One other Day, One other Suspect Ocean Carbon Seize Technology – Insta News Hub

Join daily news updates from CleanTechnica on e-mail. Or follow us on Google News!

Carbon seize is again on the hype cycle, years after it was final being pushed upon us as the one actual answer to our local weather change downside as a result of <insert cause to delay actual motion right here>. It’s a favourite of the fossil gasoline trade for apparent causes. A few of them are even saying the quiet half out loud, that it offers them the social license to not solely proceed to function, however to really improve extraction of coal, oil, and fuel.

In the meantime, the local weather disaster is heating up. For the primary time, recorded temperatures for the world for the previous 12 months averaged 1.5° Celsius greater than the pre-industrial reference interval. Naturally, extra excessive climate, extra floods, extra fires, extra warmth waves.

Into this fraught atmosphere crammed with wealthy particular curiosity teams dealing with the warmth deaths of their enterprise fashions and individuals who actually try to do the perfect factor doable comes extra oceanic geoengineering. I’d seemed on the idea of geoengineering reasonably carefully years in the past and concluded that if we needed to do photo voltaic geoengineering, we’d have misplaced the battle. Creating the next albedo for the earth would scale back atmospheric temperatures, however it wouldn’t deal with the foundation causes and it wouldn’t do something for the opposite signs of them.

And one of many main signs I used to be involved about was what’s known as oceanic acidification. The diagram above illustrates the issue. Carbon dioxide is absorbed the ocean and turns into carbonic acid, therefore acidification. But it surely actually simply makes the ocean rather less alkaline. That’s really in a roundabout way having any vital results past barely decreasing the power of the ocean to soak up carbon dioxide, decreasing its effectiveness as a carbon sink.

No, it’s what occurs with carbonic acid that’s the issue. It grabs carbonate ions and makes bicarbonate ions out of them. One carbon atom from the carbon dioxide grabs one other carbon atom from the carbonate ion and makes two bicarbonate ions.

And shellfish want the carbonate ions to construct their shells. No carbonate ions, no shells.

I’ve been on a little bit of a jag assessing purported ocean carbon drawdown options and to date I’m not impressed. First up was Planetary Technologies, which was shaped across the concept of dumping milk of magnesia — magnesium hydroxide — within the ocean to bind with the carbonic acid. That really had benefit for the shellfish, however as a carbon drawdown answer, it was lifeless within the water.

Keep in mind that the slight acidification lowered carbon dioxide replace. Magnesium hydroxide bonds with the carbonic acid to make magnesium carbonate and will increase alkalinity, enhancing carbon dioxide replace potential a bit and never blocking carbonate ions that shellfish want. However magnesium hydroxide prices tons of of {dollars} per ton, enhances oceanic uptake solely a bit greater than a ton of the product, and has a carbon debt of producing that’s properly above any carbon dioxide uptake advantages. Robbing Peter to pay Paul doesn’t scale except you discovered a faith and your identify is Paul.

Then I checked out Captura, which reverses the method, breaking up bicarbonates and carbonate ions electrochemically to create gaseous carbon dioxide. Eradicating carbon from the massive carbon sink with the intention to create gaseous carbon dioxide that must be resequestered is a little bit of a headscratcher. Particularly while you do the mathematics and understand that it might take billions of tons of seawater to get one million tons of carbon dioxide. Simply lifting the required seawater for one million tons of carbon dioxide about 5 meters — from beneath low tide degree to an onshore processing facility — would require about as a lot electrical energy as can be required for 4 million US houses. Simply utilizing the electrical energy to decarbonize the grid would keep away from at minimal 17 instances the carbon dioxide emissions as is perhaps captured by the Captura answer. The answer possible additionally has vital membrane issues that they are going to discover very difficult to beat.

Chip in a number of {dollars} a month to help support independent cleantech coverage that helps to speed up the cleantech revolution!

And now a contact has pointed me at Equatic, one other California answer. There should be one thing within the water down within the Golden State. All three of the companies have roots there, with Planetary’s CTO being a California professor and Captura and Equatic being based out of California universities.

What does Equatic do? It takes carbon dioxide from someplace, in order that must be captured by another course of. Then it sucks seawater out of the ocean and mixes the carbon dioxide with it. Then it makes use of a little bit of electrical energy to mess with the electrochemistry.

Then the carbon dioxide to carbonic acid course of that scoops up carbonate and calcium ions together with different ions is accelerated so much and the water turns into heavy with secure bicarbonate ions. Then this carbonate and calcium ion depleted water is returned to the ocean.

In the event you’ve been following alongside, at this level you’ll be asking a query: However what concerning the shellfish? That’s a very good query which nobody appears to be asking the Equatic folks. No, they’re getting glowing press as a result of their course of goes to be piloted in Singapore with a tiny plant that may take away 100 kilograms of carbon dioxide per day and produce a little bit of low carbon hydrogen within the course of, assuming it was run on inexperienced electrical energy.

Sure, electrolyzing water produces hydrogen. Who knew?

The plant principally is a special hydrogen electrolysis expertise that can produce 300 kilograms of hydrogen when a bunch of seawater is blended with the carbon dioxide. How a lot seawater? Effectively, their most recent published paper asserts that they are going to sequester about 4.6 kilograms of carbon dioxide per cubic meter of of seawater processed. A cubic meter weighs a metric ton, so sequestering a ton of carbon dioxide requires about 217 tons of seawater. That ratio is an order of magnitude higher than Captura’s course of, so the electrical energy required only for pumping the water might be solely adequate to energy 400,000 houses for a 12 months and nonetheless gained’t break even on simply utilizing inexperienced electrical energy to inexperienced the grid as an alternative.

However you do get inexperienced hydrogen out of it, so there’s an upside. Scaling their answer to one million tons of carbon dioxide a 12 months would require 273 instances extra of all the things per day. 100 kilograms of carbon dioxide turns into 27 tons of carbon dioxide per day, 82 tons of hydrogen a day, and 60 tons of sea water a day.

However what concerning the shellfish?

The identical downside Captura has exists with this answer. It depletes the carbonate ions that shellfish require, however it’s extra environment friendly at it. The diffusion downside which might see Captura sucking in carbonate and bicarbonate depleted water for diminishing returns can be amplified right here.

So this is able to require much more cautious siting for vital lateral flows of sea water, sideshore currents, with the intention to keep away from diminishing returns and watch out to not be sited anyplace the place there have been shellfish beds of any significance downstream.

However absolutely this downside ought to be entrance and middle for the scientists and advisors of Equatic? Certainly they’ve a biologist on employees? Apparently not.

The newest paper has a piece on the consequences on seawater chemistry, however completely nothing concerning the implications of these modifications. No article or examine I’ve been capable of finding signifies that they’re fascinated by this in any respect.

In fact, I could possibly be fallacious. I’m not a marine biologist or an professional in shell formation amongst mollusks and crustaceans, I’m merely studying extremely credible sources and looking out on the fundamental chemistry concerned in each the carbon seize options and shellfish shell formation and drawing a line between two very carefully adjoining dots.

Equatic seems to keep away from among the Captura traps, particularly by avoiding membranes and decreasing the amount of water required for the method. And their carbon dioxide feed doesn’t should be good, with even 30% carbon dioxide by quantity being satisfactory for the method to carry out. They usually get precious hydrogen out, identical to the chloralkali course of they talk about for comparability, one I checked out associated to the one hydrogen for power play I’ve analyzed that is smart, Teralta’s diversion of waste hydrogen to keep away from burning pure fuel at a close-by pulp and paper mill.

The method, if I’m studying the mass power balances and paper proper, reduces the electrical energy required for electrolysis by altering the alkalinity with carbon dioxide. Principally, they’re buying and selling pumping plenty of seawater and carbon dioxide for lowered electrical energy prices, which signifies that they’re very delicate to the value of carbon dioxide, simply as artificial fuels are.

I’m left with vital crimson flags. Their course of answer shall be topic to all the identical fouling as something which runs a whole lot of seawater by means of it, so shall be larger relatively than decrease upkeep. Their carbon dioxide stream must be from a supply that doesn’t introduce a whole lot of different undesirable contaminants, so whereas it doesn’t must be pure, it has some vital limitations. It must be low cost too. And the method accelerates the method of taking shellfish-required chemical compounds out of seawater.