Ocean carbon removal is a new field in the carbon dioxide removal space but one that has enormous potential in restoring the climate and eliminating excess CO2 emissions from the atmosphere. Planetary Technologies, Inc. is a startup that is developing a process that takes inspiration from nature. It removes carbon emissions from the ocean through alkalinity enhancement, a process that rebalances carbon in the ocean.
We interviewed Mike Kelland, CEO of Planetary Technologies. He explained in detail what is ocean alkalinity enhancement, how the company’s approach accelerates the Earth’s natural thermostat and how the company plans to scale its technology to be able to remove gigatons of CO2 from the atmosphere annually.
Planetary Technologies is a young company, founded in 2019 but you have already contributed a lot to the voluntary carbon market. How did the company’s journey start? Why did you decide to take part in the project?
Our journey started back in 2018. I’m an entrepreneur by background in the software space and back then I sold my business and was trying to figure out what was next for me. I was mentoring a student at the time, Brock – who became one of the three co-founders of Planetary Technologies – and he was very passionate about climate change.
In 2018, the IPCC report came out which I found really interesting as I’m an environmentalist. I grew up canoeing and being in nature is a big part of who I am. As a result, we started digging into climate change and searching for a technology with a very high and direct impact on protecting the planet. We didn’t want to found a business that would only have a peripheral effect. We wanted to create a business that could be self-sustaining, led by a technology that was underappreciated and didn’t already have billions of dollars of investment.
Armed with these criteria, we spent about a year calling researchers around the world and asking about the technologies being developed. We ended up talking to many different people in all kinds of various interesting fields.
That eventually led us to meet with Dr. Greg Rau who had been working on ocean alkalinity enhancement (OAE) as a pioneer in the space. He is somebody who has published a lot of papers on the approach within the Lawrence Livermore National Laboratory.
He had pioneered a technology around mineral-based alkalinity enhancement in oceans for carbon removal, and he was actually looking for exactly the same thing as us. He was seeing that there wasn’t enough investment – OAE is a really high-impact potential climate solution and people were not really appreciating how important it could be.

We decided to give it a shot, so we founded Planetary Technologies in 2019. Now, we are moving forward in a way that is very focused and are taking on a leadership role within the emerging OAE space and ocean carbon removal. That’s where we are today.
What exactly is ocean alkalinity enhancement?
Ocean alkalinity is a natural process that the oceans have been doing for centuries and enhancement is simply a matter of accelerating this natural process. Essentially, ocean alkalinity acts as the Earth’s natural thermostat, yet one that is very slow. When we have higher levels of CO2 in the air, the ocean alkalinity process accelerates and when we have low CO2 in the air, it decelerates – it’s a moderating force.
The way it works is that when rain falls through the air it dissolves CO2 from the atmosphere, which slightly acidifies the rainwater. As rain falls it falls onto rocks that are naturally antacid, they react with the acidified rainwater and neutralize the acidity. The result of the reaction is the formation of a carbon-based salt – called a carbonate or bicarbonate – which ultimately accumulates in the ocean.

As a result, our oceans store the vast majority of carbon on the Earth’s surface. About 88% of the carbon on the surface of the Earth is locked in the chemistry of our oceans – this is a huge amount and carbon is a really important building block for the ocean’s chemistry. Anything that lives in the ocean makes use of these carbonate salts to form the structures of their bodies, including shells and bones – it’s a really important part of the ecosystem.
At Planetary, our technology speeds up that very natural geological process, in response to the increasing carbon emissions in the atmosphere. We are trying to make the pace of the ocean alkalinity process match the pace of human-caused CO2 emissions – which are much too high – by taking advantage of the different ways carbon gets into the ocean.
Due to the increased production of carbon emissions, we have more CO2 in the atmosphere. This means that more CO2 gets dissolved into the ocean, and due to this high volume, this CO2 is not neutralized. As a result, the ocean is becoming increasingly acidic.
Essentially, at Planetary Technologies we take rocks and pre-weather them so we end up with a pure antacid. When we introduce this antacid to seawater, we neutralize the CO2 dissolved in it, which reduces the concentration of CO2 in the ocean. As we do that, we enable more CO2 from the atmosphere to be stored safely in seawater.
This CO2 is stored in the ocean as a carbonate salt, where it will stay for about 100,000 years. This simple act of adding an antacid to seawater cleans up a lot of the extra CO2 that is acidifying the ocean.
How long does the natural process of ocean alkalinity take?

It’s a geological process, it works on geological time. If we stop all our emissions today, it will take hundreds of thousands of years for the natural process to take the CO2 in the atmosphere back to pre-industrial levels. It’s a really long process. We are able to speed it up to months thanks to our technology.
How does your process work? How do you add this antacid to the ocean?
We have taken a very specific approach; we work with a very pure form of antacid called magnesium hydroxide, which is already abundant within seawater.
We add this hydroxide to seawater through existing infrastructure, like wastewater facilities- at quantities under the levels outlined within existing permits. As magnesium hydroxide is widely used in wastewater operations, clear guidelines around its use are already in place. We work within this existing framework to ensure what we’re doing is safe and well understood.
When it comes to sourcing magnesium hydroxide, we look for low-cost material with a low environmental impact – the more carbon is generated during the production of the antacid, the less of a net carbon removal effect it can have. We also look for sources that are close to the coast and don’t require a lot of transportation. Within these criteria there is a fairly broad portfolio of existing and emerging sources that we can use.

The second thing that’s really important is safely adding the antacid through existing infrastructure. We have purpose-built systems, which include an integrated package of technologies – addition systems as well as monitoring and sensor systems – that allow us to always remain within the permit limits of the facility.
We have suites of sensor systems that are able to measure three different factors. One of them is the operational factor – how we operate these systems. Another is permitting factors – to make sure we are following each permit. And finally, MRV – measurement, reporting and verification. It is the final part, the measurement systems for determining the carbon uptake within the ocean which is probably the most complex.
When you conduct an ocean alkalinity enhancement process, you have to show that carbon has been taken out of the air and stored in the chemistry of the ocean as a result of your activity. But the ocean is really good at dilution and the alkaline materials Planetary Technologies use are very similar to the existing ocean chemistry – the process is safe but it’s also pretty hard to measure.
Some aspects can be measured before they go into the ocean like the neutralization of CO2. But some factors will ultimately need to be modeled, rather than measured within these systems.
The models are quite complex and also require a strong understanding of what the results mean to get an answer as to how much carbon you have actually taken out of the air over a period of time. This is a key part of the systems that we are building and developing.

Finally, it’s worth noting that our process is still in early-stage field trials and we will scale up only so far as science says it’s safe. We collaborate very closely with academic partners in order to scale up very responsibly and safely.
Do you work with other parties for the measurement and for the rest of this complex work?
Absolutely. MRV – measurement, reporting and verification – are three different things and Planetary Technologies only conducts the measurement aspect itself. Our systems and the way we work are designed to deliver a measurement. Ultimately, the verification is done by a third party, which reviews all of the results and the process and makes sure everything is very transparent. They provide to the registry, on which the credit will be issued, a report on how many credits should be issued, what’s been verified and how.
Within our systems, Planetary Technologies works very closely with a lot of different third parties. Verification is one piece, but we also work with regulators and communities – we are very transparent with communities around how our work is progressing.
Finally, we have close collaborations with academic institutions. These academic partnerships are really important as we develop this system and technology. It is very important that we have independent bodies that are very knowledgeable in the space and can help us define what is a safe level of application based on current academic understanding. There is a lot of third-party integration with everything we do.
Who is the company that verifies your carbon removal credits?
Isometric, a UK based company, is the verifier we’re working with today. They’ve just released their science platform where you can see an overview of our process. We are working actively with them to develop a verification protocol, and Isometric is undergoing an extensive scientific review in order to do that.
I associate ocean alkalinity enhancement with risks to marine life. Can you unravel any misconceptions and shed some light on what are the actual uncertainties and risks for the ocean when applying this method?
It’s a wonderful question and such an important one. Let me talk about a few different things right out of the gate. Marine carbon dioxide removal (mCDR) is a very broad term. One of the things that’s been really challenging and I think has caused people concerns about marine CDR is the method called ocean iron fertilization.
Ocean iron fertilization is an incredibly low scale potential CDR. Even if it was to work, the order of carbon removal is one to five gigatons a year as an absolute maximum. By contrast, the scale potential of ocean alkalinity enhancement that has been modeled out is about 100 gigatons of removal a year.
Ocean iron fertilization is also one of the first things that was tested in field trials and was not done particularly carefully. The issue is that ocean iron fertilization is used as the benchmark that we judge everything else against. It puts everybody in the wrong mentality around the different types of mCDR which are completely unrelated. The potential toxic effects of ocean iron fertilization have nothing to do with ocean alkalinity enhancement.

The risks of OAE are actually very different. One risk factor within OAE is the presence of trace metals. Some metals are toxic in aquatic environments. We always think of mercury and lead in that context and those are very real risks. But they are also incredibly manageable. We test every product we use in the ocean very carefully to see its exact trace metal content before using it. There are also well-established limits within the permits we work under concerning trace metals.
The second important piece is depending on the type of antacid that is used as they have variable levels of solubility – how fast it dissolves within seawater. There are three types of antacid (hydroxide) that you can use safely within seawater. One is sodium which is, which is massively abundant. The second one is calcium, there is an awful lot of calcium in seawater. The third one is magnesium – the third most common ion in seawater after sodium and chlorine.
Consequently, there are three different sources of alkalinity that you can use within our process – sodium hydroxide, calcium hydroxide, and magnesium hydroxide. Each has a solubility scale – for example sodium hydroxide is very soluble while magnesium hydroxide has very low solubility.
With magnesium hydroxide, our biggest concern, in terms of additions, is turbidity – essentially how much it clouds the ocean environment when it gets discharged in a local area. Magnesium hydroxide can produce a level of suspended solid which can form a shading effect – potentially slowing down the growth and photosynthesis of ocean plants. However, this is a transitory local effect and is a very manageable issue, we simply add at the level which is the limit for suspended solids.
Sodium hydroxide, because it is so soluble, has the potential to boost the pH of the local receiving area at a very high level very quickly. By contrast, magnesium hydroxide is safe by default, as it only dissolves and boosts pH at a safe level within seawater – when it boosts pH it stops dissolving – and calcium is somewhere in the middle.

A big part of our safety work centers on how much we change the local pH over what period of time, how much dissolution and distribution we are going to get before the pH changes and how much turbidity is going to be caused in the process. These are all things that are built into permits that we understand very well and the limits are well established.
To sum up, the primary risks are turbidity, pH, and metals. For the scale we are going to see in the foreseeable future, there is an incredibly high level of confidence that we are going to remain well within the limits, even in the local area.
Relevant: The State Of CDR Report Reveals Need For New Tech
The biggest challenge within OAE is going to be not safety but the measurability of the carbon removed by our activity because the materials we are using are so similar to the background of the ocean. There is a lot of research that is coming out right now with magnesium hydroxide saying that nothing happened when it got dissolved in the water.
Sodium hydroxide is the only thing we could use that would give us a high enough pH to see the impact on corals. Mainly because it makes corals grow faster since it neutralizes the CO2 that is in the ocean. Shellfish grow much better in more alkaline environments and our ocean is about 30% more acidic right now.
There have been trials in real ocean environments which saw a 7% increase in growth rates of corals only by pushing the pH up a little bit with sodium hydroxide. However, these were done in ankle-deep water – the only way they could actually get that much pH change. You would have to use a phenomenal amount of sodium hydroxide to achieve the same pH change within a normal ocean environment.

We are at the point now where we need to get out of the lab and get into small well-contained responsibly managed field trials to incrementally and very carefully scale up and see what the local impacts might be.
Sticking to the limitations and considering the difficulties of changing pH, is gigaton carbon removal via ocean of alkalinity enhancement possible then?
Yes, there is a report that came out earlier this year called The State Of CDR. Looking at the ranges there, they come up with an upper scale limit for ocean alkalinity enhancement of 100 gigatons per year. It’s by far the largest scale potential CDR that we have available to us.
Is that scale completely safe?
No scientist would tell you that it’s completely safe. We don’t know that. What we know is that at very small scales, it is safe. We have to go out and do field trials in order to see what is safe at larger scales, because we have done all we can at the lab to understand scale limits.
But to do this, we need to scale incrementally and do it safely with the appropriate tools to measure impact and track progress so we’re always being led by science. Only then can we incrementally go up to a gigaton scale in a responsible manner.
You published in February your own Measurement Reporting and Verification Protocol for ocean carbon removal for public consultation. Did you get some useful input and how did that help you further the methodology?
Yes, we did. And we did get some useful feedback which was really good. The other thing we received were some interesting collaborations – people came in saying they want to work with us on the approach. I think it really helped the whole field.
What Planetary Technologies is trying to do as a company, is to support the whole OAE field and make it a successful pathway for CDR because the scale potential is so high. We will continue to learn more as we do the small incremental scale ups but what we’ve seen so far is looking very promising.

Could you share more details about the pilot projects of Planetary Technologies and these small-scale field trials you are planning? How are you going to reach a gigaton scale of removal?
Gigaton scale is a long way away. We have two projects today that we have published on our website where we’re actively engaging with the community and regulators. Neither project has started yet, we are still working through these processes right now.
One is in Hayle, Cornwall, in the UK and the other one is in Halifax, Nova Scotia, in Canada. The way that we do our projects today is we work very closely with a local academic institution. In the UK, we are working with Plymouth Marine Lab Applications and in Halifax with Dalhousie University. Both are very strong organizations with world leading expertise in this area.
We also direct a lot of the research that should progress within the context of these projects. We see ourselves as a catalyst, the ones who are proposing the project and pushing things forward. We also have a lot of the control over how the project progresses to ensure it’s done in a way that independent scientists believe is safe and well-validated.

Ultimately, how I expect a gigaton level of carbon removal to work, is having relatively small-scale additions at a huge number of sites around the world. The reason for that is, it reduces risk over time.
You can’t increase the pH of the entire ocean by a couple of decimal points all at once, it’s not feasible. However, if you could, you would have a massive impact on climate with zero risk. So, you can manage most of the concerns and risks at a local level. Doing very safe small additions at a huge number of places is how you really radically reduce risk across the board and over time.
Can you reveal your price of a ton of CO2 removed?
This is something we are progressing very rapidly. What I would say is that all of our modeling, and the work we have done so far, is showing that our price per ton of carbon removal at scale is going to be well under $100.
Depending on a few things we are working on, it’s likely to be under $25 a ton. For permanent carbon removal, we think it’s not only one of the most scalable technologies but also potentially one of the cheapest.