One other Day, One other Nonsensical Oceanic Carbon Seize Non-Answer, This Time Italian – CleanTechnica – Uplaza

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Common readers may assume Californians have a lock on poorly thought-through concepts for ‘enhancing’ oceanic carbon uptake, however apparently Italy determined to throw a go browsing this hearth. A startup is selling the thought of digging up long-sequestered carbon dioxide within the type of limestone to make quicklime to make bicarbonates to pour into the ocean. There’s a bit to unpack there.

Let’s begin with the fundamentals. Heating limestone at 900° Celsius to make quicklime is a basic course of within the manufacturing of cement. It’s a significant local weather change downside as the method produces about 8% of world carbon dioxide emissions. This can be a very effectively understood chemical and industrial course of that innumerable persons are working to discover a approach round that doesn’t contain going again to residing in mud huts.

Fortunately, there’s a stable set of options for the issue that’s going to handle most of it, and many of the options are already effectively underway globally. This chart is from my projection from earlier this yr of cement displacements and decarbonization pathways by means of 2100. An enormous one, lowered demand, is roiling markets already, as China’s large infrastructure build-out — 500 cities, 45,000 km of high-speed electrified rail, 177,000 km of highways, 40 or so main ports, and so on. — is coming to an finish, and with it a decline in metal and cement demand, together with the power required to fabricate them.

As I stated to an Indian utilities skilled final week whereas giving one of many final of my seminars on world decarbonization levers with a masala taste, this one on carbon seize, utilization, and storage, China has been manufacturing half of the metal and cement used globally, ten instances greater than India. If India, Brazil, and Indonesia every double metal manufacturing, they gained’t change China’s reductions. Additional, they aren’t industrializing in the way in which that China did, with completely different financial development trajectories that aren’t as carbon heavy and in addition aren’t as quick. China’s discount will likely be eradicating an enormous emissions downside that gained’t get replaced.

Cross-laminated timber (CLT) or mass timber or engineered timber or regional variants like Xlam is simply beams, partitions, and flooring fabricated from plywood, massively stronger, lighter, and lower-carbon than bolstered concrete, and it truly sequesters a ton of carbon dioxide in a ton of the stuff. Geopolymers and epoxies are cement replacements, generally a bit higher and generally quite a bit higher. Geopolymers additionally eliminate waste streams from different industrial processes, which is useful. Software program efficiencies means constructing extra with much less cement. Recycling outdated concrete into new cement has play, particularly within the US the place it might displace a 3rd of demand. In fact, the top of inhabitants development, arriving between 2050 and 2070, means no new folks requiring residences and extra reuse of present buildings. That is additionally one of many few domains the place carbon seize may pencil out, particularly with electrified processes in cement vegetation beside sequestration websites.

However this may all include an enormous decline in digging up limestone and baking it. That’s an enormous environmental win.

Shifting on from the issue that’s digging up and baking limestone right this moment, let’s discuss briefly about different oceanic carbon drawdown options. I’ve been this downside for a number of years, working my approach by means of the chemistries and considerations, and extra not too long ago digging my approach by means of the proposed options. It’s price that chemistry, and why oceanic acidification is an enormous concern that’s not mentioned practically sufficient as a local weather change affect.

This diagram from the NOAA spells out it pretty properly, however is kind of obtuse in regards to the implications. Carbon dioxide will get absorbed by the ocean. It combines with seawater to make carbonic acid, which reduces the alkalinity of the brine a bit. Then it combines to free-floating carbonate ions which have a carbon atom in them to make a few bicarbonate ions, which is the shape 98% of oceanic carbon sits in.

The discount in alkalinity is a matter as a result of it reduces carbon dioxide uptake by the oceans, and so they usually suck up 25% to 35% of our extra. The extra carbon dioxide we emit, the much less the oceans can suck up. That’s the primary, however not the one downside.

The second downside is said to these carbonate ions. Shellfish use carbonate ions to make their shells, however can’t use bicarbonate ions. As carbon dioxide goes by means of the method of creating bicarbonate ions, it reduces the accessible carbonate ions. Fewer carbonate ions, extra brittle shells. That’s an enormous downside for the entire sea life that builds shells and reefs, and it’s an enormous downside for all the things that is dependent upon them for energy. You already know, like humanity. About 17% of humanity’s protein necessities are met by seafood, and seafood is dependent upon shellfish present, straight or not directly.

As a word, this is among the causes I’m leery about photo voltaic geoengineering, because it slaps a bandaid on one downside, heating, whereas doing precisely nothing for the opposite downside, oceanic acidification. As a result of it might put a bandaid on a symptom which is extra apparent to us, heatwaves getting headlines and all, and doesn’t assist an issue which is invisible to us, the issue that’s invisible to us would worsen and we wouldn’t do a lot about it.

Scientists have been conscious of this and dealing on options for many years, and not too long ago that’s resulted in a spate of remarkably poorly thought-through startups. One among them gained the Musk-sponsored carbon drawdown XPRIZE price one million {dollars} with a scheme to dump magnesium hydroxide — milk of magnesia as most individuals comprehend it — into oceans regardless of having a carbon debt for the magnesium hydroxide that swamps the carbon advantages, in addition to a price that was considerably eye-watering. One other proposes to mine, crush, and ship inexperienced, spiky olivine to seashores, ignoring once more the prices and carbon debt, in addition to the social license to show seashores that may pay for sand replenishment into inhospitable and odd-looking inexperienced margins. One other proposes to raise billions of tons seawater probably 5 meters at nice energetic expense, electrolyze it into submission, suck out the carbon dioxide and pump the seawater again into the ocean, leaving the query of what to do with the ensuing tens of millions of tons of fuel. One other is doing considerably the reverse, utilizing carbon dioxide, seawater, and electrolysis to fabricate bicarbonate ions and a little bit of hydrogen, additionally requiring large power and benefiting from the carbon seize and hydrogen hype cycles.

Together, it’s very troublesome to think about any of those options scaling or getting remotely cheap per ton of carbon dioxide sequestered, the place they really handle to have web destructive carbon dioxide within the first place. A few of them make the shellfish downside worse, but marine biologists don’t seem on their rosters. I think a number of failed environmental affect assessments of their future. The one resolution that has some benefit is the one which proposes to raise billions of tons of seawater to the seashore to electrolyze it, and the power necessities make it clear that it’s like all carbon seize options, one thing that might take helpful low carbon electrical energy out of locations the place it’s truly delivering low-carbon options and avoiding carbon dioxide emissions within the first place. As famous, all of those companies have California roots. One imagines that the proportion of surfers is excessive.

Into this unlucky group of non-solutions and the context for cement comes the Italian entrant. They’re proposing that as an alternative of avoiding digging up and baking limestone, that we do extra of it. Their full course of includes burning biomass in pure-ish oxygen to create warmth and a stream of carbon dioxide to seize. The warmth would bake the limestone, creating extra carbon dioxide and quicklime, aka calcium carbonate. They’d then mix the quicklime and carbon dioxide of their reactor with seawater to fabricate a slurry that’s wealthy in calcium bicarbonate ions.

On their web site, the PDF they ship round and at the very least within the summary and conclusions of the scientific paper that they base this on — the total paper is firewalled, as is so continuously the case — they’re silent on the query of whether or not their course of would suck carbonate ions out of the seawater.

In web, they wish to burn biomass, which they get from someplace, in pure oxygen, which has a carbon debt of 0.4 to 1.2 tons of carbon dioxide per ton of oxygen throughout the first processes of cryogenic air separation or strain swing adsorption. They wish to dig up limestone at energetic and carbon debt expense. They wish to use the warmth from burning the biomass to unsequester already completely saved carbon dioxide, creating extra carbon dioxide. They then wish to pump seawater up at energetic expense to combine with the quicklime and carbon dioxide to perhaps cut back the carbonate ions shellfish require and requester the beforehand sequestered carbon dioxide in addition to some biomass carbon dioxide.

If this looks like energetic and carbon nonsense, with a aspect serving to of potential opposed sea life impacts, it’s. The publication historical past of the lecturers who’re behind this make it clear that their hearts are in the best locations, as are the hearts of the lecturers behind the milk of magnesium, sea water pumping, and inexperienced seashores schemes. However digging up extra limestone to unlock its carbon dioxide to relock it within the oceans may make sense solely when we’ve stopped digging up limestone to show it into unabated cement, and provided that the method doesn’t mess with shellfish. Mess with shellfish, and also you mess with humanity’s meals provide.