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Launch HN: Heimdal (YC S21) – Carbon neutral cement

news.ycombinator.com

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Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#71

Post by marcuslima »

lifekaizen wrote: post #42
nobodyknowsyoda wrote: post #15

Earlier quoted context omitted.

What is the current price of carbon credits in the ETS? I am from the USA / am dumb, so don’t know how to find it Also good read for everyone: https://www.gatesnotes.com/Energy/Introducing-the-Green-Prem...

The World Bank has a great resource here which lists out pricing for emissions trading systems (ETS) and carbon tax by country.[0] (Map & Data > Price > Type of Instrument). Highest carbon taxes are $100+ / ton (Sweden, Switzerland, Lichenstein), high initial value for trade is about $50 (EU, Switzerland). We are a bit behind in the US in credits or taxes, we are now treating the social cost at $51, but not using tha…

That estimate of cost to society should tell us something when contrasted with the actual prices being levied right now. Hopefully we'll get closer to that number eventually!

Hopefully the US does this: https://news.climate.columbia.edu/2021/05/06/proposed-45q-ta...

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#72

Post by marcuslima »

LeifCarrotson wrote: post #66
marcuslima wrote: post #35

Earlier quoted context omitted.

The calcium all comes from dissolved calcium bicarbonate - we trigger precipitation by shifting bicarbonate to carbonate ions, which are insoluble. Essentially we acceelrate the oceanic carbonate cycle

I understand that calcium salts and bicarbonate ions are common in the ocean, and are increasingly common as the oceans become more acidic, but have no idea how common that is. How much seawater do you need to get one kg of CaCO3 precipitate?

We're actually working on figuring this out. Our current calculations assume we need to process a huge amount of seawater (11,000 tonnes per tonne of CO2), if the CO2 is the limiting factor (2000 umol). However our R&D suggests undersaturated seawater re-absorbs CO2 from the air surprisingly quickly. Might be able to get this 10x lower

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#73

Post by LeifCarrotson »

rout39574 wrote: post #43
marcuslima wrote: post #13

Earlier quoted context omitted.

Our current cost per tonne is in the same order of magnitude when including the carbon value from the European ETS. The key success criteria for making large plants profitable will be connecting to cheap electricity at <$50/MWh we're in the black

What electricity sources have you identified as acceptable for this? Proximity of e.g. hydro to an ocean seems like a small set of sites. :) A naive glance suggests that solar capacity factor of 25% is going to put that particular source out of your budget.

One fortunate aspect of electricity is that it's easy and efficient - on the order of 2-6% losses due to transmission for hundreds of miles - to transport.

Whether your country has invested in renewable sources like hydro plants and associated high-voltage, long-distance transmission lines is what matters. The geography of whether hydro plant is near the coast or not is of less importance than whether it exists or not!

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#74

Post by brilee »

marcuslima wrote: post #53
brilee wrote: post #49

I'm not sure I understand where the carbon savings comes from. The cement industry specifically needs lime, CaO. Lime is most easily obtained by burning CO2 off of limestone, CaCO3. As you point out, this is effectively "burning off" captured carbon dioxide and is bad. Where does the carbon savings come from when the ultimate destination is to just burn CO2 off and make the actual desired product, CaO? Is this proces…

Yep, exactly! The world needs CaO for cement. We have a carbon neutral process for making it. It's actually overall negative as not all carbonates we extract are usable in cement production. But as far as cement producers are concerned it's carbon neutral.

A followup question... how do you regenerate the alkaline sorbent? It gets acidified in the process of extracting CaO from the water and needs to be made alkaline again somehow.

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#75

Post by marcuslima »

noahth wrote: post #58

This sounds really cool, and I hope it goes well. We need to work every angle we can to address climate change, and test as many ideas as necessary to get there. My issue with this post is the claim that you will be making the world's first carbon-neutral houses. I understand the need for strong exciting marketing language, but, surely you mean something like, first modern Western-style carbon-neutral houses.

Thanks! Yes that's absolutely true, that could've been more specific. In the modern world almost every house needs concrete for something, at a minimum for the foundations.

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#76

Post by skohan »

marcuslima wrote: post #68
skohan wrote: post #54

Very cool project! A couple questions: 1. How does your synthetic limestone compare to natural limestone? Are there any important performance differences in terms of the material properties of the resulting concrete? 2. What are the biggest bottlenecks/obstacles in terms of scaling this to the point it could replace a significant portion of natural limestone used today? Edit: do you have any blog posts/more informati…

Thanks! 1. We are entering the product testing stage with our cement producing parnters in the next few months, so I'll have a better answer for you then. But from a chemical composition point of view, our product is purer than mined limestone and so should perform better. 2. Biggest bottleneck from our perspective is nailing planning permission to build our plants quickly enough to supply cement producers. Unfortuna…

Yeah cool! If you have a twitter or any other way to follow you guys I would love to - I work at a sustainability-focused startup and I know a lot of people who would be interested in this, and not all of them would be in the HN audience.

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#77

Post by mikob »

Sounds promising! I have noticed companies with environmental impact have disproportionately more success in crowd-funding. Many non-institutional investors (like myself) put their money in ideas that are good for the world - almost like charity. Perhaps you will consider raising funds and spreading the word using a crowd-funding site such as https://www.startengine.com/explore

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#78

Post by marcuslima »

pierre wrote: post #57

I would love to see you success! Do you have more technical details on your process? Did you publish anything? I try to dig more on your website but the content is rather thin (I learn more about what you are doing by reading your post here). What are the by product? You mention cement and drinkable water, but there should be other byproduct to handle such as brime?

Thanks a lot for that! We have very little published at the minute for patent reasons. It's actually pretty neat as we consume the waste brine in the process, so nothing to disturb local marine life as you have issues with at reverse osmosis desalination plants

Re: Launch HN: Heimdal (YC S21) – Carbon neutral cement

#80

Post by marcuslima »

comex wrote: post #46

What’s the greatest challenge or limitation, technology- or business-wise, that your startup faces? If it fails, why will it fail?

Honestly, our biggest problem right now is moving quickly. In the next 6 months our biggest problem will be getting planning permission to stick large pipes into the sea to process large amounts of seawater ;) We don't discharge anything but seawater undersatured with CO2 so we're not negtaively impacting the surroundings. But government is slow with these things
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