Episode 547 Can Concrete be Carbon Negative?

Brent Constantz is the CEO of Blue Planet, a company that makes limestone aggregate for concrete from demolished concrete and CO2 from industrial flues. It is about 40% carbon dioxide, mineralized and locked out of the atmosphere permanently. Peter Fiekowsky joins us also from Silicon Valley, and Pugwashites Derek Paul, Ellen Judd, Peter Meincke, and Michel Duguay question Constantz, eager to learn how this remarkable concrete is produced. and where it will be used. A large Canadian company, Lafarge, will be building plants to create carbon negative concrete. For the video, audio podcast, transcript, and public comments; https://tosavetheworld.ca/episode-547-can-concrete-be-carbon-negative. Guests:

Brent Constantz

Peter Fiekowsky

Adele Buckley

Derek Paul 


concrete, co2, carbon, carbonate, calcium carbonate, building, world, limestone, flue gas, question, atmosphere, sequester, negative, basalt rock, planet, aggregate, purified, capture, calcium


Peter Fiekowsky, Adele Buckley, Ellen Judd, Brent Constantz, Derek Paul, Metta Spencer


        Brent Constantz, the CEO of Blue Planet, a company that produces carbon negative concrete, explains that most of the carbon on Earth is in the lithosphere, mostly in the form of limestone. He says that there is almost no purified CO2 on Earth, and that most carbon exists as carbonate or bicarbonate. He compares the amount of CO2 in the atmosphere, which is about 830 Gigatons, to the amount in the lithosphere, which is about 100 million Gigatons, most of which is in the form of limestone.

        Constantz says that most approaches to mitigating carbon assume that purified CO2 will be used, but that does not exist in nature and takes energy to create. He explains that a tonne of CO2 is equivalent to about one cubic meter of aragonite, or about 11 cubic meters in dilute carbonate solution, such as in the ocean. In contrast, a tonne of CO2 in the atmosphere occupies about 1.25 million cubic meters.



       Constantz says that 55 Gigatons of rock are mined every year, most of which is limestone, and that the infrastructure to support the collection, preparation, transport, and utilization of that rock is already in place. He adds that about 40% of all concrete infrastructure in the world is paid for by governments, which gives governments an opportunity to mitigate large amounts of carbon dioxide on a regular basis with the same dollars they’re already spending.

       Constantz suggests that the approach to mitigating carbon should involve converting dilute CO2 to carbonate, which is what happens to most of Earth’s carbon when it enters the ocean from the atmosphere and ends up in the skeletal remains of marine organisms as calcium carbonate skeletons and eventually becomes limestone. He explains that the molecular weight of calcium carbonate is about 100, and the molecular weight of CO2 is 44, so if a tonne of limestone is in front of him, he has 440 kilograms of CO2 that is now permanently sequestered in the crystal and stayed as carbonate.

       Blue Planet makes synthetic limestone from CO2 from a nearby flue, mixed with demolished concrete and other materials, to create pellets that become the aggregate in concrete. The company has a new contract with Lafarge to make concrete plants using their technology all over Canada and North America.

       Constantz asserts that carbon lifecycle analysis has been performed on their process, and they are monitoring the electrical power usage of every piece of equipment in the whole process. The CarbonStar rating system, funded by the Canadian government and implemented by the Canadian Standards Association, is used to measure the quality of the carbon load of concrete. Blue Planet’s concrete has a carbon footprint of negative 700 pounds per yard, and Microsoft has a corporate directive to be carbon neutral. Constantz explains that Blue Planet’s carbon-negative concrete is also the cheapest way to attain a carbon-neutral building, and it’s the cheapest way to sequester carbon.

       When asked about the National Academy of Sciences and the Japanese government’s efforts in carbon-negative concrete, Constantz suggests that government entities like the Department of Energy can be helpful, but there is an ingrained paradigm that assumes businesses will be built around government subsidies. Constantz believes that climate change is too big for government and would like to see private companies drive the innovation needed to address climate change.

       The Los Medanos Energy Center, owned by Calpine Corporation, is the largest producer of electrical power via natural gas in North America and has a fleet of about 86 natural gas-fired power plants. Constantz and Adele Buckley discuss the issue of CO2 purification and liquification, and how it has been challenging due to the impracticality of the parasitic load of purifying the gas. Blue Planet’s method involves taking a thermodynamic downhill pathway and letting CO2 form carbonate, which is transported in bicarbonate pipelines.

        Derek Paul asks Constantz about the timescale over which the concrete absorbs the full amount of carbon dioxide, and he responds that once the concrete is made, it undergoes the regular carbonation process that any concrete would undergo. But the absorption process in the manufacturing takes about half a second. Paul also asks about the possibility of using Blue Planet’s carbon capture technology in tall buildings, and Constantz explains that lightweight concrete is used in tall buildings, and that they make lightweight aggregate to achieve this.

        Buckley expresses concern over the “carbon negative” label of Blue Planet’s concrete, stating that it implies that CO2 is being taken directly out of the air, which is not the case. Constantz responds that the CO2 comes from natural gas-fired power plants, and that his company has patents on running air directly through the same absorber. They take about half the CO2 out in about half a second.

        Metta Spencer asks about Blue Planet’s sources of calcium for the concrete. Blue Planet doesn’t get CO2 out of the concrete but gets calcium, which is their source of alkalinity. Spencer mentions that other guests have mentioned a shortage of calcium but Constantz insists that it’s not a concern as it is one of the most abundant elements on the planet. They conclude by discussing Blue Planet’s third-party verifications, and Constantz explains that they have hundreds of verifications of what they do, including independent engineering reports for investors and a lifecycle analysis on their website.

       Blue Planet hopes to create planet near ports because transporting rock to ports is cheaper when compared to land-based transportation methods. Adele Buckley requests more detailed analysis of the carbon negative concrete process, but by then Constantz and Fiekowsky have both left the meeting and cannot provide this clarification. Blue Planet systems’ website is suggested as a source of information. Carbon Engineering is another company that uses a similar process but sells the captured carbon to oil companies.

       The group discusses the impact of carbon-negative concrete on reducing carbon emissions and its ability to bring global warming to under 1.5 degrees Celsius by 2050. However, Derek Paul questions the arithmetic of the claim and asks for proof. Adele Buckley agrees that while it is a beneficial process, it alone cannot reduce carbon emissions to the desired levels. Derek Paul believes that the claim assumes that Blue Planet can capture 14 times more CO2 than the cement industry produces, which is unlikely. Spencer will ask Fiekowsky to clarify this claim, which seems implausible.


Metta- Regarding the claim that if 16% of aggregate were synthetic limestone (which is equivalent to 4 Gt CO2 per year, or about 105 Gt CO2 by 2050) then we could keep global warming to under 1.5 Celsius.  Here are the numbers for you: Total aggregate consumption now is about 55 Gt / year. 16% of that comes to 8.8 Gt limestone. 44% of limestone weight is CO2; thus just under 4 Gt CO2 / year would be reduced / removed. Multiply that by 27 years and you get 105 Gt CO2 removed.  105 Gt CO2 removed is proportional to 13 ppm CO2 in the atmosphere (there are roughly 8 Gt CO2 per ppm in the atmosphere. That would reduce the peak CO2 level in 2050 from 460 ppm to 447 ppm Is that enough reduction to keep warming below 1.5C? That depends on how quickly we reduce emissions and how quickly we increase CDR, especially ocean iron fertilization.   In any case, 105 Gt CO2 is a lot. Three years of emissions and 10% of the total excess CO2 in the air.  Peter

Adele-  Great questions. All are quite easily answered. 1. Building plants: The first one is in operation already, scaling up now in the San Francisco area. I think their target is 200,000 tons of CO2 this year. Last I heard, there are one or two more plants getting started in other countries (maybe including Canada) this year. Permitting is the hard part, and makes construction take about 2-5 years. The slow items are: Permitting, raising capital, improving the technology, and training people.  2. Pushing the change: Several organizations: 1) US and Canadian governments call for using low-carbon concrete when possible–that depends on building plants quickly. The cost of the aggregate rock is not an issue. Most times it will be competitive with existing suppliers. Even when it’s 2X more expensive, that only increases typical project costs by 0.5%.  2) Cement companies-most of the major ones are already partnering with Blue Planet to integrate the technology.  3. What if the flue gas from the power plant is out of sync with the Blue Planet plant? You have it right, and backwards. The limestone plant will run continuously to maximize use of capital equipment. The power plant output changes widely during the day and night–because of solar, wind, and changing loads. Blue Planet will have tanks to store the carbonate fluid during times of high output (evenings) for use at night, for example, when electrical production is low.  4. Will this delay the natural gas power plant closing down? Probably not. There is no payment for the CO2 in the exhaust. The power plant is already more expensive to run than solar and wind–so it’s just a matter of building out the solar, wind, and batteries needed–getting the capital and projects built. The price signal is already there.  5. Is this a “knock-out” solution? Yes and no. I recommend you read my book, “Climate Restoration: The only future that will sustain the human race” for details. The knock-out solution is ocean fertilization. That is exactly what nature does to produce ice ages, except rather than blowing iron-rich dust randomly across the ocean to fertilize it, the dust is mixed by ship at the optimal concentration, best time, location, and formulation. This optimization allows CO2 to be drawn down 1000 times faster than nature does before ice ages.  This will cost less than $1 billion per year, and produce tens of billions of additional fishery revenue.  That’s  our “Plan A”.  Synthetic limestone is “Plan B”, and costs considerably more, but could be scaled up if society decided to actually restore the climate to ensure our survival, and for some unknown reason, Plan A fails.  I recommend that you folks put ocean restoration (ocean iron fertilization) at the top of your list. It’s natural, safe, cheap, and could restore CO2 levels by 2050, or even 2040, if that were desired.  Peter

You can do 100%, or even 200% or rock–by creating limestone that coastal cities would use to raise themselves as sea-level rises. It would cost a bit–but only the tiniest fraction of what we’re already spending inefficiently on health care.  If nature can make trillions of tons of limestone, certainly we can too.



This is a machine-generated transcript that may contain errors. Do not cite it without checking for yourself by watching the video and catching any obvious errors.

Metta Spencer  00:00

Hi, I’m metta Spencer. Today we’re going to talk about concrete again. And I’m happy to say that some of my dearest and most wonderful friends in the world are with me. And so we’re going to talk about a very special kind of concrete, which is carbon negative, big time carbon negative. And the special excitement that I’m feeling it has to do with the fact that the CEO of a company that is producing this wonderful concrete, Brent Constantz, is going to be with us. And let us ask him quite a few questions. Because, you know, we’re now doing a series with the Pugwash group, the Canadian Pugwashites, who are very interested in trying to persuade the Canadian government to do good things for climate. And one of the things that we want to do is recommend that all concrete use by the infrastructure that the government pays for should be carbon negative. So we have to get quite confident that what we’re recommending is possible, and Brent Constantz about a year ago in a conversation with me, assured me that he is producing big time carbon negative concrete. And it’s enough so that if, according to their website, if something like 16% of the aggregate used in concrete around the world were using blue planet’s concrete, we would have a storage to sequester enough carbon to keep the world’s carbon emissions or heat increase below 1.5 degrees centigrade. That is one heck of a claim. So good morning, Brent Constantz. And I want to introduce briefly the other people who are joining us. And I’ll tell you, they’re all members of the Canadian Pugwash group. Michel Duguay is an engineering professor retired from the Laval University. Peter Meincke is also a scientist, a physicist. He was the the president of the University of Prince Edward Island recently in his career. Peter Fiekowsky is a friend of yours, I think by now, and is friend of mine, I’m happy to say also by now. He has an engineer himself by background and very much interested in solving problems having to do with global warming. So his book,  Climate Restoration, is absolutely the best book I’ve read in years. Absolutely. I cannot praise it highly enough. So everybody must go out and read that book. Phyllis Creighton is available here. She is a member of the Canadian Pugwash Group and has been very active in the Anglican Church as well. Adele Buckley is another engineer and physicist. And Ellen Judd is a retired professor of anthropology at the University of Manitoba. All of them are just ready to ask you questions about Blue Planet concrete. So, Brent, give us your own pitch. Tell us what you tell people who ask you “Oh, yeah. Is there such a thing as carbon negative concrete?”

Brent Constantz  03:50

Thanks very much. Yeah, I’d like to start off with just a few aspects of where is all the carbon on the planet anyway? It because it’s surprising often that well educated people don’t always know. If we look at Where’s all the carbon on Earth. There’s about 830 Gigatons of carbon in the whole atmosphere. There’s about 2400 Gigatons of carbon in the entire biosphere, all the rain forests. plankton in the oceans, there’s about 38,000 Giga tons of carbon in the hydrosphere. The oceans, lakes, rivers, ice caps, but there’s about 100 million Gigatons of carbon in the lithosphere mostly in the form of limestone. And, for all intents and purposes on a practical scale most of Earth’s carbon is sitting in the lithosphere in a mineralized state. The other aspect is there’s almost no carbon dioxide in a pure state. On Earth. Even if you go to the methane hydrates in the ocean, they have methane and other gases. For most purposes, the only place you find purified co2 Is it Praxair and their products where it’s been, you know, chemistry labs, places like that, there really isn’t a lot of co2, there’s a dilute co2 in the atmosphere. You had about 400 parts per million, there’s diluted co2 coming out of coal fired power plants at about 100,000 parts per million. But there’s really no co2 purified on Earth. Almost all of the carbon on earth that’s not in some biological molecule exists as carbonate or bicarbonate. And that’s most carbon. So a lot of the fundamental approaches to mitigating carbon or managing carbon, assume that we’re going to be working with purified co2, which is actually a very rare substance. It doesn’t really exist. Where it even dilutes the diluted co2, you know, usually with nitrogen in the atmosphere, you know, is a very, very small fraction of all the co2 of all the carbon on Earth. So, I’d like to start off there with that understanding also, when we look at what that looks like, if we take a ton of co2, and we asked what does that translate to? Well, if you think of mother of pearl, you know, it’s the calcium carbonate mineral aragonite. It occupies about one cubic meter. You know, one, once one tonne of co2 is equivalent to about one cubic meter of aragonite or mother of pearl. It’s one tonne of co2 is equivalent to about 23 meters in a gas form as a purified gas, but as a dilute carbonate solution, like the ocean for example, a tonne of co2 is is closer to about 11 cubic meters. So it’s a very manageable form of co2. To put it in contrast, in the atmosphere, a tonne of co2 occupies about 1.2 5 million cubic meters. And so when you look at all the approaches to address carbon management, you start to see really quickly then all the approaches being taken today involve purification of co2 from a dilute gaseous source to get a purified form and in a purified form, it can be liquefied and managed the way that we see all these hubs developing like for enhanced oil recovery. So what we’re doing is we’re forming carbonate. We don’t purify co2 at any point in our process. We simply take dilute co2, and we convert it to carbonate which is what happens to most of Earth’s carbon when it enters the ocean from the atmosphere and ends up in the skeletal remains of marine organisms as calcium carbonate skeletons and eventually become limestone, like the Great White Cliffs of Dover or the Great Barrier Reef. So, fundamentally, the molecular weight of calcium carbonates about 100 and the molecular weight of co2 is 44. So if I have a ton of limestone, calcium carbonate limestone in front of me, I’ve got 440 kilograms of co2 that’s now permanently sequestered in the crystal and stayed as carbonate. Now, if you look at the mass material flow on the planet, other than water, the largest mass material flow today is rock. They’re about 55 Gigatons of rock mined every year. And all the infrastructure to support the collection, preparation, transport, and utilization of that rock is already in place. And it’s been in place for 100 years.

Metta Spencer  10:18

That’s what they use as, as the ingredients for cement it as well as the aggregate, right?


Correct. The limestone itself is one of the one of the ingredients, if you will, that’s centered with other things to make Portland cement, which is the binding phase of concrete. There’s about three or 4 billion tons of cement, made that way every year. And it produces about three or 4 billion tons of co2. By contrast, like I was saying, there’s over 50 billion tons of rock mined every year. And most of it is used in concrete, not all of it, some of it’s used in road base and asphalt and other purposes. But what’s important about it is the 55 Gigatons of rock that’s mined every year. Most of it is limestone. So there are other rocks that are mined like granites, etc. that do not contain any carbon, or much. But limestone is about 71% of all the rock that’s mined. And the reasons for that it’s softer, it’s easier to mine. It’s also more useful in concrete generally, because it is more stable in the alkaline character of the Portland cement. So we already have a system in place that’s been operational since for a century where we’re taking material that is 44% co2. And we’re using it in in the building materials, we have all the infrastructure to move it around, and we have money to pay for it. And it’s not just rich countries that have the money to pay for it. We’re pouring concrete in the poorest countries of the world. And about 40% of all the all the infrastructure of concrete in the world is actually paid for by governments. So it gives government this incredible lever to mitigate massive amounts of carbon dioxide on a regular basis with the same dollars they’re already spending.

Metta Spencer  12:54

Okay, now your transition is, instead of using limestone as quarried, you’re going to make the limestone and you’re going to use it, you’re going to make it from co2 from a nearby flue or someplace like that. And you’re going to mix that with that co2 With demolished concrete, and some other kinds of secret material, which I don’t know. And that’s where you’re gonna get these little pellets that become the aggregate in concrete, right?

Brent Constantz  13:33

Yeah, generally, I might rephrase things a little bit, but that’s it. The let me back up a little bit. So almost all limestone on Earth is the skeletal remains of marine organisms. So the White Cliffs of Dover is almost completely a coccolithophore, which is a plant then photosynthesizes. The Great Barrier Reef is primarily the skeletal remains of another plant, a calcified green algae that collects in the corals. And the corals themselves are calcium carbonate. So all those reactions happen with carbonate.

Metta Spencer  14:21

So Calcium plus carbonate gives you a calcium carbonate, and from the flue gas you are able to create this synthetic limestone, where nobody else can do it. Right?

Brent Constantz  14:38

Well, it’s hard enough for us to get it done. If someone else can get it done. I admire them. It’s been a lot of work figuring all this out. But precipitating calcium carbonate. There’s nothing new about that that’s been around forever. There’s calcium carbonate in milkshakes and paint and paper all over the place. Consolidating into hard rock that can be used as aggregate. And let me back up a little. Concrete is about 80% aggregate and only about 20% cement. And a big portion of that aggregate is what we call sand or a fine aggregate. And another big portion of it is gravel or a coarse aggregate that’s graded very specifically by size and other things. So the value is in the rock itself, the combination of the sand and gravel in the cement gives you a structural concrete. I say that because, you know, precipitated calcium carbonate is a very common substance, but it doesn’t have the market potential, like rock does to go out and sequester billions of tons of co2. But our basic processes are akin to native biomineralization processes. So my only point in making that point is that we’re not purifying co2, which takes a lot of energy or trying to transport it around and high pressure pipelines, which is what most of the world governments think is going to solve climate change. And we don’t do any of that.

Metta Spencer  16:32

Okay, now what you do is quite wonderful. And I know that you’re doing it because Canada has already major concrete company, Lafarge. Maybe Lafarge and Holcim are sort of twins or connected somehow. They have a new contract with you to make concrete plants using your technology all over Canada and North America. I wanted to invite one — I did try to invite some of the Lafarge executives to be with us today and tell us about your plans. But they couldn’t make it; it’s apparently a holiday. And so I want to know, because we’ve had a number of shows about concrete the last several months, and with people who were in the concrete business or experts teaching in universities about concrete, and mostly they never heard of you at all, but I’d tell them a little bit. And they basically look kind of agnostic about well, they say I haven’t seen the numbers. I don’t know whether they’re really doing something that’s carbon negative or not, it would be very amazing, and so on. But nobody really is sure. And we want to be sure, especially since on one of our shows, one of the guests was quite critical and said she didn’t think that there was any such thing as carbon negative concrete. So you got to prove to us that what you do is really carbon negative. And I think my Pugwash guests will have have questions about that. How do we know that what you’re doing is absolutely concrete, negative carbon negative?

Brent Constantz  18:33

Just like everyone else in this area, you know, we perform carbon lifecycle analysis on our process. So, you know, at our plant up on San Francisco Bay, we are monitoring the electrical power usage of every piece of equipment in the whole process. You know, we know that carbon balance coming in the flue gas from the Calpine power plant, and to get a full carbon analysis, generally in this area, and this is true, not just concrete, but anytime you’re capturing carbon, for example, we refer to it as a parasitic load. That means, how much co2 You’re you’re creating in order to capture a certain amount of co2. And to be honest, most of the processes that the world governments are proposing to spend billions of dollars on are not carbon negative, actually produce more co2 than actually sequester. And let me give you a good example since we’re talking about Canada. In Canada, somebody who I mentored 20 years ago, started a company that buys co2 from Air Liquide or Praxair. And they go out to concrete plants, which is where you put sand, gravel, cement and water together. And they have these ones that they squirt this 100% purified liquefied co2 into. And it’s that 100% purified liquefied co2 itself has its own carbon footprint, because it took a lot of energy to purify it and liquefied and pressurize it and transport it and all that. And about 1% of the concrete actually gets carbonate, it turns to carbonate in that process. And it’s been touted as a major breakthrough in concrete. That is, you know, a very important pathway to capture carbon and stored in concrete. Well, in reality, in reality, most of it just escapes into the atmosphere.

Metta Spencer  21:10

Well, I can believe you and most of the conversations we’ve had with these academics and concrete builders have been of the sort where they basically are giving good ideas for how to use less concrete in construction, so there’s less emissions from the cement, or how we should just be happy, if we can have what they would call lower carbon concrete, they do not even aspire to talking about carbon negative concrete. So the the remarkable thing is that you do. Now I know that last year, you told me to check out something that is a Canadian system of measuring the quality of the carbon load or whatever of concrete. It was called CarbonStar rating system or something. And that is apparently a quite a rigorous kind of testing system. Yeah. I think you mentioned that you had you done that or you’ve been measured, can you can you say what this Canadian outfit thinks about you?

Brent Constantz  22:31

Well, it I guess it uncovers the the deception a little bit by putting numbers down on it. But yeah, the CarbonStar rating system was funded by the Canadian government and implemented by the Canadian Standards Association. And it’s in use now. For example, at San Francisco International Airport where we’ve poured concrete, if you even want to bid on the concrete there, you need to have a CarbonStar rating of 200. So let me explain what that is. A normal yard of concrete has a carbon footprint after considering the parasitic load and everything, a carbon footprint of 600 pounds. And that’s mostly because it has 600 pounds of cement in it. If you even want to bid on the concrete at San Francisco Airport, it has to have a carbon star rating of 200 pounds. They have a reach goal of a carbon star rating of zero, and then a regenerative goal of a carbon star rating of negative 200 pounds. Now in a typical yard of Blue Planet concrete we just use the normal amount of Portland cement so that that gives us 600 pounds, but we use 1200 pounds of sand. 44% of that is co2; 1800 pounds of gravel 44% of that is co2. So that’s about 3000 pounds of coarse and fine aggregate. And know 44% of that’s around 1200  – 1300 pounds. So we’re putting 1200 pounds of co2 into that same yard of concrete which erases the 600 pounds from the cement and now we have negative 700 pounds per yard in the concrete. Okay, so the kind of impact that has is, we’re working with a number of the social media companies that are building large campuses here in Silicon Valley. And some of them are owned by Microsoft. And Microsoft has a corporate directive to be carbon neutral, not just operationally carbon neutral in there. on things, but in terms of the embodied carbon as well. And so they’re trying to find ways to be carbon neutral. And when you’re building a large campus, there’s so much steel and glass and other things. It’s really impossible with most building materials today. And then the concrete itself is usually a huge problem. In this case, the concrete solves the whole problem, and more. What’s really interesting about it is like you alluded to earlier, structural engineers and architects are trained in the very beginning to minimize material as much as possible. So we had a case for one of the buildings, the engineering team came in and said, Look, we were able to cut all the concrete in half. And I said, is that so you could have a better carbon footprint? They said, Yeah, of course, isn’t that great? And I said, No, you should have doubled the concrete because with no carbon negative concrete, the more concrete you usem the more co2 you sequester. And when we look at the profile, you know, a lot of those decisions are pure economic decisions, right. And if say, I’m LinkedIn, and I have to have a carbon neutral, 200,000 square foot campus, I’m looking at all my alternatives. And, you know, they look at buying offsets, which are really expensive, and we’re not sure what a good idea that is, anyway, in most cases. They could build a dedicated solar farm. And all those options are really expensive. We can literally charge 50% extra for the concrete. And it would only increase the per square foot price of the building by less than half a percent.

Metta Spencer  26:57

Wait a minute, you’re claiming that your your concrete is actually economical too?  I figured people would be paying a premium to get your wonderful concrete. But tell me, is it competitive with standard concrete in price as a means of sequestering co2?

Brent Constantz  27:21

Most people think about $75 a tonne, you know, is where they’d like to get in terms of sequestering co2. No one’s near that right now. Right? I mean, Microsoft’s paying over $1,000 a ton on the voluntary market for co2 sequestration. But the point I was trying to make was that even if we were to charge 50% over the market price, it would increase the price of the building by less than half a percent per square foot, which compared to the other alternatives to make a carbon neutral building is almost nothing. You know, to buy offsets, you’re probably talking 10 – 15% of the cost of the construction, you know, to build a solar farm again, you’re up in that range. So, you know, it’s by far the cheapest way for someone to attain a carbon neutral building. It’s also just the cheapest way to sequester, you know, capture co2. You know, if you look at what’s out there now, every approach to capture co2 is trying to capture it and purify it and liquefy it. So it can be transported in pipelines and injected, like a waste underground to get some sort of government subsidy. And the problem with that whole approach, building businesses based on government subsidies, you know, aside from the fact that there’s only five operating carbon sequestration projects on the planet other than enhanced oil recovery, injecting purified co2 into saline reservoirs. And they’re all fraught with problems. Yet, this is what all the governments of the world are focused on – money.

Metta Spencer  29:17

I’m going to invite the Pugwashites  because I am monopolizing your time. And I’m sure that there are various people who have questions of their own. So if anybody wants to ask a question. Yes. Here’s Michel. Great.

Derek Paul  29:38

I have been tremendously impressed by your presentation. That was on one of the Metta’s videos. The first question that comes to my mind is: Would it make sense to get the National Academy of Sciences on our side? The NHS is very powerful. Congress and the US Senate will follow usually the recommendations of the National Academy of Sciences. Secondly, when you talk about governments in the world, I got the impression from looking it up in Google, that the Japanese government has been doing some good stuff in carbon negative. concrete. So these are my two questions.

Brent Constantz  30:28

I’ll answer the second first. So one of our significant investors is Mitsubishi Corporation. And we are working with them. In members in the University of Tokyo, where there’s a strong concrete group, yeah, Japan has a lot going on there. We have quarterly steering committee meetings with our our people at Mitsubishi. You know, one thing we found is that government entities, like the Department of Energy can be very helpful. We’re building a second or third phase of our plant in San Francisco. We applied for a Department of Energy loan guarantee for a $260 million project that we’re building there. And we just passed what’s called phase one, and now we have to do phase two, and there’s a lot of help there. But there’s also this ingrained paradigm that we’re gonna address climate change with subsidies coming from the government. And then we’re going to pay to eradicate all the co2, it creates these structures, supported by the National Academy of Sciences,  that assume that we’re going to build businesses around government subsidies. If you just sit down and do the simple numbers on the back of an envelope, you can see that only a few rich countries really have that possibility and the possibility of doing anything significant in terms of climate change, or our de minimis. And, yeah, I’d love to get the National Academy of Sciences and evolve, but if you look at the reports they produce, I guess I’ll go on to the next question, but I’ll just say this is too big for government.

Metta Spencer  32:47

I like that, okay. Yeah. Who else has a question? No doubt.

Adele Buckley  32:55

Excuse me, I have a couple of questions. I guess. You’re right. This is a very cool plan. And you get the carbon dioxide from there. Is it part of a carbon capture project or is it straight from the flue gas?

Brent Constantz  33:15

So we’re at the Los Medanos Energy Center, which is owned by Calpine Corporation, which is the largest producer of electrical power via natural gas in North America, they also are the largest hydro Thermal Generator in the world. But Calpine was founded by Pete Cartwright with the intention to eradicate coal by replacing it with natural gas. And Pete actually built the Fukushima power plant and has a lot of history and power. So he was a real visionary. This was back in the early 90s, that he he did that.  Calpine has a fleet of about 86 natural gas fired power plants. And we take their flue gas and, you know, strip the co2 out of it. But it powers most of the city and county of San Francisco with their power. What’s interesting about it is they also just address your question of had a DOE grant to do co2 purification, and liquification and put it in pipelines and take it into the California Central Valley to be injected underground. And the project completely stopped because they couldn’t get pipeline routes. They couldn’t find secure places to inject the co2 and just the parasitic load of purifying this co2 is totally impractical. And that’s been the case over and over and over and over and over again. But you’re gonna see these co2 sequestration projects in here, increasing that IRAC, I think is going to put over $200 billion into, into these co2 hubs. But the positive side of it is, and that’s why I was talking about where’s the carbon and bicarbonate, because we’re building hubs ourselves, but we’re not transporting purified co2 around. We’re just taking a thermodynamic downhill pathway and letting the co2 form carbonate the same way 99% of the carbon on earth does. And we’re piping it around in bicarbonate pipelines, which can be simple water pipelines, not highly pressurized pipes with compression stations, you know, which is really just part of the oil industry?

Adele Buckley  35:57

Well, I’m not sure you’re answering my question. I wanted to know, where’s the co2’s coming from?

Brent Constantz  36:05

Its natural gas fired power plant, okay.

Adele Buckley  36:07

But it’s not coming from the air. Or I mean, you know, hugely indirectly, it, you take it from a natural gas plant, which it is and you somehow or other, you do a bit of extraction bit of co2 before it goes into the concrete. So that’s, that’s all fine. It’s just a matter of I worried about the labeled carbon negative. Certainly, you’re sucking in carbon. But carbon negative seems to imply some help, and you’re taking it out of the atmosphere. That’s not really the case. So

Brent Constantz  36:52

Actually, if you look at the way a natural gas fired power plant works, is it combust the natural gas, and it draws in about 90% air through the system. But it’s an interesting, arbitrary distinction that you see out there these days. If if a molecule of co2 is inside the flue gas pipe, people ask the question you’re asking, if it’s half a millimeter outside the flue gas pipe, and in the atmosphere, than they say what you’re saying that therefore that’s good, you’re taking it out of the atmosphere. Anyone who works on isotopes can tell you that what’s in the atmosphere is is a lot of it is anthropogenic, it’s anthropogenic co2 that’s going into the atmosphere right now. And we’re never gonna get anywhere if we try and make these distinctions about whether it’s a millimeter outside of flue gas pipe or a millimeter inside the flue gas pipe to call it negative. That’s never going to help save the world for our children. It’s the same co2 and co2 molecules doesn’t  know whether it —  How about this? If I go to a bristle cone pine that’s 3000 years old, and I chop it down and burn it. Is that carbon negatives? Because it’s a fossil, it is 3000 years old.

Adele Buckley  38:19

I think it should be made more clear that on the carbon negative aspect to me, you’re not taking it directly out of the air, which, would mostly people would assume that would be what you’re doing.

Brent Constantz  38:33

So when a millisecond later when it’s outside in the atmosphere, am I taking it out of the air?

Adele Buckley  38:43

Sorry, my second question, but I think I’ll let someone else talk. Well get rid of my cough.

Metta Spencer  38:49

Okay.  Yes. Hi, Derek. I didn’t introduce you. Derek Paul, a retired physics professor, University of Toronto. just joined us.

Brent Constantz  39:05

Nice to meet you. We’ve heard a lot of people at a Toronto.

Derek Paul  39:08

I have several questions about this amazing concrete, which I’m very interested in. From a scientific point of view. What is the timescale over which your concrete absorbs the full amount, the maximum it can have the carbon dioxide. How long does it take practically in practice?

Brent Constantz  39:31

Well, once it’s concrete, it would just undergo the regular carbonation process that any concrete we’d go under, which is a few percent per decade at the most, but our absorption process takes about a half a second. A large, large packed column that was an absorption solution that goes from the top to the bottom and then the flue gas goes from the bottom to the top and as they pass each other, the co2 is absorbed into the solution.       Yes.

Derek Paul  40:06

So, so that by the time anybody handles this concrete, it’s, it’s fully developed with the most co2 It’s going to have, it’s not still sucking it in?

Brent Constantz  40:20

Well, it is a little bit, but it’s just like regular concrete. They carbonate, you know, from the atmosphere as well. But, you know, just to put in perspective,  we’re getting,  80% of the mass of the concrete is the sand and gravel. And if that’s all limestone, 44% of that is co2. So in 4000 pounds of concrete, you know, we’re sequestering over 1000 tons of pounds of co2, the amount of carbonation, you get over, say, 50 years from the atmosphere would be maybe 20 pounds? Yeah.

Derek Paul  41:12

That’s the kind of understanding I wanted to have. And have you any experience with building tall buildings with this concrete?

Brent Constantz  41:24

Yeah. So you might already know this. But in tall buildings, every floor is concrete, as a fire prevention measure. And for that application, it is what’s called lightweight concrete. Regular concrete is, 150 pounds per cubic foot, whereas lightweight is under 100 pounds per cubic foot. And that’s obtained by using lightweight aggregates, since aggregate is 59 – 80% of the mass of the concrete. So we do, one of the types of aggregate we manufacture is lightweight aggregate to get lightweight, concrete. In fact our ports at San Francisco Airport on the terminal are all lightweight concrete, because you know, the walkways, you go out to the gates at the airport. Those are all elevated concrete slabs. And so we use lightweight concrete in those applications.

Adele Buckley  42:24

Well, I see that you can replicate your plant lots of different places in the world, providing it’s beside a source of co2. Of course, there’s plenty of sources of co2, but the implication by negative co2 is, I think you might be taking it out of the atmosphere. But if we, if we would do the ideal thing, we would stop burning natural gas, and there wouldn’t be any co2 to go into your process, because you need it that way. But there’s the I mean, they’re they’re clearly a lot of applications for your process.

Brent Constantz  43:06

 But let me just interrupt for a second and say, we do have several patents on running air directly through the same absorber. And we take about half the co2 out in about half a second. So even compared to these conventional air capture systems that are being developed, since we’re not trying to make purified co2, which they all are, and that’s why they’re interacting with the oil industry to take their co2 and use it for enhanced oil recovery to get the low carbon fuel standard credit. We can just run air right through our absorber and take it from 400 PPM down to 190 ppm. And we do that all the time. But the least practical way to capture carbon out of the atmosphere is to do direct air capture. In fact, it’s been published all over the place just in this last week. But most of us have known this for a long time. Direct ocean capture is 100 times more efficient than direct air capture if you really wanted to. The atmospheric co2 is in equilibrium with the ocean. So if you pull the carbonate out of the ocean, it’s about 100 times more efficient than direct air capture. Direct air capture takes 1.2 5 million cubic meters per ton, you know, with a fraction of that. I mean, it’s almost like Monty Python, what they’re trying to do.

Adele Buckley  44:38

Direct air capture seems like the worst possible way of dealing with it because it’s just so little amount captured compared to the enormous amount of expense. So not not a good idea. But my other main question is, has, has anyone else looked at your figures, your entire system from start to finish and said, Yes, we agree with you and we’re a third party, we have no interest in your business, as a third party verified what you have done.

Brent Constantz  45:16

I think there’s probably hundreds of groups that have done that,  for  independent engineering reports for investors. And,  it’s being in Canada, we got a $500,000 grant from the Alberta government about six years ago. And we, you know, the DoD loan guarantee program is pretty rigorous thing and all our investors, whether you, or Mitsubishi Corporation, Chevron Corporation, Salter.  Salter is the largest manufacturer of these absorbers in the world. They’re our largest single share, dollar shareholder, we have weekly meetings with their teams of experts. But yeah, there’s been hundreds of verifications of what we do.

Adele Buckley  46:11

Well, I think it would be good if you would publish some statements from them. I mean, not if your actual information is proprietary, then, of course, that has to stay where it is, but if someone who is not not connected to you would probably show their their findings that are positive, I would, I would feel a lot more confident about us, you doing your process all over anywhere.

Brent Constantz  46:44

That’s what’s so great about what we’re doing. All we have to do is do it. You know, we don’t have to get the blessing of any outside body of experts that never produce anything, or do things like direrct air  capture. We don’t even care. You know, we’re just saving the world here. We’re not trying to get a blessing.

Derek Paul  47:09

He’ll get it anyway. You tried to give a blessing. Really.

Metta Spencer  47:18

I want to get Adele’s blessing, but I’m thinking: what is normally used for this kind of proof is a lifecycle analysis, isn’t it? And so probably somebody’s done a lifecycle assessment of a blue planet concrete and ask him to send me a copy. And I’ll make Adele happy.

Brent Constantz  47:43

I think there’s an LCA on our website even. Now, we have a whole department that does LCS, they’re experts in the area.

Metta Spencer  47:54

I want to ask you about where are you going to get your concrete? Because obviously, you lucked out with the idea that you don’t have to count in the demolished concrete that you use. You don’t have to count that against the cost of making your concrete because it was made of sidewalks that were poured 100 years ago or something. And so this is like finding a rock that already you didn’t put the co2 in in the stuff and so you’re not responsible for counting it against your manufacturing process. And I think that once you don’t have any more demolished concrete that you can use, and you have to find some other sources. I’m not sure it’ll be the carbon negative, will it? Because you’ll have to count whatever you use as a source. So tell me, isn’t that the case that the reason your carbon negative is that you don’t have to count the carbon that was generated by the people who made the demolished concrete that is your feedstock?

Brent Constantz  49:23

You don’t you don’t have to count it anyway. Because it’s old. Yeah, actually, most of the time, we don’t use demolished concrete but we don’t get co2 out of the concrete; we get calcium. That’s our source of calcium. So okay, so that has nothing to do. We use basalt rock, we use slag. use fly ash. We’re really interested in the basalt rock because it’s very common, and it’s very abundant. In fact, one of our largest investors is Knife River, which is one of the largest aggregate producers in North America and all their quarries are in basalt rock. We found that to be a really good — we call it a geo-mass. It’s a source of alkalinity. You need two moles of alkalinity to neutralize every carbonic acid  because the reaction starts with co2 plus water makes H2 CO3, which is carbonic acid and if you want to get to carbonate you need two moles of alkalinity like an oxide, for example, like current calcium oxide. And any form of that,  like basalt rock, there are matric rocks, like in Oman and California. But there’s abundant supplies of geo-mass all over the world.

Metta Spencer  50:40

Okay, but as I understand it, there’s a shortage of calcium. If you if you’ve used up all of the demolished concrete, where are you going to get all the calcium you’re going to need next?

Brent Constantz  50:55

Calcium is one of the most abundant elements on the planet actually, there’s not a shortage of it. In you know, both calcium and magnesium make carbonates, fact, the most common rock carbonate rock out there is not like what we call limestone. It’s dolomite, which is a calcium magnesium carbonate, and it’s more stable. And it’s been used as an aggregate over a century. But there’s definitely not a shortage of calcium.

Metta Spencer  51:25

Yeah, that’s a source, but you’re not gonna go out and and chip off a few pieces of the White Cliffs of Dover to use.

Brent Constantz  51:34

You wouldn’t do that. That’s a carbonate. If you did that, that would release co2. Right? So if you go to common rocks  that are full of calcium, like we’re doing, like from the basalt quarries and other places like that, there’s no limit on that.

Metta Spencer  51:51

Okay, well, all I know is that some of the other guests on my show in the past have said, calcium is scarce, there are not many places, you’re gonna get it. So I don’t —

Brent Constantz  52:03

Maybe they’re on another planet. Just go on your Google and say source: What is the what are the five most common elements on Earth?

Adele Buckley  52:21

Okay,  and it’s in a form that you can put directly into your use for it.

Brent Constantz  52:29

If you look on our website, that’s our reformation process. Step you’ll see on the website. I’m sorry, I’ve got a group that just showed up. And I got to sign off. Okay.

Adele Buckley  52:41

One more question. You can locate in many different places. But  there must be some places where in the globe where you can’t locate, where they still want to build with concrete.

Brent Constantz  52:57

Yeah, ports. Ports are where we want to locate. That’s where all the transportation is. It’s been built up the infrastructure the world’s already built up around ports.

Adele Buckley  53:12

Yes, but the rock in the ports obviously has to be transported there.

Brent Constantz  53:18

Right. When you’re on water, it’s quite different than being on rail or truck.

Adele Buckley  53:24

Yeah, that’s cheaper.

Brent Constantz  53:27

Okay, nice. I really appreciate your time. Thank you.

Adele Buckley  53:30

Thank you. Thank you. Thanks so much. Bye.

Metta Spencer  53:35

Okay, friends. Now, if you have any further thoughts that you want to share with each other, we can put another couple of minutes into this.

Adele Buckley  53:45

Where where is a link to some of the more detailed analysis that shows why this is carbon negative and why it is economically sound or why the process works without revealing of course, anything proprietary? I’d like to read about it, but I don’t know where to find it. Okay,  Peter Fiekowsky, do you have a good answer to that? How can we make Adele happy?

Peter Fiekowsky  54:17

Well, I don’t know how to make Adele happy. Maybe I’ll take you out for a milkshake, with a little bit of calcium carbonate in it. But Blue Planet systems.com is the website. So just Google blue planet? And I believe they have the LCA there. I think it’s important useful to ask what is the question we need to answer. One of them is: Should Canada make stronger carbon negative concrete standards? There are other other fundamental questions that we need to advise on?

Metta Spencer  55:01

Already, the Canadian government, even before we started this project, had enacted some sort of new regulations saying that from now on, any projects that are funded by the Canadian government must be what they call “low carbon concrete.” They didn’t say anything about carbon negative, because nobody is very much aware of it. But of course, low carbon concrete is a lot better than standard. But it’s not on the same scale, whatever, as carbon negative, because that’s especially this kind of level of carbon negativity, I think. So now, I’m still worried about making Adele happy. She really wants some hard numbers. One of the people who probably isn’t with us, but would have been is Peter Wadham, who is in Turin, Italy. He teaches at the best polytechnical university in Italy, although his actual his home university is Cambridge University. And Peter Fiekowsky had introduced Brent Constantz to him. And he now gives lectures, he’s giving a course on global warming and how to solve it. And he talks about the the blue planet concrete in his course. And he said that the university is building some new building using blue planet concrete. And he thinks that he could find some documents that the university produced when assessing blue planet in order before they signed the contract. So he was going to bring some numbers with him. And the reason he hasn’t brought numbers is, he’s not here because I gave him the wrong URL, probably, I don’t know. But if he does have these numbers in his own file, I’ll get them from him and I’ll send them to Adele.

Peter Fiekowsky  57:04

If I may suggest to Adele, go to the blue planet website and download their LCA, the lifetime life cycle, life cycle assessment, Adele and Metta, the Canadian company Carbon Engineering — are you familiar with them?  They are a direct air capture company.

Metta Spencer  57:27

David Keith’s outfit, right?

Peter Fiekowsky  57:29

Yeah. And so they use almost the same process, except they take co2 from the air or from a exhaust stream, and they turn it into into calcium carbonate. But rather than selling the calcium carbonate, they then heat up the calcium carbonate (they call it Calfining), but they heat up the calcium carbonate to release the co2 again,and then they sell the co2. But it’s that heating up of the calcium carbonate that’s very expensive, and takes phenomenal amounts of energy. And so the point is that this is a process that’s been refined. It’s nothing new, there’s nothing secret about it. The chemistry is fundamentally very simple. Brent has 100 patents or so on it, because as he said, the hard part isn’t isn’t  precipitating the calcium. The chemistry is all well understood and published. The hard part that Brent brought in is, how do you make it into a useful product that can be sold? Carbon engineering makes it into a useful product that the oil companies use to extract more oil. And they make a lot of money doing that. A lot of us aren’t crazy about producing more oil. But be that as it may, as I said, Blue Planet uses  the calcium carbonate and sells it as a product for different construction.

Ellen Judd  59:16

Apart from the National Academy of Science in the US, we should be able to locate something a candidate that can do something similar, that isn’t necessarily a government department because you’re looking for something independent, I don’t think NSF would do that. It might fund scientists to do it. But you could look at, say, the Royal Society or some of the other academies that sometimes show up and do this kind of study.

Metta Spencer  59:46

And they claim if they if the world shifted 16% of the aggregate that is used each year to using Blue Planet aggregate, we would be able to reduce the global warming to under 1.5 degrees Centigrade increase by 2050. Now that there’s nobody else in the world that will even try to make that claim. This is extraordinary.

Derek Paul  1:00:25

So it’s a claim for which we have never been presented with the arithmetic. And I think the arithmetic is very likely in error, very likely.

Metta Spencer  1:00:38

So tell me what we need to do to get the arithmetic. There are 440 kilograms of co2 in eery metric tonne of their concrete. They of course, are producing a little bit of co2 in the manufacturing and the transportation of the stuff and all that. So when you take account of that, then their concrete is 40% co2.

Derek Paul  1:01:14

Metta, just look at it this way for one moment. The industry is only producing something like seven, maybe 8% of all the emissions and the concrete could reabsorb. Not only that, but all of the rest of the emissions is what they’re claiming in this claim. And I don’t see how that could be possible. That’s what I say it’s up to them – display the arithmetic. So you sent that out as a written statement, and I presume you got it from,

Metta Spencer  1:01:48

I got it from their website. Yeah.

Derek Paul  1:01:52

It kind of makes me think it’s a very big exaggeration,

Metta Spencer  1:01:58

Then I don’t know where to go from here. I will ask Peter Fiekowsky.  I don’t know who else knows the the numbers, I will ask Peter Wadhams, I’m not sure where to go to satisfy exactly.  What I want to do is make sure you’re —

Derek Paul  1:02:19

If they’re making that claim, it’s they that have to do it. When you’re a scientist, you have to prove your result when you publish it. And then a claim which I don’t think is quite correct,

Metta Spencer  1:02:32

It has to do with the stupendous amount of concrete that is being used in the world.

Adele Buckley  1:02:38

Well, I think you’re sort of right and sort of not right. Well, one of the things that we really want is to get the readout, reduced fossil fuel use reduced, presumably, preferably to zero. And as long as we’re burning fossil fuels, that produces a source of co2, which they can use in the concrete and everybody benefits in some way. But none of this takes any of the existing co2 out of the air.

Metta Spencer  1:03:11

It’s not a matter of taking it out of the air. It’s taking it out of the total amount that is being produced.

Adele Buckley  1:03:26

Of course, you’re right. But but it’s not going to take us back to to the 1.5 degree warming, until somehow there is a way out either cooling the planet by doing engineering, God forbid, or do something, which is different than burning fossil fuels, and taking the carbon dioxide out of the flue in order to help build the concrete, which is quite wonderful. And I think I think it’s beneficial by the sound of it. But but we going on to claim that it’s going to return us to 1.5 degrees C of warming is excessive, and there’s nothing nowhere to back that up.

Derek Paul  1:04:11

The claim that I read, and I read it very carefully, assumes that not only is their concrete carbon negative, but they can suck out amounts of co2 equal to 14 times what the concrete and concrete and cement industry produce. And I don’t think that’s correct. I don’t think it can be the figures don’t add up, but they should produce the proof of what they say. And it’s it’s it’s a pity because this is  a great project that we will be hearing about. I’m 100% in favor, but I just don’t believe that claim.

Adele Buckley  1:04:57

Each individual project is sequestering co2. And I think that we have come to believe that is true. They’re actually making carbon negative concrete, if you want to call it that, because it gets co2 that, was going to go into the atmosphere and it goes into the concrete. So great. We believe that. But they sort of scale up,  saying if we had how many plants all over the place, we would save the world. That that is something I cannot, don’t  believe. It’s okay to just do per plant. It’s an excellent activity. But saying, This is how we’re going to save the world. If we only did a lot of plants, that’s the part that really troubles me at this point.

Derek Paul  1:05:52

Thanks very much for the invitation, because it was really great listening to this guy. There.

Adele Buckley  1:06:00

Okay, thank you very much. Bye, bye. Okay


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