The Exchanges

Q think about this stuff, but just for a frame of reference, let's say we're taking a 20 year global warming potential, so nearer term than the hundred years that, you know, has been sort of de facto standard historically, um, but we're also normalizing hydrogen and methane for their energy content. Just where do they stack up against each other from what we know in terms of global warming potential?

A So, first of all, um, just on a per kilogram of gas comparison, when you look at, um, Hydrogen. On the hundred, as a hundred year equivalence basis, uh, you're looking at a global warming potential of 10. Um, but if you go similar to methane, when you go on a shorter lifetime here, you will, uh, have a higher number. So for natural gas, it goes from 25 to 80, roughly, from a, when you compare a hundred to 25. And for hydrogen, it goes from 10 to 40, so it increases substantially, but it's still half of the global warming impact, global warming potential of Natural gas per kilogram. But then hydrogen has a higher energy content of almost, or roughly, a 120 mega joules per kilogram, and natural gas is around 50. So there is a factor of two and a half again. So the first factor of two and then another factor of two and a half gives you a total factor of five in between.

AI assessment note: “So the first factor of two and then another factor of two and a half”

Q the science. There have been a few papers that have come out recently, both in the US and the UK, that have raised alarm bells to some degree regarding the possibility that hydrogen leakage into the atmosphere could Um, have a negative impact on, on climate change, have a warming effect on the planet. Can you just walk us through what that mechanism might be? Why would that be true?

A I will give it my best shot, acknowledging that I am not a scientist on this topic myself, but I've done my best to read up on published research and try to understand what it means. But I think the bottom line conclusion is that, um, hydrogen Seems to have a higher global warming impact than what we previously thought. There has, I mean, if you go back in the tables that have been developed by the IPCC process and used in all the national inventories for, for hydrogen leakage, the number has been, uh, significantly lower than some of the recent research suggests. And there are a couple of things happening here, and mostly it's the To my understanding, the secondary or indirect effect that has been neglected previously, so basically what happens is that the hydrogen that leaks has itself a global warming potential, which has been, um, considered, but then also, um, it has an effect of extending the lifetime of methane in the atmosphere, uh, basically causing the methane to stick around longer, and that Has obvious effects on the greenhouse, uh, sort of the global warming impact of that methane. And then, uh, I think that there is also some, um, interaction with the ozone layer that has, um, as a consequence that the hydrogen creates Stratospheric water vapor, which has another indirect effect on global warming.

AI assessment note: “it has an effect of extending the lifetime of methane in the atmosphere”

Q leakage in that system, and because there are credible alternatives there. Whereas heavy industry, fewer credible alternatives, You know, less pipes that could be leaky pipes, less likely to have as much leakage. Do you, is it, first of all, do you think that I'm, uh, coming up with the right conclusion there, and do you think that that is generally agreed upon, or is that still up for debate?

A That was a, that was a long and leading question, I guess, but, uh, and, and I, look, I, I would argue the same, like, with the only slight difference, that in, in that conclusion, I don't think the leakage is sort of the dominating criteria, because, you know, yes, we want to avoid Leakage, but there are other reasons to prioritize hydrogen use in the sectors where we have, you know, You know, not very many other alternatives or where direct electrification is not easily implemented from fundamental economics and from the fact that I think that in the, in this transition, the renewable energy supply will be one of our biggest sort of system level bottlenecks, and we want to get the most out of each electron we get out of our wind turbines and solar farms. So from that perspective as well, you want to Use, um, those directly as much as you can, instead of transforming it to hydrogen, and then potentially transforming it again. So, I think, for me, the rationale is fundamentally from, um, you know, basic Energy efficiency. And then secondly, from a business perspective of where you get the most bang for the buck, if you like. And then that happens to correlate quite well with where we're likely to have less leakage. So that's what I mean, right? You know, I, I think we're, We have very similar conclusions in terms of priorities and implications of the findings of this, um, this …

AI assessment note: “I would argue the same, like, with the only slight difference”

Q it comes down to the assumptions in those studies that, Which are pretty variable, and what that implies in terms of how big a deal it would be if we scale up hydrogen within our economy. So can you just talk a little bit at the high level about sort of what are we assuming in these studies, and how does that impact what the, what the results would be?

A Well, I think you can look at the transition in, uh, a little bit, a few different ways, and I, um, you can either have as a starting point assumption that everything goes wrong, or you can have a starting point assumption that, um, we will broadly figure things out, and I think that starting point makes a difference, and whether you're sort of looking for the, um, Um, unintended consequences that we need to avoid, or whether you're looking for the good solutions that we want to promote, right? And, and that has, uh, some bearing on what assumptions you make, I think. And I haven't seen all the research that you're referring to, but I think, um, some of the papers I have seen seem to assume that Very large adoption rates for hydrogen in the economy, for example, which I think many of us who work with hydrogen a lot would consider to be a big number, which is unlikely as an outcome, but then again, if you do assume such a scenario and you apply very big global warming potential to those, you know, that consumption with a reasonably high leakage rate, then the conclusion Gives you, you know, the fact base for a big headline, right?

AI assessment note: “some of the papers I have seen seem to assume that Very large adoption rates”

Q be really high leakage rates, like 10%. How much do we know about likely hydrogen leakage rates? Should we be concerned about 10% plus leakage and the implications that that would carry? Is this just a call to arms for regulation? Uh, to do sort of at the front end what we didn't do at the front end with, with methane, or how do you think about the leakage rate?

A So it's partly true that we don't know, because these systems have not been built out, and it's also true that if we build them out poorly, we will have a lot of leakage. Now, I guess the, the big question here is what are the, Drivers or rationales for industry to build a very tight system, which will have some marginal capital expenditure involved, right? Um, I think there are a couple of things that are speaking to Sorry, let me put it this way. I think it's natural here to compare to natural gas systems, because that's a, um, a gas transportation system or distribution system that we have implemented at scale. Um, the natural gas system is arguably leaking quite a bit, um, and there is reason, there are reasons to believe that hydrogen will leak more than Mostly from fundamentals of the size of the molecule and, and, and the properties thereof. But there are also reasons for, um, These systems to be less leaky, and I think one of the reasons that, and I'm stepping out here of sort of foundational science and peer-reviewed research, right, and, but I, but I think one of the rationales that I can relate to having been working in, in industry for quite some time is the safety aspects of leaking hydrogen, because the properties of leaking hydrogen is much more dangerous than, than leaking, Methane. Um, partly because it's, it's harder to detect. Uh, so, So that's one reason why…

AI assessment note: “it's partly true that we don't know, because these systems have not been built out”

Q out hydrogen infrastructure for the use cases where we think it does make sense then, um, how do you think about transportation? You know, are we going to be building out hydrogen pipelines, transmission pipelines, maybe even distribution pipelines, depending on the use cases? And, you know, one of the lessons that we need to take to minimize leakage, knowing that That that's something we care about in this context.

A So again, I think it's, uh, relevant to think about, um, the, the fundamental priorities here of, of number one, let's use the hydrogen where we have the biggest impact. And, uh, by a wide margin, a factor of two, um, that means we should use hydrogen for steelmaking. So using the hydrogen molecule for, uh, reducing iron ore Has twice as much, um, you know, impact on the alternative, compared to the alternative, um, If you benchmark with using it for transportation applications, and I bucket here shipping, aviation, and trucking. Roughly, you get the same impact from using hydrogen in these three sectors, because fundamentally it's the same physics, right? You're replacing an internal combustion engine running on hydrocarbons, moving something through inertia and, uh, or friction, and you're replacing it with a Fuel cell, um, with using hydrogen and, you know, net, you're doing roughly the same thing, you know. Um, and then you have the thermal application of burning hydrogen for heat, um, replacing either natural gas or coal or other heat sources, and that has yet another factor of two, roughly, less impact. So, from that perspective, we should use hydrogen for steel. Now, secondly, I think, again, we're, we're, what we're trying to achieve, at least in terms of, um, building an economy or an industry at scale, the increments of demand is also relevant, and you need roughly, y…

AI assessment note: “number one, let's use the hydrogen where we have the biggest impact”