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chasil

This doesn't seem practical.

https://pyrofarms.com/blogs/pyrofarms-blue-light-special/alg...

"When used in bioreactors, algae is 400 times more efficient than a tree at removing CO2 from the atmosphere."

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>When used in bioreactors*

When used in a sealed climate-controlled chamber that produces the ideal conditions on land for an aquatic plant specie.

IIRC it's ridiculously expensive to scale algae bioreactors, while trees grow and maintain themselves. I wish algae was easier to scale because it does have great potential.

Why don't we just scale them in the oceans?

That might disturb the ocean ecosystem.

And these trees don't?

I think the larger point is that there isn't a simple, obvious, "Why don't we just do XYZ?" solution to the problems being discussed here.

I agree anything we do at scale will affect the ecosystem. However, restoring an ecosystem to a previous state seems less risky than changing oceans to a new state.

Maintaining things sitting in the ocean is still expensive. You can’t send robots out, you must send humans.

Oil rigs are worthwhile just because they can be turned on/off relatively easily depending on market conditions and when they are on, they mint so much money that expensive humans are a rounding error.

Why can't you send robots out?

There are plans to add (I believe) iron oxide to the oceans to increase algae growth. Don't recall the organization's name right now.

I hope not. You can permanently alter (i.e. for decades) the climate in a region by creating an algae bloom.

Out of curiosity, what are the challenges in scaling algae bioreactors?

They're easy to scale in some sense (just make a bunch of small ones), but small reactors have a high surface area to volume ratio -- i.e., a high expense to algae ratio. Making bigger vats is problematic because the work being done is proportional to surface area (light penetration) and because the chance of infection goes up exponentially.

Algae also produce waste that SMELLS. Now you have costs to deal with that, which also reduces _where_ you can put them, since most people don’t necessarily enjoy living near the smell of a wetland.

Then there are the ocean-based startups trying to just assist with what nature does out in nature. Also tough to scale when dealing with dropping structures in the ocean and making sure they work with as little maintenance as possible.

So both indoor “Ideal condition” and outdoor “Ideal condition” growing are actually really tough to scale cost effectively. Doing something _else_ with them while sequestering carbon could be interesting though. I know one team that is using algae to clean up wastewater wile producing electricity. I don’t think they’ll get to cost effective scale, but I think the idea tackles two great problems at once in a creative way, and that’s still progress!

My startup is working on novel microalgae photobioreactors - we are raising an angel/pre-seed round right now.

Our system is far more energy and space efficient compared to PBRs and raceways - we do this via a proprietary mechanism that greatly increases surface area to volume ratio of liquid water in our reactors. Feel free to drop us a line at info[at]skyfarmclimate.tech

I used to be on a research project that attempted to do this with a fungus/algae mix because when grown together the fungus suspended the algae throughout the column of water. That was a fun project that had it's funding pulled, and then I had to get into software engineering to make a living. What's the basic way of accomplishing your improvement?

I can share further details by email, but the gist is we enable much faster gas exchange for microalgae cells compared to existing systems, inside a unique reactor design that gives us some other benefits for common cultivation processes.

What do you dto with the algae after it has grown?

Sell it

Are you by chance growing spirulina algae? It's a popular supplement.

Not at the moment - but it is an option for the future. Technically it is a cyanobacteria not microalgae

Technically both…

Your website makes it sound like you're growing algae for co2 capture, but if you're selling it and not sequestering it then what's the point?

We're selling it as biochar, sorry should have specified.

Weird. So you are supposedly beating everyone in terms of yields and yet focus on producing something worth even less than protein per kg. Wouldn't it make more sense to cream off the market on higher value-added products before scaling up while expanding into increasingly low value products?

if you're trying to sequester carbon.. bury it. anything else will allow it to be released back into the atmosphere anyway

I once read a comment from an expert in that field who said that it was essentially impossible to prevent contamination, and that they had to constantly test and then shut down and sanitize when they discovered a different species of algae in their system.

How do you mitigate that issue? (And good news if you have a solution, that same person said they figured whoever solved that problem would be the world's first trillionaire).

Mitigation strategies are varied, you basically cannot guarantee there will not be any contamination if you are doing any kind of scale. We are looking at polycultures/consortiums (robust ecosystems inside one reactor), various filtration systems and high frequency monitoring. There are some others we won't publish (yet)

It seems indeed rather futile to plant trees for carbon sequestration. Depends on the exact situation, but simply put trees are often almost carbon neutral and at a fairly smale timescale (e.g. [1]) and even if they weren't we'd need a lot of them (e.g. [2]). To the point one starts to wonder whether these so-called 'climate trees' (a term commonly used by some groups in my area) isn't just a product of lobby groups and/or people who don't know a lot about biology or ecosystems. A tree is of course a perfect 'climate excuse': easy to plant a tree, easy to think you're doing something for the climate.

Now, the part about needing a lot of them is also true for these bioreactors. Still doesn't seem super practical. Nor is the storage or use of all that captured carbon? I mean in theory this is great, but practically it's a bit hard to tell if this is doable technologically.

On the other hand there are things which are (purely technically) easier to achieve and more efficient, like wetlands and peatlands (and that also goes for peat forrests, so yes trees) e.g. [3] The numbers are so huge that trying to make sure they don't degrade or aren't converted into farmland or sucked dry and trying to (re)create them by introducing or restoring wetlands to their original form, this seems like something which is actually worth it. I'm not saying it's the only thing to do, I'm aware such land isn't super popular nor practically useful, and maybe I'm missing something else, but it really looks like if you have the choice to either go plant trees somewhere or somehow try to protect peatland, the latter wins when it comes to sequestration.

[1] https://dspace.stir.ac.uk/bitstream/1893/31440/1/gcb.15229.p... [2] https://climate.mit.edu/ask-mit/how-many-new-trees-would-we-... [3] https://www.iucn.org/resources/issues-brief/peatlands-and-cl...

> It seems indeed rather futile to plant trees for carbon sequestration. Depends on the exact situation, but simply put trees are often almost carbon neutral and at a fairly smale timescale

I'd say this is losing the forest for the trees. An individual tree doesn't matter, what matters is a durable ecosystem. Say a square kilometer of denuded farmland is converted to forest. Thousands of tons of carbon will remain in the plants, animals, fungi, microorganisms and soil as long as the forest stands though the individuals will die. It could be there 10 years or 10,000 years, depends on how long the ecosystem is maintained.

> Say a square kilometer of denuded farmland is converted to forest.

In principle I'd agree, but: again this really depends on soil type and history and surroundings and type of forrest. The forrest won't be bad, but depending on factors as far as sequestration goes (and biodiversity as well to some extent) it could actually be better to turn the farmland into a meadow. Those don't necessarily have to be wetlands to sequester more carbon over the course of years. Just like for every new square kilometer converted to whatever, it might actually be worth more to try and preserve one square kilometer of rainforrest instead of having it cut down.

interesting point, I've read somewhere that from biodiversity, and carbon sequestration viewpoint some forests (corniferous, like taiga) are much poorer than grass steppes. It was argued that mammoths were important because they were strong enough to fall down trees, making space for grass to grow.

Isnt it funny when you finally realize HN's had you on mute for months. ;)

How is the CO2 sequestered? That is conspicuously missing from that marketing blog post.

In nature, the dying algae fall to the sea floor, and sequester the carbon there.

An easy stimulant to this process is to dump powdered iron into an algal bloom.

https://en.m.wikipedia.org/wiki/Iron_fertilization

I'd be interested to know more about the carbon cost of production for the powdered iron. I assume you could use scrap metal for this purpose, but scrap metal is already pretty recyclable as I understand it.

I don't think pure iron would work because it's not soluble - what people use are iron sulfates which are minerals that occur naturally.

Ferrous sulphate is available below $100 / ton and seems to already be used in large quantities for wastewater treatment. Doesn't seem hard to source if the same stuff will work for algae.

Okay neat— the WP page for it mentions it being produced at least in part as a byproduct of steel production:

"In the finishing of steel prior to plating or coating, the steel sheet or rod is passed through pickling baths of sulfuric acid. This treatment produces large quantities of iron(II) sulfate as a by-product."

https://en.wikipedia.org/wiki/Iron%28II%29_sulfate#Productio...

So I guess that explains why it's so inexpensive, but of course as with many such things (natural gas from oil production, whey from yogurt/cheese production, etc), once there's a robust market for the "byproduct", it can result in changing the original economics.

However, you run the risk of advantaging algae that produce high levels of toxin. Even non-toxic algae starts to do this when concentrated. Since iron fertilization only works far offshore, a lot of our industry has to hope that bloom doesn’t enter the food chain.

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