9 ms·

Are we stuck with cement?

• adrianN 8y ago
  We just need a carbon tax that appropriately prices the pollution in. Just set up a market where people can trade carbon and companies can make money by sequestering carbon out of the atmosphere.
  • gmueckl 8y ago
    Sequestration should not be part of a market for CO2 certificates. Sure, you could earn money by sequestering CO2 and selling certificates generated by the process. But you will have to buy them back when the CO2 leaks. And it should diffuse out of the atirahe over time, albeit slowly. So you might eventually have to buy back the certificates instead of earning the money required to maintain the filled up CO2 storage for, well, virtually forever.
    • vpribish 8y ago
      that sure seems like it's workable though. take the money, invest it, pay out later. like a bank, or an insurance company.
    • Fjolsvith 8y ago
      So a company that plants trees could earn money under this system?
      • strommen 8y ago
        A company that converts clear-cut land to forest could earn money. There is an entire sector of the economy dedicated to voluntary carbon offsets, and re-forestation efforts are the primary supply. People and companies use these as a sort of carbon tax to offset the emissions they cause by taking airline flights, hosting events, or just living their daily lives.
      • tengbretson 8y ago
        Trees are not a form of permanent sequestration.
        • mchannon 8y ago
          Trees are a step that can either lead to permanent sequestration, or can lead to open-cycle sequestration, both of which are better than nothing. The carbon in a tree can get pulled out of the equation for decades while it grows, and partly slow-released as it rots on the forest floor, and partly adapted into the soil, some of which will eventually become a sequestered fossil fuel deposit. Alternatively, part of the tree can become food, or lumber, or paper, and whatever those eventually decay into may be, at least in part, things other than methane and CO2, safe in the ground as permanent sequestration. Trees aren't a panacea, but they're a tool we dare not discount out of hand.
        • adrianN 8y ago
          You can cut them down, turn them into charcoal and bury the coal. It is then sequestered for at least a few hundred years, likely much longer.
  • amluto 8y ago
    It’s not at all clear to me why carbon trading is useful. If a ton of CO2 emission is taxed $5 and a ton of capture is credited $5, what’s the point of trading certificates?
    • phamilton 8y ago
      My understanding is that with hard caps on CO2 emissions, a market rate for carbon will emerge. In other words, if you can buy a maximum of 100 tons of CO2 emission for $5/ton via a government agency, then at some point you'll have to buy credits from other parties, and that'll command a premium.
    • earthboundkid 8y ago
      It helps ensure that the financial sector controls everything in our economic system by giving them an excess of money that they can use to buy politicians.
    • stevesimmons 8y ago
      ... because the people doing the emitting are different from the people doing the capturing?
    • IkmoIkmo 8y ago
      How I understand it is this: Everyone creates 100 units of pollution together, say ten firms producing 10 units each. Then they say, you can only use 90 next year, 70 the next decade, 50 the decade after. Everyone needs to reduce pollution a bit, this is hard. Some have a 50 year investment in a factory that they can't remodel to pollute less. They'd need to shut down. Others are more flexible, they can remodel existing infrastructure, or shut down ones that are near the end of their lifetime. But why would they make investments in something more clean? Trading means one firm producing 10 units can invest in efficiency. Next year it's allowed to produce 9, but its new tech only produces 5. It can sell the other 4 to four factories which couldn't reduce their emissions from 10 to 9. Over time the polluting parties have funded the non-polluting parties' clean technology, while over time the total pollution has gone down. Moreover, it'll incentivise the lowest-hanging fruit approach, i.e. reduce emissions where it's cheapest to do so, first. That's why it's called cap-and-trade, not just trade.
  • skosch 8y ago
    Fortunately, the political will for carbon pricing is growing. The one obstacle is that conservative politicians are scared of using the word "tax" – so the current strategy is to push for a bill that would return all of the money to citizens ("carbon dividends" are an easier sell than "carbon taxes"). Here are the biggest organizations pushing for this — support them if you can: – https://citizensclimatelobby.org/ https://citizensclimatelobby.org/ (strictly bipartisan) – https://www.clcouncil.org/ https://www.clcouncil.org/ and their PAC, https://twitter.com/afcdividends https://twitter.com/afcdividends (conservative/industry-backed) – https://allianceformarketsolutions.org/ https://allianceformarketsolutions.org/ (conservative) – https://www.s4cd.org/ https://www.s4cd.org/ (campus-based)
• ramchip 8y ago
  > The turbine will produce about three megawatts of energy on average which, when working at full capacity, is enough to power 2,400 U.S. homes for one month. The "for one month" makes no sense here, but if you drop it the math checks out.
  • xyzzyz 8y ago
    Additionally, it won’t work at full capacity all of the time. The capacity factors as seen in actual existing commercial installations usually range betweeen 40% and 60%, so the average power output here will be rather 1-1.7 MW instead of 3 MW
  • dredmorbius 8y ago
    Clarifying further: Megawatts are a unit of power. Think of the size of the engine in a car. Megawatt-hours are a unit of energy. Think of the size of a fuel tank. Both units are useful: if you run a 1 MW load (a synonym, mostly, for power) for an hour, you'll use one MWh of energy, and have to fuel or pay equivalently. But increasing the size of your gas tank won't make your car more powerful, and increasing the engine size won't let you drive further between fuel stops.[1] That serious information outlets still confuse the terms is a bit sad really. _______________________________ Notes: 1. Pedants, I love you, welcome to Costco. But I'm excluding second-order effects, which tend regardless to be in the opposite directions.
  • cup-of-tea 8y ago
    Or three times that many homes in Europe. US power usage shouldn't be used as a benchmark.
    • throwaway76543 8y ago
      Where in Europe? There's a variance in the average consumption of over 400% depending on the weather. France uses much less energy than the US on average, but Sweden uses more. We see the same variance regionally within the US as well. Canadians use more energy per capita than folks in the US. Cold and hot states dominate energy consumption per capita. The US does have larger homes and more wealth and does tend to consume more energy per capita across similar environments -- but regional weather patterns create far, far larger differences in energy consumption than any other factor. We could just as easily say that Europe shouldn't be used as a benchmark as the weather is too nice, on average.
• sandworm101 8y ago
  >>And due to their lack of scientific acumen, they’ve focused on using different raw material mixers for cement which are introduced after the carbon intensive portion of the process. That someone does not share your goals says nothing of their scientific acumen. There are plenty of intelligent scientists working in the concrete industry. Their priorities may be different, but they are not bad scientists. Concrete is also a consumer product. Real change has to come from the architects and engineers who create the demand. But finding a true low-carbon alternative, a real alternative, is exceptionally difficult. Properly designed and maintained concrete structures can last centuries.
  • jessaustin 8y ago
    Centuries? Doesn't the material lose much of its strength when the rebar rusts away, which it certainly does in a century?
    • coryrc 8y ago
      It doesn't have to; the deeper the rebar the longer it will last. Rust takes more space than iron, so it can't form if the integrity of the concrete is uncompromised. You have to weigh the extra concrete against the likelihood the structure will be obsolete anyway. Building a 4-lane floating bridge across Lake Washington that drains runoff directly to the lake wouldn't have mattered if it would have lasted longer because it was too small and environmentally damaging in other ways.
    • sandworm101 8y ago
      Many concrete structures don't use rebar. Only "reinforced concrete" worries about rust. A concrete brick is all but immortal.
    • mchannon 8y ago
      Galvanic protection prevents rebar rusting. In places like the Bay Area, if you look around major concrete structures, you'll see "anodic protection" plates on the ground which contain large blocks of zinc. As long as you keep that zinc block fresh and the circuit intact, rebar will never rust. Some protection also uses electrical power. I seem to recall there's a bridge somewhere that uses solar power to keep its rebar from rusting.
• crankylinuxuser 8y ago
  > “We have created the Ferrari, now we need to create the Ford,” Ulm said. No, you put a racing stripe and a spoiler on a dumptruck, and then talked about its aerodynamic qualities. Not all industries are happy about ecological actions. That game will have winners and losers.. The Earth as a biosphere will "win", but there's a lot of industries that lose. Last I checked, the Earth's biosphere isn't paying the politicians. The dirty companies, well, they are.
• realandreskytt 8y ago
  Afaik the way cement works is you separate carbon from stone during its production and it binds co2 from air during setting. So wheres the big impact?
  • NegativeLatency 8y ago
    The “separate carbon from stone” step is not 100% efficient
  • mchannon 8y ago
    It doesn't bind CO2 from air during setting- that's the disconnect. By converting the carbonate to oxide, the calcium in cement is free to bond with silicates (and to a lesser extent other compounds). That CO2 released during manufacture is now looking for a new home, which could either be a plant, or a weathering deposit of limestone which could use the CO2 in the air to convert its own carbonate to stable bicarbonate.
  • dzhiurgis 8y ago
    At some point it must be cheaper to just cut a massive piece of rock and ship it to the construction site, isn't it?
    • Gibbon1 8y ago
      I've wondered about that of late. Assuming that fitting stone work was is a skilled craft. But with modern CNC technologies might be worth a look again.
    • HeyLaughingBoy 8y ago
      Depends. Are you taking into account reconfiguring bridges and overpasses to make the loads fit, or factoring traffic management costs into the equation? The truckloads of concrete to make a structure individually take up a lot less space and weigh less than the final structure itself.
• timwaagh 8y ago
  im in, where can i buy this? where can i invest? ah thats right...nowhere. the problem is not the industry. the problem is the people who write this and complain about it have not taken any steps to bring these more sustainable cements to market.
  • aoner 8y ago
    The problem is actually the industry. Many companies have tried, but keep failing. There is a really insightful report why innovation is stopped by huge barriers in the industry: https://www.sciencedirect.com/science/article/pii/S2210422415300228 https://www.sciencedirect.com/science/article/pii/S221042241... The development of more sustainable cements is a challenging but urgent venture. Demand-oriented knowledge formation and the reliance on existing prescriptive standards impede progress towards more sustainable alternatives to conventional cements. None-the-less the last years saw the emergence of a number of technology based start-ups with ambitions to introduce new low-carbon cements as alternatives to traditional Ordinary Portland Cement (OPC). An overall analysis of the Technological Innovation System for cement technology is conducted. This is extended with an investigation of how three start-ups, Celitement, Novacem and Calera perform within this environment. The implementation of new materials requires new types of collaboration between R&D and market actors, a combination of synthetic with the existing analytic knowledge base and redefinition of standards and norms. Moreover, a close cooperation of incumbent actors along the construction value chain is precondition for success of disruptive innovations.
    • timwaagh 8y ago
      oh pity. i figured they'd be just about begging for the stuff if it is reasonably priced since the millenials buying houses right now would be happy to buy anything that said 'built sustainably' if the price is reasonable. apparently it is not that easy.
    • deleted 8y ago
      [deleted]
• mabbo 8y ago
  There's a difference between a one-time cost and a variable cost. "Spending" carbon (via concrete) in order to reduce society's "spending" of carbon (via infrastructure improvements) should usually come out to a net gain. It's an investment. While I agree we need to include all costs in the accounting and improve the concrete industry as well, we shouldn't let the fact that carbon is emitted by concrete creation stop us from making these investments.
  • _jal 8y ago
    Sure. Many things are. The question is not whether concrete is a marvelously useful material; the question is whether other materials might have fewer negative externalities without compromising function. Note that you can rewrite that notion to discourage thinking about replacements for lots of things in the modern economy. Oil is a major input into nearly all other investments, so "spending" dino-juice carbon to enable everything else should usually come out a net gain, right?
• madaxe_again 8y ago
  This article talks as though Portland cement is the only cement. It isn’t. I’ve spent the past few years working in my free time on the restoration of several old buildings, under the guidance of my wife, who is a conservation mason, much of which has comprised removing cement and gypsum plaster and replacing them with lime mortar, lime plaster, and other lime products as appropriate. While it’s true that most lime products aren’t as strong as cement, and are permeable to water vapour, their CO2 impact is much, much smaller - and many applications which currently see the use of Portland could as easily use appropriate lime-based products. Breathability is a good thing in most structures - most damp that you see in buildings arises from impermeable materials and condensation. As to strength, lime-Portland blends exist which can create impermeable and strong concrete with less environmental footprint, and I’ve been experimenting with mixing lime with various different aggregates and plasticising agents - resulting in some interesting materials - ground pumice and slate in varying proportions produce very strong (high tensile and compressive properties) and impermeable materials - I was inspired by Roman concrete. Here’s a tiny bit of further info on CO2 footprints, from a company I’ve bought several tonnes of NHL from: http://ecolime.co.uk/c02-quick-facts/ http://ecolime.co.uk/c02-quick-facts/
  • NeedMoreTea 8y ago
    Roman concrete also has loads of advantages over modern concrete. Cracks don't spread, better salt resistance, and better earthquake resistance. Modern concrete will not survive like Roman examples have. With the environmental advantages too I'm surprised it hasn't had a resurgence.
    • rini17 8y ago
      Can't find the source now, the problem is that Roman concrete hardens slower than modern one.
      • saalweachter 8y ago
        That's also what killed Rosendale cement. ~1 month cures as opposed to putting a structure on the slab as little as ~1 day after pour.
• lpcam33 8y ago
  It's time to question economic growth. We cannot change the whole economy with a green one, we simply don't have the resources. This is just one example of many. What we need it's to take care of what we have right now and create conditions for people to have a good live regardless the economy is growing or not.
  • maxerickson 8y ago
    First step to creating conditions for 7 or 8 billion people to have good lives is to massively grow the economy.
    • FooHentai 8y ago
      Congrats you grew the economy. Now you have 16 billion people.
      • BaesRule 8y ago
        We see lower birth rates when countries grow richer. People have a lot more kids when there's a high chance a lot of their kids won't live long enough to support their parents in old age. Also in richer countries people aren't relying on their kids to support them in old age as much as in poorer countries.
        • quotemstr 8y ago
          No, FooHentai is right. We're screwed, Malthus-style, in the long run no matter what we do. The problem is that while modernism does tend to moderate fertility, it doesn't do so across the board. Some subgroups nevertheless have fertility far above replacement, and the exponential growth function tells us that these high-fertility groups will come to dominate the population. In other words, selection pressure ---biological, cultural, doesn't matter --- always wins in the end. Mother nature has the last laugh.
          • guntars 8y ago
• philipkglass 8y ago
  The report exposes quite the paradox: We desperately need these infrastructure projects to transition to a carbon-neutral world, but in doing so we will have to emit a massive amount of carbon. Massive compared to what? This article highlights that a single wind turbine uses a lot of concrete. But per the latest IPCC assessment, wind power over its life cycle already has the lowest median CO2 emissions of any electricity source. Sure, look for even cleaner ways to make materials, but this rhetoric is terrible. It lets fossil shills bludgeon you with your own words later: "see, environmentalists say coal burning emits massive amounts of carbon dioxide, but they say the same about switching to wind power, so there's no rush to change things." Here's a recent review article about curbing CO2 emissions from cement: Global strategies and potentials to curb CO2 emissions in cement industry https://s3.amazonaws.com/academia.edu.documents/39977040/1-s2.0-S0959652612006129-main.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&Expires=1530469511&Signature=iO7NNWFleA6%2F%2F8NF2ta4wIRigTA%3D&response-content-disposition=inline%3B%20filename%3DGlobal_strategies_and_potentials_to_curb.pdf https://s3.amazonaws.com/academia.edu.documents/39977040/1-s... It provides actual numbers and suggestions. Only half of cement's CO2 emissions per ton come from the chemistry inherent in calcining calcium carbonate to produce calcium oxide and carbon dioxide. The rest comes from the fossil sources of energy used to process materials. Like most industrial processes, it can cut emissions significantly just by switching input energy sources. Also, as someone else mentioned, concrete absorbs atmospheric CO2 as it cures. It's mostly the fossil combustion embedded in its production that drives emissions over its full life cycle.
  • philipkglass 8y ago
    As mchannon comments, concrete does not absorb a significant amount of CO2 as it cures. I was mistaken. The calcium in lime forms silicates. However, it remains true that half of the life cycle emissions of concrete come from fossil combustion. Replacing fossil combustion with other energy sources can cut concrete's CO2 footprint in half without any major changes in concrete's composition or use.
  • pstuart 8y ago
    If that CO2 is going up a flue it should be possible to capture (yes, more energy required).
• Pxtl 8y ago
  > The turbine will produce about three megawatts of energy on average which, when working at full capacity, is enough to power 2,400 U.S. homes for one month. Seriously, how does this kind of basic unit bungling happen in every report that involves Watts?
  • jacquesm 8y ago
    I spent a couple of years on a forum with renewable energy enthusiasts. In spite of endless corrections even there the posters kept messing that up so I have absolutely no confidence in journalism ever getting this right.
  • rdiddly 8y ago
    Unfortunately that's not the only blunder in that sentence. Are we talking "on average" or are we talking "at full capacity?" Not to mention the stylistic blunder by which a mathematical average, or a bunch of energy (or hey possibly even a turbine), is said to be "working at full capacity." I guess this is a dangling clause? Not sure if that's the right term for it. Shave off all the fur and you're left with a pretty good sentence: The turbine will produce about three megawatts of energy on average, which is enough to power 2,400 U.S. homes. (Assuming that figure is right.) It's shorter too.
    • rdiddly 8y ago
      Speaking of this kind of skepticism, 57 truckloads of concrete for one wind turbine seemed like an awful lot, so I did some rough math. Turns out 57 truckloads is probably right. Jesus. I assumed a pad-and-pedestal foundation where the pad is a cylinder 60'|18.3m dia. and 4'|1.2m thick, and the pedestal is also a cylinder but 20'|6m dia. and 4'|1.2m high. Total volume of both is about 465 yd³|355m³. Since the typical truck holds about 8 yd³|6m³, that's about 58 truckloads, which is surprisingly close to the 57 they stated. Each wind farm has a substation too, which will use some quantity of concrete for equipment pads. And some wind farms built in remote areas have to have their own transmission infrastructure built -- towers, with their own foundations, and switching substations, with again more equipment foundations. You could say concrete is the foundation of our economy... chortle chortle... groan... EDIT: added SI units for our rest-of-the-world pals
• pcmaffey 8y ago
  Hempcrete could replace a lot of non-load bearing applications. For anyone interested: https://en.wikipedia.org/wiki/Hempcrete https://en.wikipedia.org/wiki/Hempcrete
  • djrogers 8y ago
    There are tons of alternatives for non load bearing applications, that’s not really the problem.
• Lazare 8y ago
  I found the article odd, because it talked a lot about the different dynamics and the emissions of different things, but never netted them out. If you're going to talk about the CO2 emissions of the concrete needed for a wind turbine, the obvious next step would be to net them all out and figure out if building wind turbines is a net reduction in CO2 or not. The author seemed to go out of their way to imply that as long as we use Portland cement, it would not be a net reduction, but they never actually came out and said that. Not quite sure what to make of it. It's like reading an article that talks about electric cars and how high electricity can make them more expensive than you think, but then...never actually calculates their operating cost and compares it to a conventional ICE powertrain.
• deleted 8y ago
  [deleted]
• dmurray 8y ago
  > Cement is the second-most consumed material in the world, after water. This is repeated in the article but it doesn't sound right to me. Concrete is mostly stone and sand, with cement only making up 10-20% of the mixture. So both of those should be consumed more than cement is.
  • kleim 8y ago
    Interesting fact: there is actually a global sand shortage (https://www.independent.co.uk/news/long_reads/sand-shortage-world-how-deal-solve-issue-raw-materials-supplies-glass-electronics-concrete-a8093721.html https://www.independent.co.uk/news/long_reads/sand-shortage-...)
• fouc 8y ago
  https://en.wikipedia.org/wiki/Environmental_impact_of_concrete https://en.wikipedia.org/wiki/Environmental_impact_of_concre... Looks like it is the production of concrete materials that are generating CO2.
• scalablenotions 8y ago
  Let's see. Can you move your feet?