Podcast Episode 1.60

Concrete, steel and plastics: Paths to a greener industrial sector

with Rebecca Dell

Each year, we produce about 30 billion tonnes of concrete globally. That’s nearly 10,000 pounds, or more than 2 entire cars-worth of concrete, per person, per year.  We produce enough steel to build more than 2700 Empire State Buildings annually.  We produce more than 100 pounds of plastic per person, each year. And with all of this material production, we also produce a lot of greenhouse gas emissions.

Nearly one-third of global GHG emissions come from industry, with steel, concrete, and chemical manufacturing (i.e. plastics) being the largest contributors. These industries are tough to decarbonize because they require performing chemical reactions at high temperatures, not easily achieved through electrification, and because they emit greenhouse gasses as a by-product.

Climate Now sat down with Dr. Rebecca Dell of the ClimateWorks Foundation, the largest philanthropic program in the world dedicated to reducing and eliminating greenhouse gas emissions that come from the material economy. Dr. Dell shares how these industries are approaching decarbonization, and what kind of technological, policy and market innovations will be needed to reduce the industrial carbon footprint.


Rebecca Dell
Industry Program Director, ClimateWorks Foundation


Rebecca Dell

Industry Program Director, ClimateWorks Foundation

Dr. Rebecca Dell is the Program Director, Industry at ClimateWorks Foundation. Previously, she worked at the U.S. Department of Energy in the Obama administration, where she coordinated implementation of President Obama’s Climate Action Plan and was a lead analyst and author of the U.S. Quadrennial Energy Review. Before her federal service, Rebecca was a scientist at the Scripps Institution of Oceanography, studying the interaction between the ocean and land-based ice sheets like those in Greenland and Antarctica. She has a Ph.D. in climate science from MIT.

Hosted By:

James Lawler
Climate Now Host


James Lawler

Climate Now Host
James Lawler is the founder of Climate Now. James started Climate Now as a way to learn about climate change and our energy system. Climate Now’s mission is to distill and communicate the science of our changing climate, the technologies that could help us avoid a climate crisis, and the economic and policy pathways to achieve net zero emissions globally. James is also the founder of Osmosis Films, a creative studio.

[00:00:00] James Lawler: You are listening to Climate Now. I’m James Lawler. Before we get started today, I’d like to invite everyone to subscribe to the Climate Now newsletter, which you can do at climatenow.com. Subscribers to our newsletter are the first to receive new episodes of the podcast, as well as deep-dive articles in our Systems Thinking series, where we pull in all of the information that we’ve been gathering from our experts to give you a comprehensive overview of key topics related to the energy transition, such as decarbonizing road transportation and the energy efficiency resource. 

[00:00:39] James Lawler: Creating industrial products like steel, concrete, and plastics require energy intensive processes. Traditionally, producing that energy has involved burning fossil fuels. And a lot of them. Because of this, industrial emissions have been considered a hard to abate sector, but what are the opportunities to reduce industrial emissions, and what is being done today? 

[00:01:01] James Lawler: We’re pleased to be joined today by Dr. Rebecca Dell for a conversation on decarbonizing the industrial sector. Dr. Dell is the industry program director at ClimateWorks Foundation. She also worked with the U.S. Department of Energy (DOE) during the Obama Administration, where she coordinated implementation of the Presidential Climate Action Plan. She has a PhD in Climate Science from MIT. Dr. Dell, thanks so much for joining us today. 

[00:01:25] Rebecca Dell: Thanks so much for inviting me. 

[00:01:26] James Lawler: So, tell us first about your background. How did you get to where you are today in your career?

[00:01:31] James Lawler: What led you here?

[00:01:32] Rebecca Dell: You know, people come to environmental work from a lot of different directions. I did not expect to end up here. I went into climate science because I really liked physics, and I thought that the physics problems of the ocean and atmosphere sounded interesting. But, as you might imagine, being a climate scientist in our current moment, it’s something of a radicalizing experience.

[00:01:58] Rebecca Dell: I spent almost 10 years between my PhD and working as a scientist. Slowly over that time, I realized that the thing that was holding back our action on climate change was not the quality of the science, and so I might be able to have a bigger impact on what was clearly the most important problem of my generation by getting involved in government and public policy.

[00:02:27] Rebecca Dell: So, that’s when I went to work for the U.S. Department of Energy (DOE). I was there for four years, and then left at the end of the Obama Administration, and since then I’ve been working for various NGOs and foundations in the climate space, and I ended up working in industry. 

[00:02:43] James Lawler: What was it like in the DOE? What was your role there and what did you get into there?

[00:02:49] Rebecca Dell: I found DOE to be a really exciting place to work. I was in the policy office, and this was a time of an enormous amount of interest from the secretary, and even from President Obama, in trying to figure out what can we do to move further, faster on climate change? When I left the government, I took some time to take a step back and survey the landscape.

[00:03:15] Rebecca Dell: The big question I was trying to answer was, what are we not doing? What is the missing piece here? And I realized that if you look globally, the industrial sector is responsible for a quarter of greenhouse gas emissions. If you add in the greenhouse gas emissions from generating all the electricity that’s being consumed by industrial facilities, that goes from a quarter up to comfortably more than a third, or uncomfortably more than a third of all greenhouse gas emissions. 

[00:03:47] Rebecca Dell: So, this is a huge chunk. This is one of our top-tier climate problems: what do we do about the industrial sector? At the time that I was kind of going through this process, back in 2017, I was looking around and there were so few people in this space, hardly any money, hardly any policy ideas, hardly any corporate initiatives, there was nothing happening. So I was like, okay, that looks like a place where I can really make a difference.

[00:04:17] James Lawler: So, what brought you to ClimateWorks, and what is ClimateWorks, where you are today?

[00:04:22] Rebecca Dell: We’re a grant making organization that is exclusively focused on climate change. My particular focus is in the industrial sector, which covers manufacturing, construction, mining, waste processing. Basically, when we talk about industry in the climate context, we’re talking about stuff and not energy—the physical material of the economy. That’s a lot of stuff. There are a lot of different activities and whole, you know, sectors of the economy that are involved in making stuff or moving stuff around, but there’s actually a very short list of activities that are responsible for most of the greenhouse gas emissions, and those are making the basic materials that we make other things out of. Things like steel, cement and concrete, fertilizer, plastic. The kind of basic materials that everything else is made out of, that’s what’s going to drive those greenhouse gas emissions.

[00:05:28] Rebecca Dell: So, I said about a quarter of greenhouse gas emissions are directly emitted by the industrial sector. Two-thirds of that come from the industries I just listed

[00:05:38] James Lawler: Of the three that you mentioned as the three big contributors to industrial emissions, and again, you mentioned petrochemicals, concrete and cement, and steel.

[00:05:47] James Lawler: Maybe we’ll start with petrochemicals. What are the emissions from the petrochemical industry? How do they break down? What does that sector look like?

[00:05:56] Rebecca Dell: So, if you look at the total life cycle emissions of the petrochemical industry, we’re talking about more than 3 billion tons of CO2 equivalent emissions per year from that sector. To give you a frame of comparison, the total greenhouse gas emissions from the entire U.S. economy are like five and a half billion tons. It’s a huge amount. It’s half of the emissions of the entire U.S. economy for this one sector. Most of those emissions are in the form of CO2, but also there’s a large amount of emissions that come out as methane, and as other non-CO2 greenhouse gasses. Of that more than 3 billion tons, we’re talking about probably two-thirds of it, so about 2 billion tons come in the production of the chemicals, and then the one-third comes in the use or disposal of the chemicals.

[00:06:54] James Lawler: I wanted to clarify something with you, and you could maybe shed some light on this. Our understanding is that plastics are created through hydrocarbon byproducts from fossil fuel consumption for energy.

[00:07:06] James Lawler: So, one of the things we’ve been wondering is, do you see the plastics industry changing as a result of a move toward more renewable energy sources, in that there won’t be necessarily that same flow of hydrocarbon by-product from the production of fossil fuels for energy?

[00:07:23] Rebecca Dell: Yeah. That’s a great question, and I think this is actually an area that I think is really under studied, and that might have big implications for the way that these industries evolve in the future, because for the whole history of the petrochemical industry, it has kind of developed in tandem with the motor fuels and refining industries.

[00:07:47] Rebecca Dell: So, most petrochemical facilities you’ll find adjacent to refining facilities, and they’re exchanging products and byproducts all the time. That being said, that’s a relationship that is common and widespread in today’s industry, but there’s no necessary relationship there. So, if you look around the world, there are giant chemical facilities spread all over the world, and what they use as their primary feedstock and primary energy source just depends on what’s locally available.

[00:08:23] Rebecca Dell: In the United States, our chemical industry is very, very heavily dependent on methane and what are called natural gas liquids, and those are not refining byproducts, those are things that sort of raw materials directly from the ground into the chemical facility, and we do that because those things are widely and cheaply available in the United States, because of our natural resources, and the choices that we’ve made about drilling for those natural resources.

[00:08:55] Rebecca Dell: In Europe, they don’t have the same natural resources, so their chemical industry is very dependent on refinery byproducts. So, those crude oil extracted products, but things that typically come to them after the motor fuels have been taken out. In China, they have relatively modest domestic resources of both gas and petroleum, so they do a lot of their chemical synthesis, just starting from coal. They go from coal to chemicals, which is much more greenhouse gas intensive, but that’s the natural resource that they have, and so that’s the way they prefer to do it. 

[00:09:34] Rebecca Dell: So, just because the refineries go away or the demand for motor fuel goes away, we should not expect that the chemical industry will somehow go away. Quite the opposite.

[00:09:42] James Lawler: To what degree is recycled materials as a feedstock to the petrochemical industry currently developed?

[00:09:49] Rebecca Dell: The framework that I tend to use to think about this is, when we’re making petrochemicals, you need two things. You need both energy and you need feedstocks. Because in the feedstock, particularly in the case of plastic, the products themselves are made out of carbon.

[00:10:05] Rebecca Dell: So, you need carbon atoms from somewhere, and that’s your feedstock. Today, we use fossil fuels for both the energy and the feedstock, and when we talk about de-carbonization, people have a lot of ideas for both clean feedstocks and clean energy, and actually most of the solutions that you’ll find only are trying to solve one of those two problems.

[00:10:26] Rebecca Dell: It’s very unusual to find an approach that’s trying to solve both, so recycling is probably our best avenue, at least from a technical perspective, for clean feedstocks. Because you say, okay, we already have this massive plastic in the world, and that has all the carbon atoms we need, and they’re already in a similar chemical form to the outputs that we want because they’re already plastic. We should be able to process that relatively easily and cheaply into new chemical products. Sure, in theory. In practice, we do a very terrible job of doing this.

[00:11:04] Rebecca Dell: Just yesterday, a new report came out from Beyond Plastics, where they found that the United States Environmental Protection Agency, the EPA, estimates that between 8 and 9 percent of plastic in the United States is recycled. That’s not an inspiring number. That between 92 and 93 percent of plastic at the end of its life is not recycled. And this report that just came out yesterday found that actually the EPA overestimated because they were using old numbers and old methodologies, and our rate of recycling in the United States is actually going down, not up.

[00:11:47] Rebecca Dell: So, the real number is somewhere between 5 and 6 percent. So, you know, there’s a really strong technical argument there, but as a matter of social and economic systems, we have not been able to make it happen so far. 

[00:12:00] James Lawler: Why is that? I mean, to your point earlier, we should know a way to process plastic which is already near to the final form as the things we want to make from it. It potentially could even be easier than spending so much energy to drill these other materials, so why are we so bad at this? Why is it not more of a widely used feedstock in the first place? 

[00:12:21] Rebecca Dell: There’s a lot of reasons. The proximate reason is that the waste stream of plastic that we generate is very low-value. So, if you just look at what is in a recycling bin, and what ends up getting recycled, it is a mixture of lots of different types of plastic, of products that include plastic and other materials that are laminated together in ways that are very hard to separate. It includes trash and other things, and with the systems that we have in place today, trying to separate out the valuable material and recycle it, that separation process is more expensive than just drilling for more oil, or more gas. 

[00:13:10] Rebecca Dell: So, you say, why is that? Why are our waste streams so low-value? There’s a lot of reasons, but one of them, a really important one, is that the people who manufacture and market the products have no responsibility whatsoever for what happens to those products at the end of their life. In a rational system, you might say, okay, every bottle in the entire country, it should be made out of the same plastic and you should just use the same formulation for every single bottle,

[00:13:41] Rebecca Dell: When you collect the bottles, it’s very easy to separate the bottles from the not-bottles, and then you’ll just have a pure waste stream of one type of plastic. But for any individual manufacturer, there’s no rule you have to follow, so just make it out of whatever’s convenient to you. The products are designed in a way that makes them very hard to recycle.

[00:14:04] James Lawler: You mentioned in a, I think this was in a tweet you wrote, that the chemical industry is responsible for 8% of U.S. energy consumption. That industry makes plastics, fertilizer, and other essential products and has lots of cool technologies, but no clear climate vision. What are the different opportunities that are most likely to reduce the chemical industry’s emissions?

[00:14:25] Rebecca Dell: Yeah, I stand by that assessment. While the chemical industry, there’s lots of interesting things happening, I don’t think anybody has sort of a clear line of sight to what a climate-safe chemical industry is going to look like. There’s a lot of open questions there, but I find it helpful, as I said, to use the framework of clean feedstocks and clean energy.

[00:14:51] Rebecca Dell: So, when we talk about clean feedstocks, we talked about recycling already. Other options include things like getting your carbon from biomass. That’s certainly an option, but you pretty quickly start running into constraints on how much biomass you can actually source sustainably. That might be an important solution for part of the problem, but that’s not going to be the broad stroke solution.

[00:15:18] Rebecca Dell: There’s also a set of people and companies who are increasingly thinking about, is there a way that we can just get the carbon out of the CO2 that’s already in the atmosphere? So, turn CO2 into chemicals. You can do that. It requires an extraordinary amount of energy, but I think there are some interesting startup companies and that kind of thing that are trying to commercialize CO2 to chemicals, but my rough back-of-the-envelope calculation is that if the whole chemical industry today used CO2 and electricity to get its carbo, instead of what it’s currently doing, the amount of electricity that would be required would be basically 50% of all the electricity that we have on Earth. We could do it, but whoa, that’s a lot of clean electricity we’re going to require.

[00:16:14] Rebecca Dell: Then on the clean energy side, you know, we can always use clean electricity and we should, and then I think we should also take really seriously options to be more material-efficient. Everybody knows that you should be energy efficient, you know, don’t waste energy, but I think we’re still as a society in a very early stage of our conversation about material efficiency.

[00:16:40] Rebecca Dell: Can we deliver the same products and services, the same level of comfort to people, but just use fewer materials to do it? 

[00:16:48] James Lawler: I think that’s such an interesting point. Oftentimes, this conversation is localized around megawatts, and around how much energy, you know, but really what we should be asking about is the services, that’s what we’re trying to solve for.

[00:17:01] James Lawler: We’re trying to solve for the results of this energy, not the quantity of energy itself, and that’s where we often miss, I think, in this.

[00:17:08] Rebecca Dell: Absolutely. We were talking about recycling, so if we can use secondary materials instead of new material, that’s great, but also, these material industries, their products are very inexpensive.

[00:17:22] Rebecca Dell: The cost of the actual plastic resin that is in your typical bottle of water that you might’ve bought for 1 or 2 dollars is like 0.2 pennies. When you’re selling a product for a thousand times more than the cost of the materials that it contains, there’s not a strong incentive for you to use those materials efficiently, and usually we don’t.

[00:17:50] James Lawler: Really interesting. So, I want to move to the second industry that we want to talk about with you, which is the cement and concrete industry. I wonder if you could first give us an overview. How is concrete produced? What’s producing the CO2? What part of the process? 

[00:18:06] Rebecca Dell: This is your classic example of the effects of scale.

[00:18:11] Rebecca Dell: Concrete has three main ingredients. It has sand and small rocks, which we call aggregates, water, and cement. Cement is basically the glue that holds the sand and small rocks together, and this gives you a material that has some really very, very convenient properties. Why do we love concrete so much? Because it’s a rock that you can pour.

[00:18:41] Rebecca Dell: We like rocks. They’re very strong. They can hold up things, but actually carving rocks is very hard. With concrete, you just pour it and then it turns into a rock, and so it’s very, very easy to make it. It’s cheap, and it’s easy to make it in any shape that you want and in any location that you want. It’s so much better than masonry, which is just rocks, so we use it in fantastic quantities. 

[00:19:11] Rebecca Dell: Total global concrete consumption is somewhere between 30 and 35 billion tons per year, which is an insane number, and basically what that corresponds to is about 10,000 pounds of concrete per human per year, for every single human being on the entire planet.

[00:19:36] Rebecca Dell: It’s so, so, so much, and the greenhouse gas emissions are really driven by the cement. So, it’s not that the cement is so greenhouse gas intensive itself, but it’s just that we make billions of tons of it. We talked about the plastics and chemical industry, the petrochemical industry being responsible for about 3 billion tons of CO2 per year. For the cement industry, it’s like 4 billion tons

[00:20:02] James Lawler: You mentioned in a recent op-ed for the New York Times that using low-CO2 concrete could reduce concrete CO2 emissions by 20% or more. This includes reducing the cement in concrete, replacing it with additives like CO2 or fly ash, which is a by-product of the fossil fuel combustion process. We’ve heard of a couple of companies that sell CO2 to concrete makers. CEMEX has created low and net-zero carbon concrete and cement by recycling concrete and reforesting quarries, and also using alternative additives. There are other companies. Can you talk about sort of what these various companies are doing, and pros and cons of their methodologies?

[00:20:42] Rebecca Dell: So, basically the main ingredient in traditional cements is something called clinker, and making the clinker is what generates the overwhelming majority of the greenhouse gas emissions, and so in order to get to zero, in order to actually zero out our emissions from the cement industry, we are going to have to figure out ways to make clinker without emitting greenhouse gasses. Eventually, we’re going to have to get there. However, before we do that, we have enormous opportunities to make both low clinker cements. So, using other ingredients that have lower greenhouse gas intensity than clinker to make our cement, and also, to make low cement concretes.

[00:21:34] Rebecca Dell: And those are things that in many cases, there aren’t any technical barriers. There are techniques for doing this that have already been used in many applications for decades in different countries around the world. We know that they work, but they’re just not widely, and certainly not universally, adopted.

[00:21:54] Rebecca Dell: Often, you can save money by doing those things, because the clinker is not just the most CO2 intensive, it’s also the most energy intensive ingredient. You mentioned, for example, fly ash, which is a by-product of coal combustion. So, burning coal. You can blend that into your cement and replace a significant portion of your clinker, and reduce CO2 emissions that way.

[00:22:21] Rebecca Dell: There are other of these types of additives that are widely available. Some of them are industrial byproducts, some of them are natural materials, and some of them are processed materials, but they’re materials whose processing doesn’t emit the same kind of greenhouse gasses. In my opinion, one of the most interesting and exciting opportunities here is LC3, which stands for Limestone Calcined Clay Cement.

[00:22:45] Rebecca Dell: This is a cement that has only 50% clinker, where traditional cement is 95% clinker, and the other 50% is made up with limestone and calcined clay, so these are other types of rocks that are widely available, and that require much less processing than traditional cement, and so emit much less greenhouse gas than traditional cement.

[00:23:10] Rebecca Dell: If you blend them together in the right way, you basically get a drop-in substitute for our traditional cement. You can use it in exactly the same way, but since you’ve reduced the amount of clinker by almost half, you’ve you reduce the total greenhouse gas emissions by 30 to 40 percent. 

[00:23:28] James Lawler: So why is this not more widely used?

[00:23:31] Rebecca Dell: The short answer is that there is no incentive in most places. 

[00:23:37] James Lawler: Is it more expensive?

[00:23:39] Rebecca Dell: Nope. It’s not. In most places, it will be cheaper.

[00:23:43] James Lawler: Isn’t that an incentive. If it’s cheaper? 

[00:23:45] Rebecca Dell: Well, for private construction, you know, people building buildings in the United States, the cost of the cement is less than 0.5 percent of the cost of a construction project on average.

[00:24:01] Rebecca Dell: So, if somebody comes to you and says, hey, I’ve got a great idea, I can get your cement bill from 0.4 percent of your budget down to 0.3 percent of your budget. You might be like, I think I might get more payback if I focused my attention elsewhere. It’s hard to get people to use a material efficiently when it’s that cheap. You know, the first customers are in emerging economies where they are building new cement kilns and building new cement facilities.

[00:24:35] Rebecca Dell: Their attitude is, well, why not? Why don’t we just start with the cheaper thing? So, there are a couple of factories currently under construction. One in Columbia, and the other one I think is in India, but I have a lot of optimism that this is something that could be taken up very widely.

[00:24:52] James Lawler: So, what gives you that optimism? I mean, you described a picture that sounded pretty bleak on the face of it, in that we consume and we’re using a huge quantity of concrete, and the incentive to make any kind of process change, which would reduce the emissions profile of the materials and sort of the process itself, is almost non-existent.

[00:25:13] Rebecca Dell: I think, the fact that it is available and cheaper. That is helpful. I don’t think that’s enough to get widespread adoption tomorrow, but I think in order with LC3, or with any of the options that we have, moving further, faster is going to require policy and market interventions. So, one of the things that I spend a lot of my time working on is a set of policies that we call Buy Clean.

[00:25:44] Rebecca Dell: We were previously talking about private construction, but actually an enormous amount of cement and concrete goes into public construction. In the United States, almost half of all cement goes into construction projects that are paid for with taxpayer dollars. So, one really great way for us to get started in moving down the emissions curve here is for the government to say, if you want us to buy your cement, it has to be produced in a responsible way. 

[00:26:18] James Lawler: Are there any other opportunities to reduce emissions from the concrete industry?

[00:26:25] Rebecca Dell: The big one also is, again, material efficiency. We are just astonishingly wasteful in the way that we use cement and concrete, and this is not something that is somehow specific to high-income countries. We think that actually the use efficiency of cement is probably lower in low-income countries than it is in high-income countries. 

[00:26:47] James Lawler: What does a more efficient use of concrete look like? 

[00:26:50] Rebecca Dell: People have done studies where they look at buildings and infrastructure and things like that, and they say, how much structural material do you think you need to make sure that not just will this structure stand up, but you have all of the appropriate safety margins, and you are fully in compliance with all of the appropriate building codes. How much do you actually need in terms of structural material? And they frequently find that there is between 50 and 100 percent more structural material than is required to comply with our extremely safety protective building codes.

[00:27:29] Rebecca Dell: They just use twice as much concrete as they need. 

[00:27:33] James Lawler: Why is that? 

[00:27:34] Rebecca Dell: It all goes back to how cheap concrete is. So, for example, let’s say you have a certain size that you need for the foundation of a structural pillar in a building. So, the engineer for the building will specify, this is how big the foundation needs to be.

[00:27:53] Rebecca Dell: Then the contractor shows up, and the contractor has the option of digging a very precise hole. that’s exactly to the specifications of the engineer, and probably building a mold that would go down into that hole that you would pour the concrete into to get exactly the thing, or Option B, the contractor can just dig a big hole that is bigger than what the engineer specified, and just fill the whole hole with concrete. Option B requires a lot less labor, but a lot more concrete. But labor is more expensive than concrete, so they often go with Option B. So, in my opinion, at least, we are going to have to have much more targeted requirements in addition to carbon pricing if we decide to do that.

[00:28:40] James Lawler: Interesting. And you’re developing policy recommendations now on what that targeted structure would look like?

[00:28:47] Rebecca Dell: Yeah. We already talked about one example, which is Buy Clean regulations, and that’s a situation where it’s not really a price mechanism. What’s happening is the biggest customer, the government, is saying, we simply won’t buy your product unless you meet our standards. It has nothing to do with the price. You’re just not eligible unless you meet the standards.

[00:29:10] James Lawler: Where are you with the development of that?

[00:29:13] James Lawler: Several U.S. states have adopted Buy Clean laws. This is our first year with compliance obligations in California, which is the first state to have this law, that will start this summer. President Biden also instructed the federal government to start developing these policies back in December, and part of the federal government, what’s called the general services administration, is the part of the federal government that is responsible for overseeing the federal real estate portfolio. So, all the buildings that the federal government owns, which is like, that’s a lot of buildings. They have just recently announced their first proposed standards for low GHG building materials for federal buildings.

[00:30:03] James Lawler: That’s great. So, I’d love to hit our last sector here. Steel. Steel emits the most greenhouse gasses of the industrial sector. Why is that? 

[00:30:13] Rebecca Dell: I mean, it has a great combination of high CO2 intensity and high volume of production. You’re multiplying two large numbers together, so it’s worth just pausing for a minute to acknowledge that every steel mill on Earth makes more CO2 than steel. In terms of the total mass of its products, it’s a CO2 facility that also makes steel. 

[00:30:41] James Lawler: That’s an incredible frame. 

[00:30:43] Rebecca Dell: When we make aluminum, that number is not two tons of CO2 per ton of steel, it’s 18 tons of CO2 per ton of aluminum. But, we use a lot less aluminum, and so the total global emissions of the aluminum industry are very small compared to the total global emissions of the steel industry.

[00:31:03] Rebecca Dell: On some level, why is steel the highest emitting industry? Because steel is fantastic. Steel is so great. I mean, think about it. It’s strong, it’s stiff, it’s formable, it’s durable. It has a wide variety of valuable thermal and electrical properties. It’s fantastic. We love it. And so we use it for everything. 

[00:31:26] James Lawler: Why is it so emissions intensive in terms of the process of making steel?

[00:31:30] Rebecca Dell: Steel is almost all iron by weight, and iron atoms really, really like to bond with oxygen atoms, and so you have to run that chemical reaction backward in order to get back to metal. That requires a lot of energy, and the way that we supply that energy in almost all cases is by burning coal. So, there you go, 4 billion tons of CO2 per year.

[00:31:57] James Lawler: So, what are the opportunities then to reduce the greenhouse gas emissions in the life cycle of steel?

[00:32:02] Rebecca Dell: There’s a bunch of things we can do. We’ve already talked about material efficiency in the context of other industries. We can and should do that in steel. We should also recognize, however, steel is already the most recycled material on the planet.

[00:32:15] Rebecca Dell: We recycle 85% of steel. We actually do a really good job of collecting steel and reusing it at the end of its life. That’s a real option. We should pursue it. We should also understand, though, it’s not necessarily the low hanging fruit. If you want to make new steel, then you still have to do that chemical reaction where you pull the oxygen and the iron atoms apart.

[00:32:38] Rebecca Dell: There’s a startup company called Boston Metal that is basically trying to use electricity directly to do this. So, basically you take a bunch of this iron oxide, you get it hot enough to melt it, and then you just put an enormous electric field across it, and the electric field is so strong that it just directly pulls apart the iron and the oxygen.

[00:33:03] Rebecca Dell: That’s one option, and that might be a really good option, but it’s what we call a pre-commercial technology. That’s a technology that’s still in development. Another option is, instead of using coal, you could use hydrogen. The most kind of prominent example of this is a project that’s being sponsored by the European Union and the Swedish Government called HYBRIT.

[00:33:26] Rebecca Dell: It’s in Sweden, where they are designing and building a new kind of furnace that will be fed by hydrogen instead of coal. You imagine you’re pulling off these oxygen atoms, you’re giving them a new place to hang out. If coal is carbon, if the oxygen atoms are heading toward the coal, you’re going to get CO2. If the oxygen atoms are heading toward hydrogen, you’re going to get H2O, which is a much less obnoxious gas to have in our atmosphere. Because it’s water. 

[00:33:58] Right.

[00:33:58] Rebecca Dell: In case that wasn’t obvious. 

[00:34:01] James Lawler: ArcelorMittal has announced they’re using this electric arc furnace. What does that mean exactly?

[00:34:07] Rebecca Dell: Sure. This is a thing that we use already in the steel recycling industry. So, an electric arc furnace is a purely electric technology, and it’s something that we use to melt the steel. Basically, what happens is, the current steelmaking technology, which is called a blast furnace, you just put in the iron ore and the coal, and you get melted steel out. The alternative technologies, often either with scrap or with the hydrogen reduction or other technologies, when they’re finished with their processing, you get solid iron, and you need to melt it so that you can control its composition and form it into products.

[00:34:51] Rebecca Dell: The electric arc furnace is, all of these technologies are funneled into the electric arc furnace, which is kind of a core processing stage for your steel, for a lot of different potential ironmaking routes. Companies like ArcelorMittal, they’re very traditional blast furnace companies, so for them it’s a really important step toward the next generation of steelmaking to say, we’re moving away from the traditional blast furnace, we’re opening up the possibilities for all of these different ironmaking routes by investing in both the physical assets, and the company expertise for the electric arc furnace.

[00:35:37] James Lawler: Of these different steel-making technologies, what do you think is most promising? 

[00:35:43] Rebecca Dell: The way that I usually think about it is that the hydrogen route, that’s the one that’s closest to being ready to go. So, I think five years from now, we are going to have hydrogen steel mills that are producing commercial quantities of carbon reduced steel, and people are going to be out there making them into cars and products and everything.

[00:36:08] Rebecca Dell: So, that’s actually pretty close to being ready to go. However, it requires more energy than the electrolysis, Boston Metal-type route.

[00:36:19] Rebecca Dell: These are very, very energy intensive processes. The steel industry globally uses like 5 percent of all energy that’s consumed by humans on Earth. So, if we can get the electrolysis route working soon, that’s going to be even more attractive because you can save so much money on your energy.

[00:36:41] Rebecca Dell: So, I think it’s probably going to end up being a combination of those two, supported by better higher quality recycling, with more material efficiency. 

[00:36:53] James Lawler: That was Dr. Rebecca Dell from ClimateWorks Foundation talking to us about innovations and opportunities to decarbonize the three biggest emitters of the industrial sector: chemicals, concrete, and steel.

[00:37:04] James Lawler: To listen to other episodes, watch our videos, or read our articles, visit climatenow.com. To get in touch with us, please email us at contact@climatenow.com. We hope you’ll join us for our next conversation.

Share podcast: