, because they're really disparate. You can imagine some sawdust in the middle of a forest in the middle of nowhere, you've got to collect that, ship it. It's not energy-dense like oil is. [It needs] a processing facility. If you go any sort of distance, you start increasing your emissions and ruling it out. So it's actually really difficult to do. It's never been demonstrated commercially. There's been lots of promises. The industry has been talking about this for 15 years. They've never delivered anything with these feedstocks. The technology hasn't been demonstrated, but we're banking the entire industry on it. And then you say 'even if it was demonstrated, do we not need the feedstocks elsewhere?' So ground transport, like long-range trucks and ships are also really struggling to decarbonise, it's a much more efficient use of biomass there. Obviously, if there is biomass, leaves, twigs, agricultural waste on the ground, you can make that into organic fertiliser to help displace fossil fuel fertiliser. Even if you can get some in for energy and you're not using it for road transport, bioenergy, carbon capture and storage, if you look at what governments are planning there, so risky, we're going to end up needing to use crops to fuel for that. The only way to minimise that is to try and use waste streams. And that's what they're assuming there as well. So there's nobody, nobody, no government that's sitting down and doing the cross-sector analysis, looking at requirements. And when you do this you realise that aviation is the most inefficient use of biomass as well. So if you're in some hierarchy, based on social need, and social distribution, it's not what you do. And this basically is mirrored when you look at electro fuels, because that's using renewable energy.

Alasdair: 25:39

Can I just ask on the biofuels I mean, if we're looking at aviation, the future of planes that are being developed for the future, what proportion are we looking at that at the moment would be using biofuels at the moment, if we were going on kind of existing models?

Finlay: 25:54

At the moment, sustainable aviation fuel use is like 0.01% of total jet fuel use. So 99.9% fossil fuel today, despite promises over the past more than a decade, like if you go back and look at industry presentation from 2007, they said we'd be using 10% sustainable aviation fuel today, in 2020. And we're at like 100 times, or 1000 times less than that. So there's a history of broken promises here. And they all say, 'oh, it's because they're too expensive. The government hasn't made them cheap enough.' But then the industry's spent the last 15 years growing massively. Actually, a lot of the big airlines have made a lot of profits and they've just sent it back to their shareholders as dividends and share buybacks. They haven't invested in new technology, haven't invested in fuels, because there's no policy that mandates them to. That's why we are where we are with that. And now we're having to bank on technology that hasn't been proven, hasn't been scaled, to completely underpin the sustainability strategy for the industry, which is obviously pretty dangerous.

Alasdair: 26:56

Are biofuels presented as one of the, you know, is it the biggest alternative that's being presented by industry at the moment?

Finlay: 27:03

Absolutely, although they don't like using the term'biofuels' because a lot of people that know something about environment know that biofuels can be very dangerous. So there was a strategic shift shortly after 2010, where you saw a switch from 'aviation biofuels' or 'advanced biofuels', that sort of terminology, to'sustainable aviation fuel', or SAF and this is a very convenient thing because to me, this is like the absolute prime masterclass of greenwash. And my reading of this situation is it was masterminded by Shell as well, because it's them that pushed this phrase most consistently from an early stage. But it's really clever, because if you say 'sustainable aviation fuel', then someone's like, 'okay, it's sustainable'. That basically means you start off with some electrical energy, you apply that to some water, electrolysis to produce green hydrogen, you also use that renewable energy or use that electrical energy, could be nuclear, it could be from any energy source, right, you have direct air capture, which sucks carbon from the atmosphere and collects it, you can then combine your carbon and your hydrogen in a process called Fischer-Tropsch, or the FT process. That synthesises the carbon with the hydrogen to produce a hydrocarbon that then produces this kind of crude oil, synthetic crude oil, which you then distill into jet fuel and actually have to distill it into other stuff. The industry doesn't like talking about that either because you can't just produce pure jet fuel so you need even more electrical energy than you think. The thing about everything I described there is every single process in that chain is highly, highly inefficient. So electrolysis, you tend to chuck away 30% of your energy right there. Direct air capture is very energy intensive as well, because carbon is so diffuse, and you need to apply heat so often you have pellets that capture the carbon, and then you have to apply heat to take that off to release the carbon again. So you end up using lots of energy. There's lots of kind of contrasting evidence about the power to liquid efficiency here but a good rule of thumb is like, you'd probably chuck away more than half of your energy getting to the fuel. And actually, the ones that run at the moment, you're looking at probably 25% efficiencies, so you chuck away three quarters. Now we might be able to get close to half efficiency. And probably you're at your thermodynamic limit, if you're 60% efficient. So you're going to chuck away at least 40% of your energy immediately. But then you also then go and burn it in a jet engine, which is 30% efficient, and it's the most inefficient way to travel. So in terms of power to thrust, to actually thrust delivered by the aircraft, you're looking at like 10% efficiency. So 90% of your energy's out the window. And it's like, you could have used that energy to decarbonise the grid, to power a heat pump to replace a gas boiler in the house, to power an electric vehicle to replace petrol or diesel and road transport, to make green hydrogen and use that for synthetic fertiliser to replace fossil fuel fertiliser, or even just to power direct air capture and just put the carbon in the ground and leave it there. All of those things are more efficient than making synthetic e-fuel. It's like probably the most inefficient thing you could do bar put it in a space rocket and send Jeff Bezos to outer space. The thing that the aviation industry and governments do not like talking about is the opportunity cost of using energy for one thing over another and only if your baseline is a false baseline where you're not doing anything with that energy anyway, which is unrealistic because low carbon energy is so scarce and will be for decades, you'll always have been better using it for something else. And actually I think - this isn't, by the way, an opinion that's out there- but when you work through it from an engineering perspective, I think you find it's far better just to burn jet fuel, and use low carbon energy for other stuff. Now, the industry doesn't like that because it looks bad. And also, it really shows that we just need to burn less jet fuel year on year. Burn jet fuel, but have it capped and burn less and less every year toward zero. And slowly your electric and your hydrogen and some alternative fuels, but limited quantities, will start replacing those. That's kind of the conclusion I end up at. And I've never seen a good rebuttal for that. And yeah, so the other thing is that actually, you produce this crude, and like, generally make about half of that at most into jet fuel. And then you're also left with some essentially, e-diesel, and e-naphtha, which is like natural gas. And the thing is it's so expensive, because it's so inefficient, it's like 5, 10 times the price of fossil fuel. So there's no way any airline is gonna, like, voluntarily use this. And also, they're talking about it, but they're not planning in 15 years time to be paying 5 times, 10 times more for the fuel. So it's what they're saying is completely inconsistent with their business models. And because of that distillate thing, the fact you only get a fraction, you end up needing even more energy. And I did a calculation recently for the UK, that showed you need the entire UK grid capacity just to make our current consumption of jet fuel. That's like three times all of the renewables, it would be an offshore wind area the size of Northern Ireland, or it would be like five times our current nuclear power capacity. A lot of people actually in the aviation industry say, 'oh, let's build lots of nuclear reactors'. Okay, that's going to take decades, forget the waste issues, who's paying for it? Are we going to tax jet fuel now to pay for nuclear power stations, because I don't see that in any of the strategies. So these are sort of conversations to get into just to give you some context on the size of the problem here.

Alasdair: 32:35

And I think that brings us quite neatly on to the practical policy, it sounds to me like you're heading basically towards saying, taking out flying altogether?

Finlay: 32:43

Unequivocally, if you talk to a climate scientist, and anyone involved climate policy, they're just going to say, 'we need to fly less'. The important thing to say is 'the people that are going to fly less is the people that fly frequently'. So most people don't fly at all right? 80% of the world have never flown, so they're not going to be doing anything differently. Even in the UK, only a small portion of people do something differently. Whether we need to stop flying completely, like okay, that's a matter of debate. What I think is not a matter of debate is that we shouldn't double air traffic over the next 15 years. And that's our status quo. Right? So I'd say we need to challenge that.

Alasdair: 33:16

Like a frequent flyer levy is relatively straightforward. I just wondered where change might come from. There are some seeds of hope?

Finlay: 33:26

Who do you think has the biggest say within the UN? It's going to be the US, right? Not just the US but like the other major economies, the G7. Who flies the most? The G7, the people in power. Turkeys don't vote for Christmas, kind of saying right? If this was reversed, and rather than the G7, you had the bottom seven, they'd be like 'tax jet fuel!' And in fact, they have been saying that. They've been saying it for ages. Maldives proposed a minimum 2% tax on jet fuel back in 2008 or 2009. And that was hush hushed and not amplified at all by the media. So I think it's a matter of power dynamics. What we do, so UK and the US fly a lot more, and so do China as well, right? I put them in this category as well. And it's like we go for the...governments are just in this zone of like maximising, like high value productivity, like rather than give, like pay a bit of money to connect some like poor areas in the country more with bus services, train services, they'd rather incentivise like one extra business jet per day, landing near their capital city coming in and doing a big 100 million pound or dollar financial transaction, they can tax higher and like that, and that's the way like things consolidate, always like tripping over ourselves to try and reduce tax for the wealthiest in society and the wealthiest in society are also the highest energy users. That is this power dynamic that we need to address if we're going to address climate change. That is going to come from low income groups realising they're being screwed over royally. Economically, already they are, but environmentally, that's only going to get worse, and that inequality will widen, and at some point it's going to snap, if it hasn't already.

Alasdair: 35:18

Thanks for Finlay for his time. We've also put up some suggested further reading for this topic on our podcast blurb. Please also feel free to give us a review or do get in touch with us if you have something climate related you think we should cover. Thanks for listening!