10 ms·

Cement's future could be a combination of carbon capture and electrification

111 points by hannob 3y ago

cschmidt 3y ago
Here's an interesting Economist article on the same subject: https://www.economist.com/science-and-technology/2023/06/07/a-finnish-firm-thinks-it-can-cut-industrial-carbon-emissions-by-a-third https://www.economist.com/science-and-technology/2023/06/07/...
- JumpCrisscross 3y ago
  I was just sent a Vox video on the topic. Someone is running a campaign.
samwillis 3y ago
The best way to reduce carbon emission from cement would be to use less of it. Here in the UK, 30% of the cost of a new house build is the foundations, the excavation, and then filling of a hole in the ground with many tons of concrete. I find it baffling how little innovation in construction has been adopted by the house building industry here. Light weight timber frame construction on pile foundations would massively reduce both the carbon footprint of the build and the cost. When I have made these arguments before, people often respond that our heavy weight brick construction is better as it withstands the weather more, and will last longer. But with modern materials (or good old traditional maintenance) thats just not true, a timber frame house can last hundreds of years. Finally, it's not just the carbon emissions from cement manufacturing that worries me. I live about 3 miles from a cement factory, and the amount of dust that it puts out is staggering. If I clean my car, within two days it's covered in a thin layer of dust thats locally attributed to the factory. I can't imagine thats good for our health!
- pjc50 3y ago
  How is the relative cost? Timber is historically much more expensive in the UK than in the US, the major user of timber construction.
  - samwillis 3y ago
    Correct, timber is expensive here - particularly over the last 3 years - but I believe a timber frame construction is still a little lower than a brick contraction in cost. SIPs (structurally insulated panels) are more expensive than brick, but I suspect that more to do with available expertise and the need for expensive cranes. (As an aside its fascinating visiting France where every house building site has a crane, none do here) But many timber frame houses here are still build on massive concrete slabs, and that is still pouring money into the ground. We need to adopt innovations like screw piles that are completely concrete free.
    - throwway120385 3y ago
      Having had to buck timber trusses to a second floor roof, I think cranes are a wonderful invention and we should have more of them.
- was_a_dev 3y ago
  I know we have wet and cold climate in the UK, but it is also pretty mild. We could have timber framed housing, as we don't get hit by natural disasters with the exception of flooding
- theluketaylor 3y ago
  For regions that don't have to worry about a frost line helical screw piles and mass timber are game-changing building capabilities to construct concrete free. It's even possible to build carbon negative thanks to the timber locked in the building. And it's way faster since you don't spend months preparing a site and building forms. Even frost line regions could dramatically cut their concrete usage if they just focused on protecting the water lines. You would lose a basement, but those are expensive per sq ft anyway. Just go up another floor for less total costs. Local building codes will get in the way since building inspectors tend to reject things they haven't seen before (like mass timber frame) and way too many places have incredibly strict height restrictions. It is incredible to watch helical screw piles go in. A friend needed 60+ posts installed for a big fence. Would have been days of digging or augering post holes down 4 ft for the frost line and then mixing hundreds of bags of cement and filling the holes with concrete. Instead a contractor with a small tracked machine that fit through a standard gate drove every pile in under an hour.
  - rafamvc 3y ago
    You can use helical screw piles in places with a frost line. As long as the blades are below the frost line.
    - theluketaylor 3y ago
      Absolutely true, but you still need a plan for protecting the water lines. You need some kind of underground insulated structure below the frost line that can handle direct dirt contact. Annoyingly concrete remains the best option.
      - blake1 3y ago
        Was recently in a fairly new construction house in a very cold climate state that did not have a full basement below the frost line. There was a partial 8’x8’ corner that sunk down to where the water line came in, but the rest of the footprint was a crawl space. Losing the basement does affect the style of building that is economical to build on top though, mainly due to building codes.
- nofeelings 3y ago
  Why aren’t they already doing that? If what you’re saying is true they would since the implication is that it’s cheaper.
  - replygirl 3y ago
    Same reason most people don't write Rust: The talent, best practices, and vendor ecosystem are less accessible. Similar to Rust it's much more accessible than people _think_ though
- dubcanada 3y ago
  > Light weight timber frame construction on pile foundations > But with modern materials (or good old traditional maintenance) thats just not true, a timber frame house can last hundreds of years. I am not sure were you are reading that "timber frame house can last hundreds of years" but I don't believe that is correct, most timber frame houses have an estimated 30 year life span. A stone/brick house can last thousands of years. I do agree that a stick frame/light weight timber house is way less concrete then a brick/stone house. But UK doesn't have a ton of trees, so the majority of those trees are imported from EU places like Belarus or Canada. Which is a bunch of gas in itself. Pile foundations also have tons of problems, and have a very high fail rate. They don't do well with salt water, so costal areas in UK will have problems, they don't do well with stone/bedrock. Which UK has a ton of. I believe there is tons of work to do, but I disagree that the solution is stick framing and pile foundations. I think the actual solution is innovation and reduction of some building standards to allow innovation. It's very very difficult to even experiment with building materials as every building code requires X insulation and any building official will complain if you have Y. So everyone just uses X. ICF for example is absolute garbage, its marketed as a eco friendly, green building material that's made from oil and filled with a truck load of cement. How that got classified as a "eco-friendly green building material" is beyond me. Meanwhile things that are actually eco-friendly like hemp, straw, etc all require a ton of engineering and have zero standards, so everything has to be engineered. And you'll get crazy looks from building officials when you ask for a review of your straw timber frame house.
  - theluketaylor 3y ago
    I live in a ballon-framed house built in 1926. Coming up on 100 years and with reasonable maintenance there is no reason it won't last another 100. There are some terribly built wooden houses that will just rot away, but it's not that hard to do it right. Wood as a building material when used properly can be incredibly resilient, especially with modern mass timber solutions rather than raw wood.
    - SoftTalker 3y ago
      Agree. My first house was a wood-frame bungalow built near the prior turn of the century. As long as you don't get termites, and maintain the roof and siding so you don't have water leaking in, wood houses will last basically forever, or at least on the order of 100 years.
- slothtrop 3y ago
  Cement is used in most city infrastructure, for industrial builds, etc. The demand for it in the U.S. probably dwarfs the UK several times over despite lumber use for houses, and poured concrete no longer popularly used for foundations. If you want to abate it, you'd need to look far beyond that particular use-case in the UK. I don't see low-hanging fruit here. Cement is reliable and inexpensive. There is R&D in the works for eco-cement, but this appears to be in early stages. It's possible to reduce emissions in its production in the first place. Notwithstanding the calcium carbonate, energy inputs (which are very high) could eventually not rely on fossil fuels. If the goal is to pursue an aggressive timeline for curbing CO2 emissions then probably CC & electrical will appear first.
- ZeroGravitas 3y ago
  Reduction is also item number 1 in their linked factsheet: https://fcarchitects.org/wp-content/uploads/2023/02/20230206_ENG_Cement-Factsheet_FCA-1.pdf https://fcarchitects.org/wp-content/uploads/2023/02/20230206... > Modernize building standards to favor low-carbon materials and circular use > Promote low-carbon practices in industry and curricula > Update building and infrastructure regulations based on required performance, instead of prescriptions on material conten
- londons_explore 3y ago
  There is a good argument that buildings shouldn't last so long. Buildings a mere 50 years ago probably have very poor insulation (and hence high heating/cooling environmental + monetary costs), have electrics that aren't considered safe today, have plumbing probably containing lots of lead, and are lacking amenities considered standard today (electrical outlet next to the bed for phone charging, mixer taps, etc). Those buildings probably won't resist fire for long, and probably won't be suitable for heat pump heating. Sound insulation probably won't be good, so you probably get woken by your neighbour having sex. All those things are fixable for a cost, or livable with a hit to quality of life, the environment, the house owners health, etc. If we assume that the requirements for a home continue to evolve, then we can see that something built today would be unlikely well suited for use in 50 years. Considering that, perhaps it's best to build something easy to disassemble and rebuild 50 years from now.
  - HPsquared 3y ago
    It's surely cheaper to rewire and refit, than to knock the whole thing down to the foundations and start again.
    - londons_explore 3y ago
      Doing all those things at once, it's usually cheaper to knock down and start from scratch. The problem lies in a homeowner who doesn't have much spare cash - so they rewire one year... and then a few years later they replumb... and then a few years later they replace the roof... etc. Overall, they spent more, but in small increments so it didn't feel like more. Typically regulations allow things to be 'grandfathered' - so renovating a house allows you to avoid getting permission to rebuild, which may be denied.
      - notahacker 3y ago
        The idea that periodic replumbing and rewiring and replacing roofing felt costs less overall than a complete rebuild is questionable enough in terms of financial cost, even more so in terms of carbon output cost. Sure, the [carbon] accounting looks a little different if you're having to pull out most of the load-bearing walls to accommodate a change of use and underpin to build on top or considering replacing old masonry with something built to maximise energy efficiency. But rebuilding entire houses to keep up with the latest fads in mobile charge ports and mixer taps is about as good for the environment as "fast fashion"!
- CalRobert 3y ago
  I had a house built in Ireland and the architect was a huge pain in the ass. She wanted concrete _ceilings_ ffs. In a single story dwelling. She also thought it was ludicrous I wasn't using concrete blocks, and anything like a pier or post and beam foundation was completely out of the question. The funny thing is that the houses here are pure shite so it's not like this approach has been working for them. Utter, abominable, crap. Ugly, too. I was able to get a timber frame and wood ceilings but still have a concrete foundation. The builders were so proud of it being an insulated foundation (KORE) but you wouldn't even _need_ that if the house were lifted off the ground, like it should be. I asked one forward-minded engineer about it and he said it was down to people being brainwashed by "concrete built is better built" ads from the 80's and centuries of complete deforestation.
- OrvalWintermute 3y ago
  > The best way to reduce carbon emission from cement would be to use less of it. Disagree. I think we need to return to the future through rediscovering Roman Concrete [1] and making structures that can last thousands of years. Concrete also, can be recycled and used again. Because we are in a deglaciation period currently, in general I am skeptical about moving to a low CO2 environment which is not normal for the earth. However, I am sensitive to the fact that we must be stewards and caretakers of the earth and make the best use of resources, while polluting less, and moving to a more sustainable future through a grand conversion process eventually. [1] https://news.mit.edu/2023/roman-concrete-durability-lime-casts-0106 https://news.mit.edu/2023/roman-concrete-durability-lime-cas...
luis_cho 3y ago
Why do we need more cement? In my country there are 2 houses for each family, and we in a housing crisis. Maybe the solution can be less speculation, a social solution instead of a technological one.
- robertlagrant 3y ago
  Three possible, not-mutually exclusive answers: - Fewer families now then before - Significant net movement of people (e.g. the UK took in 0.6m immigrants in 2022, pushing up housing requirements) resulting in more houses being needed in some locations even if the world had zero extra people - Cement isn't reusable, so once it's set it's only useful in that place
  - Velofellow 3y ago
    cement ≠ concrete, but concrete is indeed recyclable. I know TxDOT (likely other agencies and municipalities) allows its use, often as aggregate material for HMAC paving. The cured concrete is crushed, sorted by gradation and used accordingly. Concrete rubble can also be used in retaining walls along with some backfill applications. https://www.dot.state.tx.us/business/contractors_consultants/recycling/concrete_aggregate.htm https://www.dot.state.tx.us/business/contractors_consultants...
  - londons_explore 3y ago
    Most concrete products can be recycled. But, due to the very low cost of cement and other related products, it is rarely economical to transport end of life concrete far to be reused. However, if there are effective taxes on disposing of concrete (as there are throughout the EU+UK), then concrete does tend to get reused.
- slothtrop 3y ago
  Even if you want to increase density, you'd need concrete to achieve it. Cost of housing is inversely correlated to the rate of new builds in cities, and the reason is the growth in demand through immigration. Can't have your cake and eat it too: want more immigration? Build more. > a social solution Such as what, coercing multiple families to share detached homes? Would you volunteer for that? And how far do we expect to push that when the demand for housing will keep growing?
Fyrezerk 3y ago
This article isn't very clear on the fact that CO2 can be re-injected back into the cement later in the production stage. I work with a startup using direct air capture tech to capture ambient CO2, store it, and inject it back into cement production. This has a massive offset in the CO2 produced during the calcination stage. https://www.carbon-direct.com/insights/direct-air-capture-to-concrete-2-2 https://www.carbon-direct.com/insights/direct-air-capture-to... There is also lots of work already underway on electrified calcination. Plenty of industries, such as carbon fiber production, already take advantage of electrified kilns in their production process. This tech just needs to be scaled up. As the article mentioned, cement manufacturing isn't exactly on the cutting edge of technology.
- NathanaelRea 3y ago
  How much compressive stress is lost when you aerate concrete? Would consolidation with a concrete vibrator release the CO2 like shaking a soda?
  - Fyrezerk 3y ago
    [flagged]
- labster 3y ago
  How is the carbon bound in the concrete? I doubt CO2 bubbles would last very long, so is it just forming carbonates?
  - Fyrezerk 3y ago
    [dupe]
- megaman821 3y ago
  Won't cement slowly reabsorb half of the CO2 it released when making it (excluding the heating part)? What is the big advantage to making it reabsorb it early in its lifetime?
  - 3y ago
roywashere 3y ago
I think it is interesting to see that hannob who wrote many articles on IT security now seems to have pivoted to covering ‘green and energy’ topics. All submissions to HN in the last year are not about IT!
LatteLazy 3y ago
We need as many ways to theoretically cut emissions as possible. That way, no one way will ever have to be chosen by a majority of people. So we will never have to actually do any of them. And we can keep polluting but pretend "it's not my fault because I supported <insert random niche idea>". No one wants to admit they are happy to just ruin everything. So we all need to pretend we want action. But in order to prevent any action happening we need to pick different things. The Nuclear people won't vote for solar expansion, the solar people will deny windmills work, the windmill people will refuse to condone nuclear. That way EVERYONE can claim the moral high ground AND use nice cheap, reliable coal. The same applies for everything (electric cars? No! Hydrogen!. Hydrogen? No, public transport! Public transport? No, electric cars!).
- gs17 3y ago
  > The Nuclear people won't vote for solar expansion, the solar people will deny windmills work, the windmill people will refuse to condone nuclear. I have only ever seen the last of these outside of people selling something.
  - LatteLazy 3y ago
    Go look at any HN article on either and you will find people talking about wind farms being ugly, being intermittent, making noise, killing birds etc. The point being that no solution is perfect and by refusing any imperfect solution we get what we really want: no action.
- yazaddaruvala 3y ago
  I understand why you feel demotivated by all of this negative discourse and constant speculation on better technology. That said, > electric cars? No! The Model Y was the best selling car[0] in the world in Q1! Isn't that a positive fact :) Six Flags in California now has solar installed at 2 of its theme parks, offsetting 3000 homes worth of electricity! Isn't that a positive fact :) There are many other stories like this, you just have to look :) > So we will never have to actually do any of them. I agree we can do more, but focus on these positive outcomes! Stuff IS happening and it is for the better! [0] https://finance.yahoo.com/news/tesla-model-y-was-the-best-selling-car-worldwide-in-the-first-quarter-154909234.html https://finance.yahoo.com/news/tesla-model-y-was-the-best-se... [1] https://pv-magazine-usa.com/2023/04/25/six-flags-announces-solar-plus-storage-carport-at-los-angeles-theme-park/ https://pv-magazine-usa.com/2023/04/25/six-flags-announces-s...
Faaak 3y ago
Mixing biochar with concrete actually makes it harder (or you can add less cement to it), while storing CO₂ (biochar is a viable CO₂ pit). Can't link the sources because mobile, but if you're interested look it up, it's really interesting. It's being certified in France right now.
photochemsyn 3y ago
Seawater is a source of calcium, and it looks like desalination concentrate is an option for limited scale production: https://www.nature.com/articles/s41545-022-00153-6 https://www.nature.com/articles/s41545-022-00153-6 "Seawater desalination concentrate—a new frontier for sustainable mining of valuable minerals" (2022) > "The metallic elements found in the highest concentration are sodium, magnesium, calcium and potassium, which have been commercially extracted as the chlorides, sulfates, and carbonates while magnesium has been extracted as the hydroxide."
pfdietz 3y ago
The most interesting thing I saw in that article was the rotating air heater. Induce turbulence and shock waves in air and heat to very high temperature, without having a resistive heating element that has to be at least that hot. If you are going with electrical energy -> heat, you can get energy storage for free. It's much cheaper to store a kWh of high grade heat as sensible heat than it is to store a kWh of electrical energy in a battery. So electrification of cement production will be able to act as a large amount of dispatchable demand, simply by tacking on a heat store.

111 points by hannob 3y ago

Here's an interesting Economist article on the same subject: https://www.economist.com/science-and-technology/2023/06/07/a-finnish-firm-thinks-it-can-cut-industrial-carbon-emissions-by-a-third https://www.economist.com/science-and-technology/2023/06/07/...

JumpCrisscross 3y ago
I was just sent a Vox video on the topic. Someone is running a campaign.

samwillis 3y ago

The best way to reduce carbon emission from cement would be to use less of it. Here in the UK, 30% of the cost of a new house build is the foundations, the excavation, and then filling of a hole in the ground with many tons of concrete. I find it baffling how little innovation in construction has been adopted by the house building industry here. Light weight timber frame construction on pile foundations would massively reduce both the carbon footprint of the build and the cost. When I have made these arguments before, people often respond that our heavy weight brick construction is better as it withstands the weather more, and will last longer. But with modern materials (or good old traditional maintenance) thats just not true, a timber frame house can last hundreds of years. Finally, it's not just the carbon emissions from cement manufacturing that worries me. I live about 3 miles from a cement factory, and the amount of dust that it puts out is staggering. If I clean my car, within two days it's covered in a thin layer of dust thats locally attributed to the factory. I can't imagine thats good for our health!

pjc50 3y ago
How is the relative cost? Timber is historically much more expensive in the UK than in the US, the major user of timber construction.
- samwillis 3y ago
  Correct, timber is expensive here - particularly over the last 3 years - but I believe a timber frame construction is still a little lower than a brick contraction in cost. SIPs (structurally insulated panels) are more expensive than brick, but I suspect that more to do with available expertise and the need for expensive cranes. (As an aside its fascinating visiting France where every house building site has a crane, none do here) But many timber frame houses here are still build on massive concrete slabs, and that is still pouring money into the ground. We need to adopt innovations like screw piles that are completely concrete free.
  - throwway120385 3y ago
    Having had to buck timber trusses to a second floor roof, I think cranes are a wonderful invention and we should have more of them.
was_a_dev 3y ago
I know we have wet and cold climate in the UK, but it is also pretty mild. We could have timber framed housing, as we don't get hit by natural disasters with the exception of flooding
theluketaylor 3y ago
For regions that don't have to worry about a frost line helical screw piles and mass timber are game-changing building capabilities to construct concrete free. It's even possible to build carbon negative thanks to the timber locked in the building. And it's way faster since you don't spend months preparing a site and building forms. Even frost line regions could dramatically cut their concrete usage if they just focused on protecting the water lines. You would lose a basement, but those are expensive per sq ft anyway. Just go up another floor for less total costs. Local building codes will get in the way since building inspectors tend to reject things they haven't seen before (like mass timber frame) and way too many places have incredibly strict height restrictions. It is incredible to watch helical screw piles go in. A friend needed 60+ posts installed for a big fence. Would have been days of digging or augering post holes down 4 ft for the frost line and then mixing hundreds of bags of cement and filling the holes with concrete. Instead a contractor with a small tracked machine that fit through a standard gate drove every pile in under an hour.
- rafamvc 3y ago
  You can use helical screw piles in places with a frost line. As long as the blades are below the frost line.
  - theluketaylor 3y ago
    Absolutely true, but you still need a plan for protecting the water lines. You need some kind of underground insulated structure below the frost line that can handle direct dirt contact. Annoyingly concrete remains the best option.
    - blake1 3y ago
      Was recently in a fairly new construction house in a very cold climate state that did not have a full basement below the frost line. There was a partial 8’x8’ corner that sunk down to where the water line came in, but the rest of the footprint was a crawl space. Losing the basement does affect the style of building that is economical to build on top though, mainly due to building codes.
nofeelings 3y ago
Why aren’t they already doing that? If what you’re saying is true they would since the implication is that it’s cheaper.
- replygirl 3y ago
  Same reason most people don't write Rust: The talent, best practices, and vendor ecosystem are less accessible. Similar to Rust it's much more accessible than people _think_ though
dubcanada 3y ago
> Light weight timber frame construction on pile foundations > But with modern materials (or good old traditional maintenance) thats just not true, a timber frame house can last hundreds of years. I am not sure were you are reading that "timber frame house can last hundreds of years" but I don't believe that is correct, most timber frame houses have an estimated 30 year life span. A stone/brick house can last thousands of years. I do agree that a stick frame/light weight timber house is way less concrete then a brick/stone house. But UK doesn't have a ton of trees, so the majority of those trees are imported from EU places like Belarus or Canada. Which is a bunch of gas in itself. Pile foundations also have tons of problems, and have a very high fail rate. They don't do well with salt water, so costal areas in UK will have problems, they don't do well with stone/bedrock. Which UK has a ton of. I believe there is tons of work to do, but I disagree that the solution is stick framing and pile foundations. I think the actual solution is innovation and reduction of some building standards to allow innovation. It's very very difficult to even experiment with building materials as every building code requires X insulation and any building official will complain if you have Y. So everyone just uses X. ICF for example is absolute garbage, its marketed as a eco friendly, green building material that's made from oil and filled with a truck load of cement. How that got classified as a "eco-friendly green building material" is beyond me. Meanwhile things that are actually eco-friendly like hemp, straw, etc all require a ton of engineering and have zero standards, so everything has to be engineered. And you'll get crazy looks from building officials when you ask for a review of your straw timber frame house.
- theluketaylor 3y ago
  I live in a ballon-framed house built in 1926. Coming up on 100 years and with reasonable maintenance there is no reason it won't last another 100. There are some terribly built wooden houses that will just rot away, but it's not that hard to do it right. Wood as a building material when used properly can be incredibly resilient, especially with modern mass timber solutions rather than raw wood.
  - SoftTalker 3y ago
    Agree. My first house was a wood-frame bungalow built near the prior turn of the century. As long as you don't get termites, and maintain the roof and siding so you don't have water leaking in, wood houses will last basically forever, or at least on the order of 100 years.
slothtrop 3y ago
Cement is used in most city infrastructure, for industrial builds, etc. The demand for it in the U.S. probably dwarfs the UK several times over despite lumber use for houses, and poured concrete no longer popularly used for foundations. If you want to abate it, you'd need to look far beyond that particular use-case in the UK. I don't see low-hanging fruit here. Cement is reliable and inexpensive. There is R&D in the works for eco-cement, but this appears to be in early stages. It's possible to reduce emissions in its production in the first place. Notwithstanding the calcium carbonate, energy inputs (which are very high) could eventually not rely on fossil fuels. If the goal is to pursue an aggressive timeline for curbing CO2 emissions then probably CC & electrical will appear first.
ZeroGravitas 3y ago
Reduction is also item number 1 in their linked factsheet: https://fcarchitects.org/wp-content/uploads/2023/02/20230206_ENG_Cement-Factsheet_FCA-1.pdf https://fcarchitects.org/wp-content/uploads/2023/02/20230206... > Modernize building standards to favor low-carbon materials and circular use > Promote low-carbon practices in industry and curricula > Update building and infrastructure regulations based on required performance, instead of prescriptions on material conten
londons_explore 3y ago
There is a good argument that buildings shouldn't last so long. Buildings a mere 50 years ago probably have very poor insulation (and hence high heating/cooling environmental + monetary costs), have electrics that aren't considered safe today, have plumbing probably containing lots of lead, and are lacking amenities considered standard today (electrical outlet next to the bed for phone charging, mixer taps, etc). Those buildings probably won't resist fire for long, and probably won't be suitable for heat pump heating. Sound insulation probably won't be good, so you probably get woken by your neighbour having sex. All those things are fixable for a cost, or livable with a hit to quality of life, the environment, the house owners health, etc. If we assume that the requirements for a home continue to evolve, then we can see that something built today would be unlikely well suited for use in 50 years. Considering that, perhaps it's best to build something easy to disassemble and rebuild 50 years from now.
- HPsquared 3y ago
  It's surely cheaper to rewire and refit, than to knock the whole thing down to the foundations and start again.
  - londons_explore 3y ago
    Doing all those things at once, it's usually cheaper to knock down and start from scratch. The problem lies in a homeowner who doesn't have much spare cash - so they rewire one year... and then a few years later they replumb... and then a few years later they replace the roof... etc. Overall, they spent more, but in small increments so it didn't feel like more. Typically regulations allow things to be 'grandfathered' - so renovating a house allows you to avoid getting permission to rebuild, which may be denied.
    - notahacker 3y ago
      The idea that periodic replumbing and rewiring and replacing roofing felt costs less overall than a complete rebuild is questionable enough in terms of financial cost, even more so in terms of carbon output cost. Sure, the [carbon] accounting looks a little different if you're having to pull out most of the load-bearing walls to accommodate a change of use and underpin to build on top or considering replacing old masonry with something built to maximise energy efficiency. But rebuilding entire houses to keep up with the latest fads in mobile charge ports and mixer taps is about as good for the environment as "fast fashion"!
CalRobert 3y ago
I had a house built in Ireland and the architect was a huge pain in the ass. She wanted concrete _ceilings_ ffs. In a single story dwelling. She also thought it was ludicrous I wasn't using concrete blocks, and anything like a pier or post and beam foundation was completely out of the question. The funny thing is that the houses here are pure shite so it's not like this approach has been working for them. Utter, abominable, crap. Ugly, too. I was able to get a timber frame and wood ceilings but still have a concrete foundation. The builders were so proud of it being an insulated foundation (KORE) but you wouldn't even _need_ that if the house were lifted off the ground, like it should be. I asked one forward-minded engineer about it and he said it was down to people being brainwashed by "concrete built is better built" ads from the 80's and centuries of complete deforestation.
OrvalWintermute 3y ago
> The best way to reduce carbon emission from cement would be to use less of it. Disagree. I think we need to return to the future through rediscovering Roman Concrete [1] and making structures that can last thousands of years. Concrete also, can be recycled and used again. Because we are in a deglaciation period currently, in general I am skeptical about moving to a low CO2 environment which is not normal for the earth. However, I am sensitive to the fact that we must be stewards and caretakers of the earth and make the best use of resources, while polluting less, and moving to a more sustainable future through a grand conversion process eventually. [1] https://news.mit.edu/2023/roman-concrete-durability-lime-casts-0106 https://news.mit.edu/2023/roman-concrete-durability-lime-cas...

luis_cho 3y ago

Why do we need more cement? In my country there are 2 houses for each family, and we in a housing crisis. Maybe the solution can be less speculation, a social solution instead of a technological one.

robertlagrant 3y ago
Three possible, not-mutually exclusive answers: - Fewer families now then before - Significant net movement of people (e.g. the UK took in 0.6m immigrants in 2022, pushing up housing requirements) resulting in more houses being needed in some locations even if the world had zero extra people - Cement isn't reusable, so once it's set it's only useful in that place
- Velofellow 3y ago
  cement ≠ concrete, but concrete is indeed recyclable. I know TxDOT (likely other agencies and municipalities) allows its use, often as aggregate material for HMAC paving. The cured concrete is crushed, sorted by gradation and used accordingly. Concrete rubble can also be used in retaining walls along with some backfill applications. https://www.dot.state.tx.us/business/contractors_consultants/recycling/concrete_aggregate.htm https://www.dot.state.tx.us/business/contractors_consultants...
- londons_explore 3y ago
  Most concrete products can be recycled. But, due to the very low cost of cement and other related products, it is rarely economical to transport end of life concrete far to be reused. However, if there are effective taxes on disposing of concrete (as there are throughout the EU+UK), then concrete does tend to get reused.
slothtrop 3y ago
Even if you want to increase density, you'd need concrete to achieve it. Cost of housing is inversely correlated to the rate of new builds in cities, and the reason is the growth in demand through immigration. Can't have your cake and eat it too: want more immigration? Build more. > a social solution Such as what, coercing multiple families to share detached homes? Would you volunteer for that? And how far do we expect to push that when the demand for housing will keep growing?

Fyrezerk 3y ago

This article isn't very clear on the fact that CO2 can be re-injected back into the cement later in the production stage. I work with a startup using direct air capture tech to capture ambient CO2, store it, and inject it back into cement production. This has a massive offset in the CO2 produced during the calcination stage. https://www.carbon-direct.com/insights/direct-air-capture-to-concrete-2-2 https://www.carbon-direct.com/insights/direct-air-capture-to... There is also lots of work already underway on electrified calcination. Plenty of industries, such as carbon fiber production, already take advantage of electrified kilns in their production process. This tech just needs to be scaled up. As the article mentioned, cement manufacturing isn't exactly on the cutting edge of technology.

NathanaelRea 3y ago
How much compressive stress is lost when you aerate concrete? Would consolidation with a concrete vibrator release the CO2 like shaking a soda?
- Fyrezerk 3y ago
  [flagged]
labster 3y ago
How is the carbon bound in the concrete? I doubt CO2 bubbles would last very long, so is it just forming carbonates?
- Fyrezerk 3y ago
  [dupe]
megaman821 3y ago
Won't cement slowly reabsorb half of the CO2 it released when making it (excluding the heating part)? What is the big advantage to making it reabsorb it early in its lifetime?
- 3y ago

roywashere 3y ago

I think it is interesting to see that hannob who wrote many articles on IT security now seems to have pivoted to covering ‘green and energy’ topics. All submissions to HN in the last year are not about IT!

LatteLazy 3y ago

We need as many ways to theoretically cut emissions as possible. That way, no one way will ever have to be chosen by a majority of people. So we will never have to actually do any of them. And we can keep polluting but pretend "it's not my fault because I supported <insert random niche idea>". No one wants to admit they are happy to just ruin everything. So we all need to pretend we want action. But in order to prevent any action happening we need to pick different things. The Nuclear people won't vote for solar expansion, the solar people will deny windmills work, the windmill people will refuse to condone nuclear. That way EVERYONE can claim the moral high ground AND use nice cheap, reliable coal. The same applies for everything (electric cars? No! Hydrogen!. Hydrogen? No, public transport! Public transport? No, electric cars!).

gs17 3y ago
> The Nuclear people won't vote for solar expansion, the solar people will deny windmills work, the windmill people will refuse to condone nuclear. I have only ever seen the last of these outside of people selling something.
- LatteLazy 3y ago
  Go look at any HN article on either and you will find people talking about wind farms being ugly, being intermittent, making noise, killing birds etc. The point being that no solution is perfect and by refusing any imperfect solution we get what we really want: no action.
yazaddaruvala 3y ago
I understand why you feel demotivated by all of this negative discourse and constant speculation on better technology. That said, > electric cars? No! The Model Y was the best selling car[0] in the world in Q1! Isn't that a positive fact :) Six Flags in California now has solar installed at 2 of its theme parks, offsetting 3000 homes worth of electricity! Isn't that a positive fact :) There are many other stories like this, you just have to look :) > So we will never have to actually do any of them. I agree we can do more, but focus on these positive outcomes! Stuff IS happening and it is for the better! [0] https://finance.yahoo.com/news/tesla-model-y-was-the-best-selling-car-worldwide-in-the-first-quarter-154909234.html https://finance.yahoo.com/news/tesla-model-y-was-the-best-se... [1] https://pv-magazine-usa.com/2023/04/25/six-flags-announces-solar-plus-storage-carport-at-los-angeles-theme-park/ https://pv-magazine-usa.com/2023/04/25/six-flags-announces-s...

Faaak 3y ago

Mixing biochar with concrete actually makes it harder (or you can add less cement to it), while storing CO₂ (biochar is a viable CO₂ pit). Can't link the sources because mobile, but if you're interested look it up, it's really interesting. It's being certified in France right now.

photochemsyn 3y ago

Seawater is a source of calcium, and it looks like desalination concentrate is an option for limited scale production: https://www.nature.com/articles/s41545-022-00153-6 https://www.nature.com/articles/s41545-022-00153-6 "Seawater desalination concentrate—a new frontier for sustainable mining of valuable minerals" (2022) > "The metallic elements found in the highest concentration are sodium, magnesium, calcium and potassium, which have been commercially extracted as the chlorides, sulfates, and carbonates while magnesium has been extracted as the hydroxide."

pfdietz 3y ago

The most interesting thing I saw in that article was the rotating air heater. Induce turbulence and shock waves in air and heat to very high temperature, without having a resistive heating element that has to be at least that hot. If you are going with electrical energy -> heat, you can get energy storage for free. It's much cheaper to store a kWh of high grade heat as sensible heat than it is to store a kWh of electrical energy in a battery. So electrification of cement production will be able to act as a large amount of dispatchable demand, simply by tacking on a heat store.