From Pilots to Pioneers: Marine Carbon Removals Making Waves

Note: the views expressed in this article are my own, and don’t reflect those of my employer. I’ve attempted to list some of the recent announcements in marine CDR — realizing it will inevitably be non-exhaustive. If you’d like to add something, or if you have any comments, feel free to reach out through the comments below or at lennart@co2outoftheblue.com, I intend to update this article with additional input.

When I started my journey in carbon management during my PhD, back in 2012, it was fairly easy to keep track of what was happening. At the time, point-source CCS capacity was actually decreasing, and carbon dioxide removals (CDR) were still considered more of a theoretical exercise than a real option.

My TEDx talk in 2014 — how times have changed.

This has changed dramatically over the past couple of years, and feels like it’s still accelerating, making it difficult to see the forest through the trees. Not a day goes by without someone forwarding me an article on carbon technologies with an ask for commentary.

One swallow does not a summer make.

Yet, an unmistakable trend that jumped out to me recently, is the acceleration of developments in marine-CDR ecosystem. A couple of years ago, ocean-based CDR was limited to a handful of aspirational announcements. Today, there are profound developments in all facets of the field. For my own reference, and for your convenience, I’ve made a list of what I’ve been reading in 2023.

Here is an overview of the sections:

1. The solution seascape (what is marine CDR?)
2. Plenty of fish in the sea (who is doing this?)
3. Diving into the demand (who is buying that?)
4. Regulatory tides, rising support (who is backing it?)
5. A deluge of protocols (how are they doing it?)
6. A maelström of action (when can we expect it?)
7. What’s coming over the horizon?

1. The solution seascape

Marine CDR constitutes a plethora of widely varying technologies. Even solutions conveniently grouped in the same bucket may have stark differences in chemistry, equipment and implementation. I won’t go into full depth, but if you’re interested, here is an overview of some recently published resources.

• The National Academies have published their assessment of ocean-based CO2 removal technologies, proposing budgets and timelines to determine the viability and trade-offs of the different technologies. (2021)
• ClimateWorks also notes in their report that screening the different approaches requires the development of a broader scientific basis and that it’s paramount to bring the whole community on board, including (Feb 2021)
• The World Resource Institute (WRI) goes beyond the scientific and the governance angle and is diving into the gigaton potential, the costs, and co-benefits/risks, acknowledging the balance of risks and expected benefits. (Nov 2022)
• The National Oceanic and Atmospheric Administration (NOAA) strategic report on carbon dioxide removals, with a comprehensive evaluations of the key marine CDR technologies. The report also dives into the suite of tools and observations NOAA has at its disposal that could help in the deployment of mCDR. (May 2023)
• Ocean Visions published an illustrative fact sheet of the different technologies, as well as a high-level roadmap to prove or disprove marine CDR. Ocean Visions argues that the discussion on how marine CDR could curb the climate crisis misses field data, and is proposing a rapid, comprehensive R&D effector to answer fundamental questions on the potential of the key mCDR technologies. (Oct 2023)
• Climateworks and the Prince Albert II of Monaco Foundation published the “Best Practices Guide to Ocean Alkalinity Enhancement Research” in a peer-reviewed journal. It comprises chapters on the most pertinent research questions, assembled in a bottom-up research community approach. (Nov 2023)
• A couple of recent layperson explanations in major journals include TIME, The Economist, The Scientific American, and Deutsche Welle.

If you only have 5 minutes, I suggest this explainer video from Ocean Visions, covering the key marine CDR technologies:

Some of the key marine CO2 removal technologies explained in less than 5 minutes.

For the purpose of this article, I will focus on the 3 technologies with the most traction to date:

• Direct Ocean Capture (DOC): extracting and removing CO2 from the ocean in a gaseous form, which is then utilized or stored.
• Ocean Alkalinity Enhancement (OAE): adding alkalinity (base) to the ocean so it can take up more CO2 (weak acid).
• Biomass sinking: as the name suggest, sinking terrestrial or marine biomass to depths where it is stable and locked away.

2. Plenty of fish in the sea

So let’s dive a little deeper, and figure out what some fishes have been up to. Any overview will necessarily be incomplete, and I welcome any references that I may have forgotten.

TL;DR — Partnerships are paramount

• Captura, a Direct Ocean Capture player, has entered in a number of first-of-a-kind partnerships. After receiving a Series A investment from Equinor Ventures (and others), Captura is now also partnering with Equinor to construct and test one of the first plants, removing 1'000 tons of CO2 from the ocean annually, and storing it underground, within the Northern Lights carbon storage infrastructure in the Norwegian North Sea. This makes Equinor both an investor, developer and a client of Captura, making it multidimensional partnership.
  Earlier in the year, Captura also entered a partnership with Deep Sky. This Canadian start-up will be developing and building a first-of-a-kind central lab where it will test and optimize different carbon removal processes, after which Deep Sky will scale and mass-produce the most promising technologies.
• Equatic (previously known as SeaChange , an electrochemical OAE player, also entered into a partnership with Deep Sky, commissioning a 365 ton-per-year pilot plant for further development. On top of that, Equatic is already deploying carbon removal pilots in LA and Singapore.
  On the CDR credit side, they announced in May a pre-purchase deal with Boeing, covering 62'000 tons of CO2 removal and 2'100 tons of green hydrogen (a by-product of their process). Forbes estimates the value of this deal to be worth “at least $50m”. Finally, Equatic made it on Time’s Best Inventions of 2023 list.
• Ebb carbon raised a $20m Series A in April 2023, which got a lot of press, including from Business Insider, Anderson Cooper’s CCN and Fast Company.
  Ebb also entered into a partnership with PNNL for their first 100 ton per year pilot in the Pacific Northwest. The technology will be deployed at scale, where the validity will be tested, as well as its effect on ocean ecosystems.
• Running Tide, an ocean health company using “carbon buoys” to store announced earlier this year that they raised a $54m Series B in Jan 2022, led by Lowercarbon Capital, a VC fund that invested in several other CDR companies including Charm, Arca, Heirloom, Noya, UNDO and others. This announcement was overshadowed by the news that in August, they delivered the inaugural open-ocean CDR credits for Shopify, a first within the broader field.
  On the development front, Running Tide partnered with Ocean Networks Canada, an ocean-observation facility at the West Coast of Canada, to install a deep-sea observatory to measure and verify the carbon removed using Running Tide’s technology.
• In other news, Heimdal, which previous pursued an ocean-based carbon removal process, has pivoted to DAC and SeaO2 was selected for CDR credit pre-purchase by Klarna earlier in 2023. Undoubtedly, there are many other signs of interest in marine CDR.

Finally, I write a lot about technological CO2 removal, but there is tremendous potential in nature-based Blue Carbon solutions as well. I recently wrote a chapter on mangrove restoration in Indonesia as part of a report on public-private-philanthropic partnerships in climate and nature action, some key conclusions here. Some additional sources are a McKinsey & Co report on the potential and the value of Blue carbon, the World Economic Forum’s “Blue Carbon Action Partnership” initiative and the World Bank’s investment framework for Blue Carbon projects more broadly.

3. Diving into the demand

When I applied with Out of the Blue for Stripe’s Spring ’21 CDR purchases (the predecessor of what has become Frontier), marine CDR technologies were scarce. At the time, I wrote about the lack of ocean-based ideas in this a Medium post.

How times have changed!

I already referenced a couple of high-profile purchases in the previous section, but equally telling of the perceived potential of marine CDR are the smaller purchases by the leading CDR Advance Market Commitments.

In the last cycle, Frontier made pre-purchases from no less than 6 ocean-based purchases, including :

• 2 Direct Ocean Capture companies (Carbon Blue, Banyu Carbon)
• 2 Ocean Alkalinity Enhancement companies (Planetary , CarbonRun)
• 2 ocean-based biomass storage companies (Rewind.earth and Carboniferous)

PS: you can find a wealth of information of the technologies behind these start-ups in their open-source Frontier applications. This transparency is something that could potentially greatly help the field as a whole.

Screenshot of Frontier’s Fall 2023 CDR purchases, almost a third of this cycle being composed of ocean-based solutions, including 2 BiCRS solutions that use the ocean for storage.

4. Regulatory tides, rising support

On top of the support from the buyers on the nascent CDR market, there has also been a surge in regulatory support:

• At COP28, the Ocean Pavilion is drawing attention to the recognition of the ocean in the regulation of the climate, and the importance of rebalancing this delicate ecosystem. It brings together 70+ leaders in this space.
• One of the key uncertainties in any marine CDR project, are the rules of engagement, particularly unclear in international waters, governed by the London Convention and Protocol. There are discussions within a revision of the document to include ocean-based Carbon Removals.
• The White House Office of Science and Technology Policy (OSTP) formed a brand new committee on marine CDR, and the US Department of Energy (DOE) released $36M for 11 projects in the space — ARPA-E’s SEA-CO2 project
• The Sabin Center for Climate Change Law at Columbia University published a report recommending actions that US federal agencies could be taking to “ensure safe and responsible permitting and regulation of ocean-CDR research in the US”. This report follows the publishing of a book on the legal framework for mCDR.

Moreover, private and philanthropic organizations are following suit:

• The Carbon to Sea Initiative is an nonprofit that aims to evaluate whether ocean alkalinity enhancement can safely remove and store billions of tons of CO2, bringing together various stakeholders in the community. The $50M initiative was spun out of Additional Ventures. (launched June 2023)
• [C]worthy is building the tools that are needed to evaluate and quantify ocean-based CDR, including multi-scale biogeochemical oceanographic modeling. Currently incubated, they want to become a focused research organization supporting players across the field. (launched 2023)
• Submarine.earth is an ocean data company “using satellite data, AI, and earth system modeling to support, measure, and verify ocean-based carbon removal”. (founded 2022)
• atdepth MRV is building the modeling, monitoring and data assimilation tools needed to create digital twins of human interventions in the ocean to enable ocean-CDR (founded 2023)
• The Chan Zuckerberg initiative is earmarking some of the $44M grants for ocean-based CDR solutions. A unique mix of financing strategies will be employed, including grants, investments and pre-purchases from the companies.
• Venture Capital fund Propeller is partnering with some of the world’s leading ocean science institutes to accelerate ocean-climate companies with their $100M fund, and find “tomorrow’s narwhals” (launched Oct 2022)
• Other supporting initiatives include PlanBlue, Ocean Ledger and Aquatic labs and the Washington Sea Grant. There are also companies focusing on building the equipment for the measurements, such as Nortek or Open Ocean Robotics.

“Finding tomorrow’s Narwhals” — Propeller. From Wikimedia Commons.

5. A deluge of protocols

In the absence of a standardized framework for marine carbon removal technologies, a lot of the marine CDR players have been publishing their own frameworks and methodologies for quantification of the removals and assessment of co-benefits and risks.

• Planetary’s MRV (Measurement Reporting and Verification) Framework describes the processes and measurements to assess the lifetime carbon removal and cost, and also covers the tools for assessing the environmental impact. (v2.0 in Feb 2023, updated on regular basis)
• Running Tide’s framework for open-ocean carbon removals proposes a protocol for accounting of carbon removals in a “fast-to-slow” transition, referring to the two carbon cycles governing the ocean: a fast one in the top layer, and a slow one on the ocean floor. (Apr 2023)
• Equatic has published their methodology as a peer-reviewed scientific paper, focusing on the mass and energy balances of the system, and on the quantification of the geochemical changes in the ocean. (Apr 2023)
• Captura also gives a detailed description of their process in their open-sourced MRV protocol, and then breaks down the CO2 removed and emitted during it. (Oct 2023, updated on regular basis)
• Brilliant Planet worked with advisory firm EcoEngineers to write a methodology for CO2 removal from ocean microalgal blooms (Nov 2023)
• Several mCDR players are assignees to the Reykjavik Protocol, which describes a set of best practices for nature-deployed carbon removals, to reduce the uncertainties and improve the transparency (Oct 2023)

6. A malström of action

What’s really remarkable, is the pace at which this space is evolving.

Marine CDR technologies are the new kid on the block compared to other carbon removals: DAC (Direct Air Capture) and BECCS (Bio-energy with Carbon Capture and Storage) ware already proposed around the turn of the millennium as climate solutions, and have been pursued commercially for over 15 years.

In contrast, the pursuit of marine-CDR is a much more recent endeavor, but is nevertheless evolving at neck breaking speed:

• Running Tide was founded in 2017, and has delivered the first at-scale commercial credits earlier this year.
• Captura was founded in 2021, and plans to commission the 1'000 tpa DOC plant in Norway already next year (2024).

It should be noted that while these start-ups are young, they are often building off earlier momentum, both off that of their CDR-predecessors (that helped de-risk the investment and business case) as well as adjacent technology development (e.g., ocean liming is frequently used as an aquaculture practice, and there is prior patent literature and research to build on for electrochemical processes for CO2 extraction).

7. What’s coming over the horizon?

From my enthusiastic listing of all the recent news, you might be forgiven for thinking the problem is solved. However, as with any new technology, there is a lot of technological and commercial risk and uncertainty that needs to be resolved before it can scale to a climate-relevant size.

The devil is in the detail

Unfortunately, there is no single unlock across the different marine CO2 removal technologies. Some might have uncertainties in their supplies chains (both up and downstream in case of by-products), others might have trouble from a project management point-of-view, still others might find it harder than expected to come down cost curves fast enough. There is a lot of nuance in the different technologies (don’t get me started on electrolysis vs electrodialysis, acidic vs basic route, direct or indirect CO2 removal), and deep expertise is required to weigh the potential of every process.

The seascape has changed beyond recognition in just a few years, and it’s safe to say that a lot of disruption can be expected in the years to come. But one thing is for sure: the ocean plays a key role in the global carbon cycle, and the full potential is only just being tapped. Entrepreneurs, investors, policy makers: take note!

Dr. Lennart Joos has CO2 running through his blood and has been working on the topic for over a decade. He is Carbon Tech Expert at McKinsey & Co, helping companies scale fast on the carbon capture/removal market. Before that, he pursued ocean-based CO2 removal start-up Out of the Blue. Always open for collaboration, you can reach him on lennart@co2outoftheblue.com or via LinkedIn.