Plan Sea: Ocean Interventions to Address Climate Change
Plan Sea is hosted by Wil Burns, Co-Director of the Institute for Responsible Carbon Removal at American University, and Anna Madlener, Senior Manager for monitoring, reporting, and verification (MRV) at the Carbon to Sea Initiative.
As co-hosts, Wil and Anna invite guests to the podcast each episode to discuss potential ocean-based climate solutions, particularly approaches that lead to carbon dioxide removal (CDR) from the atmosphere. The podcast scrutinizes risks and benefits of these options, as well as matters of governance, community engagement, ethics, and politics.
Plan Sea: Ocean Interventions to Address Climate Change
Dr. Phil Renforth and Dr. Mijndert Van der Spek on a harmonized framework for techno-economic analyses and lifecycle assessments of OAE
In this episode of Plan Sea, hosts Anna Madlener and Wil Burns sit down with Dr. Phil Renforth and Dr. Mijndert Van der Spek of Heriot-Watt University to unpack their newly published, harmonized framework for evaluating the viability of ocean alkalinity enhancement (OAE) pathways. Moving beyond lab-scale assumptions, their approach integrates techno-economic analysis (TEA) and lifecycle assessment (LCA) to allow the exploration of 54 known OAE variations and how they perform under future, decarbonized energy scenarios. The conversation highlights why real-world data, a cleaner energy grid, and feasibility assessments are important for determining which OAE pathways will deliver results in global scale carbon removal.
With any emerging solution, both feasibility and cost must be effectively evaluated. Renforth and Van der Spek combine two essential lenses – techno-economic analysis (TEA) and lifecycle assessment (LCA) – to build a comprehensive picture of OAE’s real potential. TEA determines if a pathway is economically viable and scalable, while LCA screens for its full environmental impacts, not only if it is net-negative, but also whether it engages in “burden shifting,” or solving one problem while creating another. Operating far beyond “carbon balancing,” LCA works across a range of categories, from greenhouse gas emissions to terrestrial and marine acidification, resource use, and pollution. Together, the two tools are meant to provide a level of quantification for decision-makers investigating the viability of any CDR approach.
In looking at the framework, Dr. Renforth and Dr. Van der Spek began by introducing the framework’s structure through a case study of BPMD and its functionality as OAE technology. Rather than offering predictions, the framework helps to show how different technologies perform under current assumptions. This means the framework should not be viewed as forecasting long-term outcomes on its own, but instead as a tool to see how each pathway changes.
While these tools are powerful, they are incomplete and alongside rigorous research into the broader social, regulatory, and ethical implications of each potential pathway. For example, LCA aims to measure global stressors by normalizing impacts, but it does not have the ability to detect localized effects. This highlights that any comparison drawn from the framework must be paired with site-specific environmental assessments. Together, these layers of analysis provide a more realistic understanding of where OAE pathways may be within reach.
Join us as we dive deeper into this framework and how it aims to spur further evaluation and innovation in OAE by listening to the episode above! Subscribe on your preferred podcast platform and find the entire series here.
ACRONYMS / CONCEPTS:
- CDR: Carbon Dioxide Removal
- OAE: ocean alkalinity enhancement
- TEA: Techno-Economic Analysis
- LCA: Lifecycle Assessment
- BPMED: Bipolar Membrane Electrodialysis
Plan Sea is a semi-weekly podcast exploring ocean-based climate solutions, brought to you by the Carbon to Sea Initiative & the American University Institute for Responsible Carbon Removal.
0:13 - Introduction & Why TEA/LCA Matter for Ocean CDR
Anna (00:13): Welcome to a new episode of Plan Sea: Ocean Interventions to Address Climate Change. I'm your host, Anna Madlener, Senior Manager for MRV at the Carbon to Sea Initiative. And with me is, as always, my co-host Wil Burns, who's the co-executive director of the Institute for Responsible Carbon Removal at American University. Good morning, Wil.
Wil (00:31): Hi, Anna.
Anna (00:31): We're here today to talk about a really critical but often somewhat overlooked aspect of exploring and evaluating carbon removal methods, a so-called technoeconomic analysis and life cycle assessments. So we're in for another nerdy topic. More specifically, Phil Renforth and Mijndert Van der Spek of the Harriet Watt University in Scotland are joining us to discuss a high-level harmonized framework they recently published to assess ocean alkalinity enhancement pathways from a cost and emissions perspective. Wil, do you want to share a bit why you were keen to talk about this topic today?
Wil (1:07): Yes, I heard discussion of this on another pod actually, and just thought that it was right in our wheelhouse. I mean, we've reached a point where I think not only do we have to assess whether from a theoretical perspective some of these MCDR options can sequester carbon, but also do they stand the test in terms of resulting in a net decrease in carbon dioxide from the atmosphere? And can they pencil out from an economic perspective and ultimately from a social perspective? And I thought this framework established a foundation for us to start looking at the critical metrics that are gonna have to be assessed.
Anna (1:58): Mm-hmm. Yeah, that makes sense. I would go along with all of the above, so to say. And also just add, I think this is going to be a really cool episode. As you know, Wil, and probably our listeners know, we love ourselves some good nerdy topics. And maybe this comes next after diving into MRV protocols for me. But in all honesty, I think it's super critical that we discuss it and talk about it. At the end of the day, as you said, we need to know if ocean alkalinity enhancement and frankly all other carbon removal pathways can be, or have a chance to be, cost effective and if operations will be net negative, as you alluded to. I'm quite interested in hearing from Phil and Mijndert how they envision this framework evolving and how it can guide evaluation, drive innovation, tease out assumptions where we can actually still improve upon and where we have a chance of solving or changing them in the near to midterm future, rather than sort of saying this doesn't work, this won't work. Because we don't really have all of that data yet to make that decision. So yeah, I'm very keen to hear how they balance that reality.
Wil (3:11): All right, so let's let's bring them in.
3:14 - Meet the Guests: Phil Renforth & Mijndert van der Spek
Anna (3:14): Hello, welcome Phil and Mijndert. It's great to have you here today. We want to start with a bit of introductions. And Phil, I was keen to start with you. I came across a page on Harriet Watts' website while preparing for this episode where you included like a chat GPT analysis or a summary of yourself. It mentioned a lot of things, including that you're a professor for carbon removal, and I was keen to hear more about that. I think not many people actually hold that title in the world. Do you know if you're the only one or are there more?
Phil (3:41) :I haven't checked actually. Someone asked me quite recently how much of my time do I spend on CDR on carbon dioxide removal? And I sort of felt a bit sheepish in answering because it's all of my time. So it's probably appropriate that I have that title. But then I suppose it's also kind of aspirational for me because it challenges me to sort of think about technologies that I don't think about too frequently from the wider CDR space. You know, I spend most of my time thinking about geochemical CDR. So I have to brush up on all of the others as well if I'm going to wear that title with pride.
Anna (4:24): Cool. I want to talk a little bit more quickly about your work and your background. I saw that your first paper on carbon dioxide removal dates back to 2009. So I felt that the overview of your papers is a nice testament of the maturation of the CDR field as a whole over the last two and a half decades. And at some point you started focusing on technoeconomic analysis and these types of process studies. What sparked your interest in this particular field of CDR?
Phil (4:55): Yeah, it's really interesting actually. For a long time it was largely crickets, which Wil will testament to, but over the last I think over the last sort of five years, I think I'm suffering from whiplash because it's sort of moved so quickly, which is, it’s wonderful and also does keep us on our toes and and make sure that we we can sort of keep up with it. I mean what drove me into the space in the first place is I'm an environmental engineer by training. And when I was sort of looking around and coming towards the end of my environmental engineering degree, I was sort of thinking about what to do next. And if you think about it, what we need to do with the atmosphere is essentially the largest remediation, environmental remediation project that we'll ever do as a species. So I thought it would be really interesting to be part of that.
Anna (5:52): Cool. And we'll have a chance to dive deeper in a bit. Mijndert, I want to welcome you too. Similarly, your background is a testament to how this CDR world has evolved. In your case, I was curious if you want to share a bit more about sort of the feasibility landscape of CDR in late 2025, and share a bit about your journey to this point in time.
Mijndert (06:16): That's kind of the million dollar question, isn't it? So let's not forget that CDR is happening, right? Albeit maybe not even that small of a scale, but CDR is happening in a sense. So anthropogenic human activities are drawing down CO2 beyond what would maybe naturally happen. To be able to do that, maybe we first needed to clear heaps of forest, etc. So I mean it depends a little bit where you put the system boundary and then, maybe I'm touching already upon something that is really important - so timescales and the boundaries of what you're looking at. I mean, of course CDR is feasible, otherwise we wouldn't be looking into it. If it was really a pipe dream, then there wouldn't be so much interest in it. But feasibility has many facets and I don't want to pre-empt your questions later. So how feasible something is something that we need to look really hard at.
Anna (7:14): Mm-hmm. Great. And I noticed that I specifically mentioned Phil's title and forgot to mention yours. Do you mind briefly sharing with our guests what you do at Harriet Watton?
Mijndert (07:25): Yeah, I'm an associate professor and then you don't get a title.But I teach in the the chemical and process engineering program.
7:35 - TEA vs LCA: Core Concepts & Environmental Trade-Offs
Wil (7:35): Let’s set the table a bit before we dive into the report itself. In essence, this report kind of weds technoeconomic and life cycle assessments. And I think at the outset it'd be important to define those terms in the context of marine carbon removal. So could you do that? What's technoeconomic and life cycle assessments when it comes to MCDR?
Mijndert (8:05): Yeah, maybe I can have a first go at that, Wil. And I mean, when developing a new technology or a new solution or a new anything, it doesn't matter whether you're a business or you're an entrepreneur or your government or a scientist like us, people ask about the feasibility, right? Because very often we want to focus on things that are indeed feasible and feasibility can have multiple aspects, but technoeconomic performance and and lifecycle environmental performance are two of them. And like I said, the range of people who might want to undertake analyses of a new idea or concept or technology can vary from businesses to governments to researchers. But the question is very often the same. Like, is this something that fits within our economic boundaries? Is this something that, has the potential to become economically feasible, as in, can we pay for this? And equally a question that's been asked more and more often is okay, does it do what it is supposed to do in terms of in this case, carbon removal or fighting ocean acidification? And what could be potential other side effects? Because ideally, we don't solve one problem by creating a massive other problem, right? So you want to do a screening of environmental impacts as well. So very briefly as a starting point, that's what technoeconomic analyses aim to investigate, and lifecycle assessments and in the context of ocean CDR, that's no different.
Phil (9:50): Yes. I'll use this opportunity and this platform to kind of dispel something that I hear all the time, and that's when folks talk about a life cycle assessment, they're often abbreviating to carbon balance. So sometimes when they think of life cycle assessment, what they're really just talking about is carbon balance. But the true value of a life cycle assessment is that it can analyze the environmental impacts across a range of categories, so not just carbon or climate change, but terrestrial and marine acidification, for instance. It depends which sort of method you use. It dictates what impacts you look at, but it can do a lot of other things other than global warming. And it's sort of as Mijndert says if you have that broad methodology, you can show or analyze what's called burden shifting. If you do something about CO2 or climate change, are you just shifting onto a different environmental impact? So that's just something that's worth clearing up from the start.
Wil (10:56): Yeah, I think that's a really important point from a standpoint of policymaking ultimately down the road, right? In terms of acknowledging co-benefits, acknowledging trade-offs, right? It's where we are. So you indicate in this report that if we're gonna fully assess the viability of any CDR approach, we're gonna need to consider multiple criteria. And this includes economic, environmental, and social factors. And one thing I was curious about in a broad sense is how does one quantify or weigh non-monetary sort of elements such as social acceptance?
Phil (11:36): I mean it's a good question, Wil. I suppose they're not necessarily included in these tools. One thing that I have heard about technoeconomic assessment and life cycle assessment is folks have said, Oh, we need these tools to make it easier for decision makers. And I think that's completely the wrong way of thinking about it. I think decision-making should be hard because you need to weigh up all of these types of factors. But technoeconomic assessment and life cycle assessment can enrich those that are decision-making with additional information. But it is really at that decision making level that one should try to include all of the other things that are important within that decision making. I mean, there are tools around LCA or social life cycle assessment that have been developed, but they're not what we included within the report.
Wil (12:44): Anything to add there, Mijndert?
Mijndert (12:47): Yeah, it's very difficult, isn't it, this question, and there's certainly no unionary answer to that, how much weight you give to certain elements, right? So for instance, social justice or equity or public acceptance versus the cost of something or the environmental performance – and very often environmental performance very much relates to justice questions – but how heavily you weigh each of these is very value laden, right? In policy analysis that's not objective, that's subjective, and it will really depend on the person who's trying to make the decision. So I wouldn't argue for standard weighting of all of these kinds of things. I think that different organizations will make their own trade-offs, where each of these things should have a role. And yeah, as Phil said, what we can do with technoeconomic and life cycle assessment is provide some quantification that people sometimes find a bit easier to to to look at some numbers, but that should really not be the only thing that's taken into consideration.
13:57 - The Harmonized Framework & OAE Pathways
Wil (13:57): So one of the things that the framework necessarily does is it utilizes – or maybe it doesn't necessarily have to, but I think it was salutary that it did – it uses something called future oriented analysis, right? That tries to assess the trajectory of future costs in terms of ocean alkalinity enhancement as well as capabilities of ameliorating impacts. And I was curious if you have examples of other technologies where utilizing this analysis has proven to be reasonably accurate in helping us to tease out those kind of trajectories.
Mijndert (14:42): When reading that question, my first half joking answer was none. But let me also explain why that was the first thing that came to mind. I mean, so I think we need to be very very aware of the fact that you can never predict the future very well, right? That it's difficult to predict things, especially when it's about the future. And maybe accuracy of prediction is also not exactly what you want to talk about. What I think we know for a fact is that previously, or maybe up to a couple of years ago, the technoeconomic and life cycle assessments were done as if a technology already existed, which for many of these technologies, is not the case, and for the current situation. And luckily, and that's not something that we have done by ourselves - especially the LCA field has moved towards something that's called prospective LCA, where they're trying to understand in certain futures how the environmental performance of a technology may change. And I think our contribution is that we have now merged that prospective thinking from the lifecycle assessment field with the similar prospective thinking in technoeconomics, so that we can give a more integrated, holistic kind of view. And I think what – again, I'm not going to say that our answers are going to be 100% accurate because I think if anything, they're going to be a hundred percent uncertain. But for a certain consistent set of future assumptions, think for instance of Intergovernmental Panel on Climate Change scenarios, we can give a reasonable estimate of how technologies may evolve over time. And we can also give a reasonable comparison of how different technologies may trade off against each other. And I think that that is the big gain of looking at these type of technologies in a harmonized, future oriented, integrated manner.
Anna (16:45): So somewhat building off of that, I want to dive into the report itself and the framework that you developed. For full disclosure, it was partly funded by the Carbon to Sea Initiative. And the report introduces a harmonized framework of technoeconomic and lifecycle assessments, and it's 200 pages. It's a wealthy document. For folks who haven't read it or who maybe don't have time to to dive into all 200 pages, can you add a little bit more about – building on what you just just shared already – what folks should keep in mind for sort of the rest of the episode, what the report is, who is it for, and what is it not?
Phil (17:28): Two hundred pages is some nice bedtime reading. I'll just give you a quite a quick summary. So where this this came from was, and I suppose Mijndert alluded to it in in his last answer to the question, was there's a lot of best practice out there for how we do technology assessment like life cycle assessment and technoeconomic assessment, but that really hadn't been applied to ocean alkalinity enhancement. So that's a criticism of my work, my earlier work more than anyone else's actually. It's just the case that we really didn't bring some of that best practice in previously. So we saw this as a good opportunity to try and take what we knew from some of Mijndert’s previous work on technoeconomic assessment, and what we knew about the good best practice in LCA and just bring it into assessing ocean alkalinity enhancement. And I think that was our original intention. What kind of happened along the way is we sort of innovated along the methodology and sort of coming up with this idea of prospective technoeconomic assessment, which I think was a really interesting outcome. In terms of who it's for, well, I think it's for anyone who really wants to make a decision on ocean alkalinity enhancement technology. So it's for academics, but it's for commercial operators, it's for investors, for buyers, it's for anyone who really needs to be thinking about the performance or feasibility of ocean alkalinity enhancement.
Anna (18:58):Okay. And I'm going to circle back to that probably again later in terms of making decisions for sure. Before we do that, you identify forty-five different ocean alkalinity enhancement variations in the report, I think, depending on the source of alkalinity, the transformation process, pathway to the ocean. How did you sort of arrive at that structure? And how did you end up working with that structure? And how did it sort of guide your comparisons?
Phil (19:27): Yeah, I think the motivating factor behind arriving at this array of technologies is that I think often when folks are talking about ocean alkalinity enhancement, they have something specific in mind. So they might be talking about or thinking about one specific pathway. What I think we really wanted to do was just demonstrate that it's actually quite a rich array of technology options that actually function quite differently from each other. And that's important to highlight that because the form and function of the approaches or the pathways, technologies, really dictates their feasibility, but then also their environmental impact as well. So they don't behave the same way. So this number, fifty-four, I think it was, variations in technologies. We sort of separated it out into four families. So rather than being too complicated and too diverse, the four families that we sort of came up with were enhanced weathering – that's the idea of taking minerals, rocks, materials, and without too much transformation, adding them to the ocean, then there's a sort of thermal transformation process, which a lot of people call ocean liming. So it's taking feedstocks and transforming them into things that you might add to the ocean through a thermal transformation. Then there's a sort of chemical transformation processes, so feedstocks going into a chemical transformation and really trying to extract the alkalinity from the material to add it to the ocean. And then the fourth family is electrochemical approaches that use essentially electricity to create alkalinity.
21:24 - Case Study: BPMED, Energy Needs & Future Scenario
Wil (21:24): So let's talk a bit about the actual framework and applying it and the novel work that you did here. So the published report presents a case study for bipolar membrane electrodialysis, which for obvious reasons I'll shorten to BPMED for the rest of this. Have you applied this framework to other ocean alkalinity enhancement pathways since initial publication of the framework?
Phil (21:59):Yeah, I would – for explanation, bipolar membrane electrodialysis is an electrochemical approach and the way it works is you have an electrochemical cell that's separated by a bunch of membranes inside and you apply voltage across that cell, and if in the middle of it you add a a brine, the voltage essentially splits that brine into an acid and base stream. And if you take the acid stream and you neutralize it, so if you react the acid with let's say silicate rock, you're essentially left with a base stream that you can add to the ocean to increase its alkalinity. So that's sort of how BPMED functions. And yeah, BPMED is a really interesting case study because it exemplifies the importance of this prospective approach because it's really hungry for electricity. And if that electricity isn't decarbonized, which in most places in the world it isn't, it's not really a net negative approach. And you only see it become net negative as the grid decarbonizes. So that's a really good example of this sort of prospective approach, that if we show the scenario of grid decarbonization, do we start to see it actually as a functional ocean alkalinity enhancement technology? And yeah, we're planning to apply it to a whole range of other case studies. We've got something around hydrated carbonates, using hydrated minerals for ocean alkalinity enhancement in the works. I think by the end of our project, we'll have five, I think, case studies, ocean alkalinity enhancement case studies. But we're also hoping to apply it to a range of other CDR approaches beyond ocean alkalinity enhancement. And we've already applied it to looking at mine waste carbonation, so looking at using mine wastes to capture atmospheric CO2. And I imagine that this type of framework could be applied even more widely than that.
Wil (24:09): Yeah. Now you mentioned already that at least at this point BPMED is not net negative in the base case, I guess primarily premised on energy needs and the current mix of energy. And you indicated that was true for coastal enhanced weathering also. Are there other assumptions behind this that lead you to believe that in the future it would be net negative beyond assumptions associated with the energy mix?
Mijndert (24:45): Maybe I can give a bit of an answer to that one. So, the short answer is yes, but equally no, right? So we know that CDR technologies in general can be indeed energy hungry, and it really depends on which technology we're looking at. Very often the more engineered technologies do require a bit of energy. And we know very well what are the energy costs currently, because we can just look it up on spot market prices or power purchase agreements or long-term contracts. And we also know what the energy intensities are across the globe, right? So first and foremost, when you make such an assertion, it's always important to look at different countries and regions to see where that applies. Then of course there go assumptions – and these assumptions can quite literally be assumptions, but it can also be the result of more detailed modeling work – go into lifecycle assessments. So that's definitely true. But at the same time, these technologies also will develop over time, right? So we know that with most energy technologies, but not just that, also with electronics and with many other things, when we produce things kind of repeatedly and we learn how to produce these, the cost of producing one unit will go down. So the 200th ocean alkalinity enhancement plant will be cheaper for the same scale as the first. So we can quite credibly say that. We also know that very often technologies become more energy efficient with time. And I think that those are two of the key indicators that we have to keep in mind. And then we also know that the energy system or or the economic system in which a technology functions will also change. So I mean I hardly dare say it, but I think that many of our economies are still decarbonizing or on a trajectory to low carbon manufacturing. So these are all the kinds of things that influence how these technologies will behave and perform. And therefore it is so important that we finally bring that future-looking aspect much more to the foreground. Because otherwise you'd be comparing technologies on a as per today basis, but that's not when they'll operate. They'll operate in 20 to 30 years from now. So you want to analyze them as if we have made that transition already. And that's where our framework starts to give a really good starting point.
Wil (27:24): One thing I'm curious about in that context is if we make the assumption that some of these things, especially the BPMED, are going to be fairly energy intensive. Is it possible, as is in the case with direct air capture, that theoretically we would have enough renewable energy to be able to drive these and make them net negative? But it would turn out to be undesirable to be diverting renewables from other uses such as electrifying the grid. Is that the case? Is it going to be that big an energy hog? And second of all, if it is, is there anything in this framework that helps us to make decisions as to whether this is the optimal use of renewables, assuming that it's not an inexhaustible supply in the future?
Mijndert (28:17): I think that's a very relevant question, right? And I think, taking one step back, I think it's important to highlight that ocean alkalinity enhancement approaches and more widely marine CDR approaches are very different in nature. So as Phil already said, some are nothing more than crushing up rock, basically, and putting that in the sea, either directly at the coast or further offshore. And they are simpler in nature, and potentially, although you still need grinding energy, but require less energy and and less capital inputs. At the other end of the spectrum, there are perhaps like the BPMED case that you alluded to already, Will, is very much an example of an engineered approach where you have a need to install a real chemical plant. It's nothing more or less than that, right? To make the alkalinity that you can then deploy to the ocean. So it is very difficult to say - I mean, it's easy to say which one will probably be the more energy efficient, right? And I think methodologies and frameworks like the one we've developed are very very good at that. Whether…to your question, whether now, certainly now scarce renewable energy should be directed to one purpose or the other, I think people have been looking at that. That's not explicit in our framework, but the results from our framework can very happily be used by people who make such analyses. So then we're talking about abatement cost curves, right? Or marginal abatement curves. Obviously always the lowest hanging fruit is energy efficiency if you look at mitigating carbon, right? So with energy efficiency measures very often you earn money. And it has a very high impact. But the amount that we can do is also not so big and then come in things like renewables and further towards the the end of the abatement curve are our CDR options. I think turning the question around, we are at a stage that if we are serious about meeting two degrees then we can't do without carbon dioxide removal anymore. No matter what some other people are trying to say, but I haven't seen any credible evidence of that. So then rather than saying hey, we should not use electrons for energy hungry CDR but for the electric cars or for electrifying our homes and industries, it's not a matter of that, it's a matter of and and right? So then instead of having this dichotomy between the one or the other, we should probably be planning for how can we do both, because that is what we need if we’re serious about meeting climate targets.
Anna (31:21): I think that's a really, really important point. You're kind of trying to walk a very fine balance, right? With a report that's supposed to drive and facilitate decision making, like you said, yet at the same time, because we need carbon dioxide removal, you I assume are also trying to direct decision makers, whether that's regulators or whether that's innovators or whether that's scientists, to sort of put the finger in the places where the efficiency is not high enough yet, so that it becomes a solution. So I'm curious if you want to say a little bit more about both how you're walking that balance, sort of making assumptions about the future – you talked about that already – but also really facilitating decision making, right? Like what is it that after maybe using the framework or going through the report, let's say, an electrochemical OAE company or researcher can take away and really use in order to refine a system? Where are the areas that you would say decision making is really facilitated.
Mijndert (32:29): I think that what a framework like this one is very good at doing is showing for a number of different scenarios, for a number of different points in time, what are indeed the drivers of a certain performance, right? So what it will do in any case is, these are the extremes, right? It can show which technologies, for instance, will never be net negative. And I don't think there will be so many. But if there were any technologies that will never be net negative, then the framework can show that. And then it's easy, right? Be done with these. At the other end of the spectrum, the framework will be able to point to really clear technologies that have so much potential that you know it's a no-brainer not to pursue them. But most of the technologies will probably be somewhere in the middle. And then it's not about winners versus losers, but indeed pinpointing where the challenges are and where there is potential for improvement and where this improvement should happen. And that is an excellent starting point for directing further research and development. And maybe I'm skipping ahead a little bit, but I think many of the CDR technologies, and that includes OAE, are still kind of in a lab-constrained stage, right? So we've done a lot of tests in a laboratory environment. Maybe you've done a little bit of a bigger test, but very often still in constant artificial conditions, if you will, and not so many field trials. And I think having the results of of these kind of assessment frameworks and the questions and the, let's say, the hotspots or pain points that they highlight will allow you to do a lot of pilot testing in the field and exactly focus on on on these elements that you need to confirm or reject to be able to see whether there's more future potential. And I think that's how frameworks like these can also be used very very well.
Anna (34:39): And building on that, in order for that, as you mentioned, to sort of evolve, you need the real world data and you need the real world implementation. Do you have a sense for where we are at currently with respect to the real world data? Do you feel like we're on the tenth kilometer of a marathon? Are we on the first kilometer of a marathon? Like when would you say do we know that we have quote-unquote enough real world data to really say yes, this is now a model that has enough real world data such that you can, to your point, throw something off the table or keep looking into the future?
Phil (35:17) I mean for the technoeconomic assessment, usually that's sort of bolted together with technologies that in a lot of cases we know quite a lot about. I mean BPMED is probably one of those that we know least about or is sort of developing or is what's called an earlier technique technological readiness level. But things like calcination, for instance, heating things up in a kiln, we've been doing that for thousands of years. I mean we know how to do that. So that type of technology data will, particularly for the early TRL technologies, will continue to improve as we develop plants and working systems. I think in terms of the environmental lifecycle assessment, I mean I think a lot has happened over the last five years in terms of our understanding of the environmental implications of ocean alkalinity enhancement. A thing to point out is actually the ocean impacts of OAE are not included in life cycle assessment at the moment because we've just not been able to characterize those impacts. There just hasn't been enough data. I think we're starting to get there, but really we'll need a lot more empirical data on the environmental impacts and particularly at higher trophic levels to be able to make a proper characterization and then start to include it within LCA. I mean I think it's starting to become possible but it'll take a little bit more data.
Anna (36:59):Taking it back a step to the beginning of the conversation, when you talk about the environmental impacts or assessing how perhaps higher trophic levels may be affected, may perhaps even co-benefit or benefit from it, how would you quantify that? We had actually a similar conversation just a couple of days ago on the podcast. It strikes me that the life cycle assessment to your point, from a general understanding, focuses on the net negativity aspect or, do we end up with less carbon in the atmosphere than before? When you talk about the effect on the higher trophic levels, do you talk about it from a carbon perspective or from sort of like a different category? And if so, how do you value that in a life cycle assessment?
Phil (37:44): Yeah, I mean there's a bunch of main impacts that ocean alkalinity enhancement might have on the ocean. One is around the carbonate system, so it's essentially changing the balance of CO2 bicarbonate in the oceans. In doing that, in doing some forms of ocean alkalinity enhancement, you can lower the amount of CO2 in the ocean, which in some cases can be an environmental benefit, especially that of environments that are subject to acidification. If it goes too far though, you might remove too much CO2 from the ocean and that's problematic for photosynthesizers. So that's one sort of angle of the environmental impact. And then the other is around things that are added to the ocean along with the alkalinity. So primarily people are thinking about metals. And that those metals aren't necessarily present in all of the materials that you can do ocean alkalinity enhancement with, but in those that are, we're thinking about things like iron, possibly silicon, and maybe some trace elements too as well. Now those might have impacts across the ecosystem. So it might impact at the bottom of the trophic level or might potentially accumulate in higher trophic levels. But we really don't know because the experimental work really hasn't been done on that. I mean some of the early results seem quite promising in that the effect on the carbonate system isn't as bad as maybe what it could be or the effects seem to be relatively benign. I don't think there's any sort of evidence yet that there's been accumulation of metals in organisms. So I think there's promising signs so far.
Anna (39:43): Mm-hmm. So just to to clarify, I think what I'm struggling with a little bit is – or what I'm keen to to find out – let's say you're doing a life cycle assessment and you have quantified your carbon removal based on the carbonate change in the water, yet there is also an increase in trace metals, which has an effect on the ecosystem health. How are those weighed against each other in a lifecycle assessment? Because they're not the same metric in a way. And maybe the answer is that we just really don't know yet how to do that. But I'm curious if you have a thought on that.
Phil (40:22): Yeah, there's a saying in English if you like sausages you shouldn't visit a sausage factory to see how it's being made. It similarly applies to the LCA, actually, if you like the concept of life cycle assessment, you probably shouldn't dig too far under the hood. Because it makes a bunch of simplifications about the impacts onto a set of what are called impact categories. So one of those impact categories is climate change, but another might be something like marine eutrophication. And what it would do is it would normalize the effect of a chemical onto a scale that might be similar to let's say for eutrophication, it would be similar to the effect of nitrogen. So that not really done actually in LCA at the moment. So if you had add ion to the ocean, it wouldn't be characterized at the moment on that sort of eutrophication scale. But there are other impact categories like acidification as well, so you could potentially look at the carbonate system under that lens. But I think it's still debatable whether these impact categories are completely appropriate anyway for all of the impacts for ocean alpha linting.
Anna (41:45) Super cool. Thank you for elaborating. That's really helpful. I think it's something that certainly I didn't really know how that is done or how that's even considered to be done. So I find that I find that fascinating. I'm gonna follow up on that.
Mijndert (41:59): Maybe one comment to make is that also life cycle assessments are kind of global assessments, right? So they normalize compared to other what we call environmental stressors, but they don't necessarily look at what happens very locally from a factory. That's not what they are designed for, nor is it what they do. So there's a difference between very localized environmental impacts. For instance, you have a chemical plant that's producing PFAS and some of the PFAS is emitted into the adjacent river, right? Those are things that happen. That has a very localized effect on that river, as well as it has a globalized effect because that river will stream into an ocean, right? So LCA is very good at quantifying the effect on kind of global ecosystems, but not meant to, nor is it good at, quantifying the effect on the local ecosystem. So in terms of environmental impacts, ideally there will be complementary studies done there, and under Carbon to Sea, these kinds of studies are done, which is a good thing.
Anna (43:19): We did not ask you to say that.
Mijndert (43:22): I wanted to add it anyway.
Anna (43:23): Thank you.
Wil (43:26): So your framework also looks at geographically explicit labor and capital costs. What does this tell us about where these technologies might make the most sense in terms of deployment and where they may never be competitive?
Phil (43:45): Yeah, I mean it's particularly for something like BPMED. I mean because it's energy electricity hungry, essentially the things like costs are normalized to net removal. So essentially how much CO2 is removed minus how much is maybe emitted in the process. So places that are actually already decarbonized look more favorable than others. So you would say that it's not net negative, but actually in a couple of locations like Norway, for instance, that already has a decarbonized electricity grid, it is net negative in those places. And I think actually this gets on to kind of a bit of a wider point in that you've written about this, Will as well, this idea of mitigation deterrence, the idea that CDR or the presence of CDR might sort of deter us from emissions reduction. But I think that's maybe not quite true for a lot of energy hungry CDR technologies where essentially their feasibility is predicated on a decarbonized energy system. So essentially, countries that sort of invest in decarbonizing their energy system will become attractive places for CDR. I think that's a sort of slightly different way of thinking about it than maybe what we have previously. And I think that's something that this sort of prospective approach is really really helping us demonstrate.
Wil (45:19): Yeah, one thing I wanted to follow up on is in these models we may find places where labor costs are lower, capital costs are lower, the costs of renewables may be lower than in some areas, but it may turn out that there's other reasons, including social reasons for not wanting to optimize in those areas. Maybe it's that again, renewables could be used for eliminating activities that are far more environmentally damaging to local populations, for example, or it may be that labor costs are low in an area, but there's a regulatory environment that we wouldn't be comfortable with in terms of assessing these approaches. How do we take those into account and not just optimize on what's lowest cost in terms of determining where we might want to deploy these things? Or is that beyond what these models contemplate doing?
Phil (46:25): Yeah, I think that's beyond really what technoeconomic assessment and life cycle assessment is really trying to do. I mean they're essentially tools and in some ways kind of blunt instruments that sort of feed into a hopefully richer set of criteria that ultimately decision makers - you hope that that would be the case - that decision makers are reconciling things like the social economics or the social acceptability. And that might sort of come out in the planning system anyway, but it's not necessarily included within the framework.
Wil (47:08): Yeah. I just think, and this is no fault of this framework, I just think it's important that policy makers make sure that they're incorporating these other things and not just optimizing on certain criteria. But I think you're right. It provides some of the grist that they would need.
47:28 - What the Next 5–10 Years May Hold
Anna (47:28): Thank you so much for sharing all these insights. I want to close the conversation out with predicting the future of the future. I'm curious what your take is on sort of the next five to ten years for some of these approaches. And perhaps you can focus on what surprised you most about any of their development with respect of everything you've sort of learned throughout this process.
Mijndert (47:49): Phil and I had a really, really nice chat about that yesterday because of course we received the questions, right? I think again we looked at two extremes. Maybe I'll say the one extreme and then Phil will probably like to share the other extreme. So I think the extreme that came to my mind first was I'd be surprised if everything worked as we hoped. Right? So that for every technology everything would go exactly as we see it in the lab or or in small scale tests, et cetera, et cetera.
Anna (48:22): I'm wondering if the opposite of that is if everything goes as you feared.
Phil (48:27): My view is I'd be surprised if nothing worked and there's gonna be something out there that will in some location work. The question's really does that sort of localized feasibility scale to global feasibility?
Mijndert (48:46): I think anybody who has brought something new to market or to scale will know that things never play out as you had hoped at the very beginning. But luckily humans are also very creative and resilient and capable of overcoming challenges and therefore in many situations we are able to make things work.
Anna (49:06): Awesome. Thank you so much for sharing all these insights and making TEAs and LCAs much more graspable for me anyways. I thought it was super interesting. I think there's definitely a strong message we need it, we need carbon removal to solve some of our problems. And in order to do that, there's lots of areas that still need innovation for this to work out and be net negative. So thank you for highlighting some of those and sharing your thoughts.
Mijndert (49:31): Thanks very much for having us.
Phil (49:34): Thanks, Anna. Thanks, Will.
Anna (49:35): Thank you as always for listening to the episode. If you enjoyed this episode, please leave a comment or review, share it widely, and if you want to suggest a specific topic, feel free to reach out to us through our LinkedIn page or via plansea@carbontosea.org.
