Making cement -- the most commonly used substance on Earth after water -- is responsible for 8% of global carbon emissions. It generates CO2 both through combustion of fossil fuels & through chemical processes. Sublime Systems thinks it has solved both sides of that equation. I talk with the CEO.
One question I have about this approach that I didn't hear discussed is what is the anticipated split between capital costs, electricity cost and other costs. With this and some other technologies, that's relevant to understanding whether they can be powered directly from intermittent electricity (and tolerate the duty cycle that implies) or need to be paired with batteries (or some other approach). I've seen plenty of discussion of this as a factor for green hydrogen given capital cost of electrolyzers so curious how this potentially compares.
Concrete manufacturing is a continuous process, you don't want to thermally cycle the facility for a variety of reasons including productivity, thermal inertia, undesired intermediary reactions, and thermal fatigue on the machinery. Lime calcination is likewise a continuous process and takes place at 900C (or above). These are not processes you can turn on and off in a week, much less to follow a daily duck curve; they have one or two scheduled shutdowns each year.
They are highly predictable, though, so you can closely match storage capacity and safety factor to daily demand year over year. As such, all manner of mechanical storage (pumped hydro, pressure) enters the frame and not just batteries or yet-not-scaled hydrogen meant to farm tax incentives in thermodynamically sub-optimal ways.
The big industries leverage simple and fool-proof processes that won't be going down regularly service and updates. It is called a stock pile because it is a pile... of stock. A large facility will have large yard full of stockpiles for inputs like aggregate and lime and outputs, but also coal for backup power. You won't find an Ops manager willing to accept a hydrogen backstop when their entire facility can be damaged if some part of a first generation (read untested) supply system breaks down or fails to deliver required power at the required time. And while the regular use requirement minimizes hydrogen's escape problems those problems make it a poor long term reserve storage solution - that backup supply for when things go wrong that piles of coal do so very well.
Thanks Geoff for this detailed answer, but it is answering a different question than I asked. Your explanation makes a lot of sense for why cement production as currently practiced can't/shouldn't be thermally cycled to follow power availability.
However, my question is regarding the proposed alternative cement production process which Sublime Systems is pursuing as described in this podcast. This does not involve high heat (and has several other differences) so different factors, if any, are likely to be at play for whether the process needs to operate continuously.
Also, my reference to hydrogen wasn't a proposal to use it to power cement production (which as you note has several drawbacks). Rather, since Sublime's process involves an electrolyzer (as does hydrogen production), I'm asking about the capital cost of that electrolyzer (and surrounding equipment) as a potential limiting factor on the feasibility of this proposal.
My understanding is that electrolyzers are reported to be well adapted to power intermittency. Another beneficial characteristic is that they can be modular & containerized, so that banks of containerized electrolysers provide redundancy & backup capacity for periodic maintenance & replacement. I suppose that ideally, electrolysers would be located as close as possible to large wind, solar &/or geothermal resources to take full advantage of off-peak power.
I deleted my original reply, because I was out over my skis trying to figure out what they are doing here and how they are going to succeed. There isn't enough information to know much about what they are doing, and while Sublime's Arpa-e grant (https://arpa-e.energy.gov/technologies/projects/electrochemical-synthesis-low-carbon-cement) mentioned off-peak renewable electricity and grid services that's just as likely the available funding pathway as a real story of industrial scale out.
Structurally, if you have a more expensive synthesis route and more expensive CapEx you cannot also bet on lower utilization to make up the difference. Some back of the envelope math puts the OpEx at $500/ton for Lime with $220/ton the delivered incumbent rate - for a final commodity that goes for $75/ton - a lot of work to do!
But it took Form Energy 7 years to explain what they were doing and everything shared by Sublime to date is "early stage startup ambiguous" - as it should be. Their facility *can* produce *up to* 100 tons of concrete each year. Their novel process makes lime, which comprises only 5-20% of that potential mass. They don't report how much they've made. In the few pictures of the facility online it is a very clean setup in a small corner of a large space. For their test samples they'd need about 30 lbs of lime to create the concrete to submit for the tests (3x cube and slump), but there is no reason to gate that recipe and method testing behind the novel feedstock synthesis work - it wouldn't be disingenuous to have commercially sourced the precursors for the test. They planned to have a field test of undetermined scope and scale by the end of this year - meaning they haven't hit that milestone previously. Recycling the working fluid and being clever with the concentration can greatly improve cost and speed of the process - but that's not a thing to talk about yet. As a company this early finds their first customer(s) and makes their first deliveries everything can change.
I wanted more, I want to understand how this is supposed to work; we got a tantalizing outline suitable for a Series A company still trying to figure that out for themselves.
This is such a cool development, literally and figuratively. It seems like Washington-Oregon would be a good place for plants to be established, looking at the combination of surficial basalt, inexpensive renewable energy, water transportation and "cap and invest" CO2 permit expenses that cement producers and consumers (I think) pay in this region. Electrolyzer talent is getting developed here too as work on a hydrogen hub ramps up. A major downstream destination for products from this region happens to be Portland, perhaps making a nice story, in transitioning "Portland cement."
Thank you for sharing! Super interesting podcast. One thing I want to mention - in addition to decarbonizing the actual manufacturing process, with technologies like Sublime, there's also important work to be done by trading our building materials. Cement and concrete can't be entirely replaced, but companies like Biomason, which is replacing cement with biotechnology, and mass timber buildings, like Mjøstårnet in Norway, also have a role to play! The key to the sustainable transition is diversifying!
Nice. Leah seemed believable. I've been intrigued by my hometown folks doing something similar with iron/steel @ https://www.electra.earth/.
As with that, I keep asking... how much of that "cheap renewable electricity" is needed? In some Google searches there are returns with useable #s.
A pound of cement at the factory door sells for all of $0.06/lb. Of that, it seems like fuel cost is about $0.015/lb, less if trash tires are used.
Some #s in a wonky paper by Leah convert to 0.75 kWh/lb cement in the Sublime process. So at $0.04/kWh for those cheap renewables, it's $0.03/lb. Could be less in the right place and time. So an add in the range of $0.015/lb or 20% range. Not bad.
With the effect of the limestone CO2, GHGs fly out the stack at about 1 lb CO2/lb of cement. At the current $200ish+/tonne damage estimates, that's $0.09/lb of cement, which if applied would more than double that wholesale price. This illustrates the frustration mentioned with $0.04/lb available for post-combustion CCS or $0.08/lb for DAC CCS.
That's how I understand the #s. The H2 generated by the electrolyzers is used for some needed thermal heat. There would be other electricity involved with either process. I try not to get to enthralled w/revolutionary "cleantech," and always figured one of the few logical use cases for CCS is cement, but I like this. Rapid scaling to come hopefully.
We just need to actually build those "cheap" wind and solar farms. More. Faster.
I enjoyed this episode and always love to hear about the work being done on climate tech. But something I also wonder when hearing episodes like this—you're talking to someone who owns a business, which means they're inherently motivated to say certain things. In other contexts this would be an unmitigated bad ("I interviewed the CEO of Exxon and they told me Exxon is great!) but it's obviously more complicated here. How do you think about striking the right balance?
One of the most fascinating parts to me was the distortion that 45Q (as expanded in the IRA) is having to low carbon solutions. Without a base carbon price it creates this really big hole of support for things like sublime. Hoping we find ways to address that.
I work in the trades and this brought me a lot of joy. It’s crazy to hear that cement cost 8% of the total emissions right now, but proud of Sublime and the work they’re doing!
P.s. if you took back your decision to let free readers make comment... I wouldn’t hold it against you... there are some interesting people making some interesting comments!
Thanks for your comment Natalie, we moderate on a daily basis, although sometimes a bad comment slips through for a few hours! IMO the experiment has been positive thus far, the vast majority of free comments have been on par with those from our paid subs. The bad ones are issued a warning, deleted or banned. Even paid subs have been known to cross a line...
However, we'll continue to evaluate the free commenting policy over the next few months to see if the juice is worth the squeeze. This should be a safe space for all to discuss Volts' content!
This seems pretty exciting--I hope it lives up to the hype. This seems like too much to ask, but does Sublime's concrete also ABSORB carbon over the decades, like regular concrete does?
If you want to understand the potential cost of this technology and similar technologies then look no further than the chlor-alkali process. The cost of production on an ecu (electro chemical unit) is $500-$600. Each unit produces ~1 ton of product NaOH and 1 ton of Cl2. This is a well-oiled process.
If we think about what Sublime is doing, technically cool, but they have some daunting problems ahead of them. I have a lot of questions: what is the electrical efficiency of the current process? How do you deal with essentially a slurry and delivering current (not easy, or efficient)? How do you dewater and dry the calcium hydroxide (notoriously difficult, slimes filters, stratifies in water, hard to spin down). Dewatering is very expensive both in capex and opex. You also have to dewater the silica.
Without a significant carbon tax or credit, I am afraid this will never reach critical velocity.
Shifting complex production systems to achieve nebulous socioecological goals risks reducing resources away from core system controls. One question must be answered correctly before drastic change occurs: Is the net-zero final product as good as or better than the current product in other terms? Quality, cost, reliability, ease of manufacture, ease of installation, and ease of disposal? If no, then, back to the drawing board.
How similar/different is the Brimstone process? The final product seems to be meeting different testing standards. Brimstone passed testing for ordinary portland cement, and Sublime produced something for hydraulic cement. I can't tell if that was just a choice the companies made as to which standard test against, or something intrinsic to the process, it looks like they're very similar testing.
They seem to be using the same raw material, calcium silicate mineral (basalt! the most common rock on earth for the win!). Brimstone doesn't seem to have talked about their chemical process, though, the way that Sublime has.
Managed to answer the question by relistening and checking if Brimstone had posted additional information. Brimstone is using a high temperature process, but haven’t revealed details, and decided to get certified as ordinary Portland cement. Sublime, as Ellis said in the episode and I just missed it, decided performance testing was the better route so they don’t have to use a high temp prowess to make the crystalline structure of OPC (at least i think that’s what she meant).
That is even cooler (heh) than Brimstone and I thought that was pretty cool.
It is great that several podcasts ago we had the carbon block of thermal battery (Antora, Andrew Ponec) to negate the heating side of natural gas boilers for cement (or steel). I am sure that Sublime and Antora can still successfully work on the same thing. But the use of another rock, basalt, besides limestone through hydrolysis, with zero CO2 emissions takes the cake.
There is a lot of promising work out there on decarbonizing cement. The Canary Media article cited several others but did not mention Green Cement. Green Cement does not use limestone to make its cement but instead uses fly ash and room temperature physical and chemical process to make essentially carbon free cement. Their product has Green Cement has now merged with another company to form EcoMaterials, https://ecomaterial.com/products-and-technologies/green-cement/ . Their product has been used in 50/50 mixtures with OPC to build roads and structures in Texas. Their 100% replacement for OPC, PozzoCEM, is still roughly 3x more costly but they believe it will come competitive over time. It is presently being used to create 3-D printed houses near Austin, Texas. Ref. https://www.forbes.com/sites/erikkobayashisolomon/2023/11/13/eco-materials-sustainable-green-cement-is-transforming-construction/?sh=6f0f11993404 .
David referenced a Medium article a couple of times during this cast. Can you please provide the link?
Leah was a great guest and I found this fascinating!
Hi Randy, here it is!
https://medium.com/@SublimeSystems/can-you-make-zero-carbon-cement-476d73892656
One question I have about this approach that I didn't hear discussed is what is the anticipated split between capital costs, electricity cost and other costs. With this and some other technologies, that's relevant to understanding whether they can be powered directly from intermittent electricity (and tolerate the duty cycle that implies) or need to be paired with batteries (or some other approach). I've seen plenty of discussion of this as a factor for green hydrogen given capital cost of electrolyzers so curious how this potentially compares.
Concrete manufacturing is a continuous process, you don't want to thermally cycle the facility for a variety of reasons including productivity, thermal inertia, undesired intermediary reactions, and thermal fatigue on the machinery. Lime calcination is likewise a continuous process and takes place at 900C (or above). These are not processes you can turn on and off in a week, much less to follow a daily duck curve; they have one or two scheduled shutdowns each year.
They are highly predictable, though, so you can closely match storage capacity and safety factor to daily demand year over year. As such, all manner of mechanical storage (pumped hydro, pressure) enters the frame and not just batteries or yet-not-scaled hydrogen meant to farm tax incentives in thermodynamically sub-optimal ways.
The big industries leverage simple and fool-proof processes that won't be going down regularly service and updates. It is called a stock pile because it is a pile... of stock. A large facility will have large yard full of stockpiles for inputs like aggregate and lime and outputs, but also coal for backup power. You won't find an Ops manager willing to accept a hydrogen backstop when their entire facility can be damaged if some part of a first generation (read untested) supply system breaks down or fails to deliver required power at the required time. And while the regular use requirement minimizes hydrogen's escape problems those problems make it a poor long term reserve storage solution - that backup supply for when things go wrong that piles of coal do so very well.
Thanks Geoff for this detailed answer, but it is answering a different question than I asked. Your explanation makes a lot of sense for why cement production as currently practiced can't/shouldn't be thermally cycled to follow power availability.
However, my question is regarding the proposed alternative cement production process which Sublime Systems is pursuing as described in this podcast. This does not involve high heat (and has several other differences) so different factors, if any, are likely to be at play for whether the process needs to operate continuously.
Also, my reference to hydrogen wasn't a proposal to use it to power cement production (which as you note has several drawbacks). Rather, since Sublime's process involves an electrolyzer (as does hydrogen production), I'm asking about the capital cost of that electrolyzer (and surrounding equipment) as a potential limiting factor on the feasibility of this proposal.
My understanding is that electrolyzers are reported to be well adapted to power intermittency. Another beneficial characteristic is that they can be modular & containerized, so that banks of containerized electrolysers provide redundancy & backup capacity for periodic maintenance & replacement. I suppose that ideally, electrolysers would be located as close as possible to large wind, solar &/or geothermal resources to take full advantage of off-peak power.
I deleted my original reply, because I was out over my skis trying to figure out what they are doing here and how they are going to succeed. There isn't enough information to know much about what they are doing, and while Sublime's Arpa-e grant (https://arpa-e.energy.gov/technologies/projects/electrochemical-synthesis-low-carbon-cement) mentioned off-peak renewable electricity and grid services that's just as likely the available funding pathway as a real story of industrial scale out.
Structurally, if you have a more expensive synthesis route and more expensive CapEx you cannot also bet on lower utilization to make up the difference. Some back of the envelope math puts the OpEx at $500/ton for Lime with $220/ton the delivered incumbent rate - for a final commodity that goes for $75/ton - a lot of work to do!
But it took Form Energy 7 years to explain what they were doing and everything shared by Sublime to date is "early stage startup ambiguous" - as it should be. Their facility *can* produce *up to* 100 tons of concrete each year. Their novel process makes lime, which comprises only 5-20% of that potential mass. They don't report how much they've made. In the few pictures of the facility online it is a very clean setup in a small corner of a large space. For their test samples they'd need about 30 lbs of lime to create the concrete to submit for the tests (3x cube and slump), but there is no reason to gate that recipe and method testing behind the novel feedstock synthesis work - it wouldn't be disingenuous to have commercially sourced the precursors for the test. They planned to have a field test of undetermined scope and scale by the end of this year - meaning they haven't hit that milestone previously. Recycling the working fluid and being clever with the concentration can greatly improve cost and speed of the process - but that's not a thing to talk about yet. As a company this early finds their first customer(s) and makes their first deliveries everything can change.
I wanted more, I want to understand how this is supposed to work; we got a tantalizing outline suitable for a Series A company still trying to figure that out for themselves.
This is such a cool development, literally and figuratively. It seems like Washington-Oregon would be a good place for plants to be established, looking at the combination of surficial basalt, inexpensive renewable energy, water transportation and "cap and invest" CO2 permit expenses that cement producers and consumers (I think) pay in this region. Electrolyzer talent is getting developed here too as work on a hydrogen hub ramps up. A major downstream destination for products from this region happens to be Portland, perhaps making a nice story, in transitioning "Portland cement."
https://en.wikipedia.org/wiki/Columbia_River_Basalt_Group
https://eerscmap.usgs.gov/uswtdb/viewer/#6.46/46.885/-120.126
https://www.commerce.wa.gov/news/us-dept-of-energy-selects-pacific-northwest-for-regional-clean-hydrogen-hub/
Thank you for sharing! Super interesting podcast. One thing I want to mention - in addition to decarbonizing the actual manufacturing process, with technologies like Sublime, there's also important work to be done by trading our building materials. Cement and concrete can't be entirely replaced, but companies like Biomason, which is replacing cement with biotechnology, and mass timber buildings, like Mjøstårnet in Norway, also have a role to play! The key to the sustainable transition is diversifying!
Nice. Leah seemed believable. I've been intrigued by my hometown folks doing something similar with iron/steel @ https://www.electra.earth/.
As with that, I keep asking... how much of that "cheap renewable electricity" is needed? In some Google searches there are returns with useable #s.
A pound of cement at the factory door sells for all of $0.06/lb. Of that, it seems like fuel cost is about $0.015/lb, less if trash tires are used.
Some #s in a wonky paper by Leah convert to 0.75 kWh/lb cement in the Sublime process. So at $0.04/kWh for those cheap renewables, it's $0.03/lb. Could be less in the right place and time. So an add in the range of $0.015/lb or 20% range. Not bad.
With the effect of the limestone CO2, GHGs fly out the stack at about 1 lb CO2/lb of cement. At the current $200ish+/tonne damage estimates, that's $0.09/lb of cement, which if applied would more than double that wholesale price. This illustrates the frustration mentioned with $0.04/lb available for post-combustion CCS or $0.08/lb for DAC CCS.
That's how I understand the #s. The H2 generated by the electrolyzers is used for some needed thermal heat. There would be other electricity involved with either process. I try not to get to enthralled w/revolutionary "cleantech," and always figured one of the few logical use cases for CCS is cement, but I like this. Rapid scaling to come hopefully.
We just need to actually build those "cheap" wind and solar farms. More. Faster.
I enjoyed this episode and always love to hear about the work being done on climate tech. But something I also wonder when hearing episodes like this—you're talking to someone who owns a business, which means they're inherently motivated to say certain things. In other contexts this would be an unmitigated bad ("I interviewed the CEO of Exxon and they told me Exxon is great!) but it's obviously more complicated here. How do you think about striking the right balance?
One of the most fascinating parts to me was the distortion that 45Q (as expanded in the IRA) is having to low carbon solutions. Without a base carbon price it creates this really big hole of support for things like sublime. Hoping we find ways to address that.
I work in the trades and this brought me a lot of joy. It’s crazy to hear that cement cost 8% of the total emissions right now, but proud of Sublime and the work they’re doing!
P.s. if you took back your decision to let free readers make comment... I wouldn’t hold it against you... there are some interesting people making some interesting comments!
Thanks for your comment Natalie, we moderate on a daily basis, although sometimes a bad comment slips through for a few hours! IMO the experiment has been positive thus far, the vast majority of free comments have been on par with those from our paid subs. The bad ones are issued a warning, deleted or banned. Even paid subs have been known to cross a line...
However, we'll continue to evaluate the free commenting policy over the next few months to see if the juice is worth the squeeze. This should be a safe space for all to discuss Volts' content!
David, I was going to share your post of this episode on Mastodon, but there's no post to share, grumble, grumble...
Cut, paste and send is really easy and there are a lot of climate interested people who want to see/listen to your stuff.
I'm going to share the link and tag you anyway...
@joeinwynnewood@mstdn.social
Blarg, Joe, I put it on Twitter, Threads, and Bluesky. There are only so many social media accounts one man can maintain!
Yeah, it's a pain, another reason to hate Musk.
That said, toss the hell site and you can replace it with Mastodon, a _much_ better place to be!
Seriously, Twitter traffic is reportedly way down & they're boosting shit postings reducing the value of time posting there.
I also question the value of Bluesky given both it's provenance and invite only population.
Lastly, if you take the X-last pledge - https://www.xlast.org/home#pledge - Twitter will go away for you sooner than later.
This seems pretty exciting--I hope it lives up to the hype. This seems like too much to ask, but does Sublime's concrete also ABSORB carbon over the decades, like regular concrete does?
If you want to understand the potential cost of this technology and similar technologies then look no further than the chlor-alkali process. The cost of production on an ecu (electro chemical unit) is $500-$600. Each unit produces ~1 ton of product NaOH and 1 ton of Cl2. This is a well-oiled process.
If we think about what Sublime is doing, technically cool, but they have some daunting problems ahead of them. I have a lot of questions: what is the electrical efficiency of the current process? How do you deal with essentially a slurry and delivering current (not easy, or efficient)? How do you dewater and dry the calcium hydroxide (notoriously difficult, slimes filters, stratifies in water, hard to spin down). Dewatering is very expensive both in capex and opex. You also have to dewater the silica.
Without a significant carbon tax or credit, I am afraid this will never reach critical velocity.
Shifting complex production systems to achieve nebulous socioecological goals risks reducing resources away from core system controls. One question must be answered correctly before drastic change occurs: Is the net-zero final product as good as or better than the current product in other terms? Quality, cost, reliability, ease of manufacture, ease of installation, and ease of disposal? If no, then, back to the drawing board.
How similar/different is the Brimstone process? The final product seems to be meeting different testing standards. Brimstone passed testing for ordinary portland cement, and Sublime produced something for hydraulic cement. I can't tell if that was just a choice the companies made as to which standard test against, or something intrinsic to the process, it looks like they're very similar testing.
They seem to be using the same raw material, calcium silicate mineral (basalt! the most common rock on earth for the win!). Brimstone doesn't seem to have talked about their chemical process, though, the way that Sublime has.
Anyone know?
Managed to answer the question by relistening and checking if Brimstone had posted additional information. Brimstone is using a high temperature process, but haven’t revealed details, and decided to get certified as ordinary Portland cement. Sublime, as Ellis said in the episode and I just missed it, decided performance testing was the better route so they don’t have to use a high temp prowess to make the crystalline structure of OPC (at least i think that’s what she meant).
That is even cooler (heh) than Brimstone and I thought that was pretty cool.
It is great that several podcasts ago we had the carbon block of thermal battery (Antora, Andrew Ponec) to negate the heating side of natural gas boilers for cement (or steel). I am sure that Sublime and Antora can still successfully work on the same thing. But the use of another rock, basalt, besides limestone through hydrolysis, with zero CO2 emissions takes the cake.
There is a lot of promising work out there on decarbonizing cement. The Canary Media article cited several others but did not mention Green Cement. Green Cement does not use limestone to make its cement but instead uses fly ash and room temperature physical and chemical process to make essentially carbon free cement. Their product has Green Cement has now merged with another company to form EcoMaterials, https://ecomaterial.com/products-and-technologies/green-cement/ . Their product has been used in 50/50 mixtures with OPC to build roads and structures in Texas. Their 100% replacement for OPC, PozzoCEM, is still roughly 3x more costly but they believe it will come competitive over time. It is presently being used to create 3-D printed houses near Austin, Texas. Ref. https://www.forbes.com/sites/erikkobayashisolomon/2023/11/13/eco-materials-sustainable-green-cement-is-transforming-construction/?sh=6f0f11993404 .
This is all I need, a one-hour lecture about cement during my Christmas week break. What terrible timing.