While the world debates carbon taxes and electric vehicles, a quiet revolution is brewing beneath the waves. Scientists have just delivered the world’s first ocean-based carbon removal credits, and the numbers are staggering:
Equatic: Scaling Industrial Ocean Carbon Removal
What began three years ago as a U.S. Department of Energy-funded research project at UCLA has rapidly evolved into one of the most ambitious marine carbon removal ventures in the world. Equatic, the company born from this research, is preparing to build a massive marine carbon capture facility in Quebec that will rival the world’s largest terrestrial carbon removal facilities.
Equatic’s technology centers on electrochemical ocean alkalinity enhancement. The process begins by pumping seawater into tanks and using electrical current to electrolyze the water, splitting molecules into oxygen and hydrogen gases while extracting an alkaline slurry. This solution is then reacted with air, pulling carbon dioxide from the atmosphere and chemically transforming it into two valuable byproducts: calcium carbonate (used in agricultural lime) and a bicarbonate solution that is safely returned to the ocean.
The scale of Equatic’s ambitions is staggering. While their Singaporean pilot facility houses 10 electrolyzers and processes 4,000 tonnes of carbon annually, the planned Quebec facility will contain 300 electrolyzers capable of removing 110,000 tonnes of CO2 per year—equivalent to the emissions from 24,000 cars.
Edward Sanders, Equatic’s chief operating officer, emphasizes the technology’s advantages: “Compared with efforts to capture carbon directly from the air, the net energy intensity of the process is low. We do all the measurement and carbonation on land, so we can accurately record the extent of the carbon dioxide removal.”
Planetary Technologies: Delivering the World’s First Ocean Alkalinity Credits
In November 2024, Planetary Technologies achieved a historic milestone by delivering the world’s first net ocean alkalinity enhancement carbon removals. The 138 tonnes of CO2 removed through their Halifax project represents a technical achievement; it’s proof that ocean-based carbon removal can be both safe and commercially viable.
Planetary’s approach to ocean alkalinity enhancement emphasizes collaboration and scientific rigor. Working with partners including Dalhousie University and Nova Scotia Power, the company has developed breakthrough measurement techniques and demonstrated environmental safety at operational scale. Early results from their Halifax project show no measurable impacts on the local ecosystem and no accumulation of metals or toxins in sediments.
The significance of Planetary’s achievement extends beyond the immediate carbon removal. Shopify received 96 tonnes and Stripe 42 tonnes of these first credits through Frontier’s advance market commitment, demonstrating the growing corporate demand for high-quality marine carbon removal. CEO Mike Kelland reflects on the milestone: “Delivering the first net OAE credits is a monumental step, not only for Planetary but for the entire field of ocean-based carbon removal.”
Planetary’s strategy focuses on “scaling out” rather than simply “scaling up”—a holistic approach that prioritizes collaboration with local communities, scientific rigor, and environmental stewardship. This philosophy could become a model for responsible development of marine carbon removal technologies.
Captura: Integrating with Existing Infrastructure
California-based Captura is pursuing a different approach to marine carbon removal, focusing on integration with existing coastal infrastructure to achieve rapid scale and cost reduction. The company’s electrodialysis-based system draws CO2 directly from seawater, then returns the carbon-depleted water to the ocean where it causes additional atmospheric CO2 to dissolve.
Captura’s strategic advantage lies in its ability to partner with desalination facilities, which produce large volumes of salty brine that can be fed directly into the company’s electrodialysis system. This integration allows Captura to skip filtration and other processing steps, making the process faster and more cost-effective.
Following successful pilot projects in Los Angeles, Captura is preparing for a final test in Hawaii using a process expected to capture 1,000 tonnes of carbon dioxide annually. Tara Bojdak, the company’s communications director, explains their scaling strategy: “Our technology and business model are all about how we can get to that large scale and low cost and do it as quickly as possible, so we can start to have a bit of an impact on climate change.”
Ebb Carbon: Microsoft’s Marine Carbon Partner
Ebb Carbon has emerged as a significant player in marine carbon removal through its partnership with tech giant Microsoft. The company’s electrodialysis-based pilot plant in Port Angeles, Washington, will remove 500 tonnes of CO2 annually for two years as part of a larger agreement to provide Microsoft with 350,000 tonnes of carbon removal.
The Microsoft partnership represents more than just a commercial transaction, it’s part of a broader effort to establish quality standards for marine carbon removal. Microsoft and Carbon Direct have collaborated to develop criteria for high-quality marine CDR, focusing on environmental safety and accurate measurement. This work is helping to create the frameworks needed for responsible scaling of ocean-based carbon removal.
Vesta: Harnessing Natural Minerals
Vesta takes a different approach to ocean alkalinity enhancement, using olivine sand to enhance the ocean’s natural ability to remove carbon dioxide from the atmosphere. The company has completed deployment of the first U.S. standalone ocean alkalinity enhancement project, demonstrating the potential for mineral-based approaches to marine carbon removal.
Olivine is a naturally occurring mineral that weathers when exposed to seawater, releasing alkalinity and enabling additional CO2 absorption. Vesta’s approach involves carefully distributing olivine sand in coastal environments where natural wave action accelerates the weathering process. This method offers the potential for lower energy requirements compared to electrochemical approaches, though it requires careful environmental monitoring to ensure safety.
The Seaweed Revolution: Biological Carbon Removal at Scale
While electrochemical approaches dominate current commercial development, biological marine carbon removal is gaining momentum as companies develop technologies to harness the ocean’s natural carbon-absorbing organisms. Seaweed farming, in particular, has emerged as a promising approach that combines carbon sequestration with ecosystem restoration, sustainable product development, and economic opportunity creation.
Seafields is pursuing perhaps the most ambitious biological carbon removal strategy, developing open-ocean seaweed farming systems designed to remove billions of tonnes of CO2. The company’s approach involves creating floating farms in international waters, where vast areas can be dedicated to seaweed cultivation without competing with other ocean uses.
The technical challenges of open-ocean seaweed farming are immense, requiring systems that can withstand storms, maintain structural integrity across vast distances, and operate autonomously for extended periods. However, the potential rewards are equally significant. Open-ocean systems could theoretically scale to sizes that would make meaningful contributions to global carbon removal targets.
Seafields has successfully raised funds to develop their technology, demonstrating investor confidence in the potential for open-ocean biological carbon removal. The company’s “smart solution” approach emphasizes the development of automated systems that can operate efficiently at massive scale.
Other companies are pursuing biological carbon removal through product-focused strategies that create economic value from seaweed while contributing to carbon sequestration. Blue Evolution positions itself as “a pioneering company for the climate era,” converting seaweed into essential products that traditionally rely on unsustainable feedstocks.
Next Wave Seaweed takes a different approach, focusing on co-located seaweed farming that is “responsibly sited and managed.” The company emphasizes that nature-based carbon removal solutions like seaweed are often lower-cost and more accessible than technological approaches, making them attractive for widespread deployment.
Ocean Rainforest represents another ambitious approach to seaweed-based carbon removal, operating an 86-acre seaweed farming project with the goal of producing 1 million tons of seaweed annually by 2030. The company’s focus on fighting climate change through large-scale seaweed cultivation demonstrates the potential for biological approaches to achieve meaningful scale.
The company’s approach emphasizes the development of industrial-scale seaweed production systems that can operate in open ocean environments. This focus on scalability is crucial for biological carbon removal to make a significant impact on global carbon levels. Ocean Rainforest’s timeline—reaching 1 million tons annually by 2030—provides a concrete benchmark for the industry’s scaling potential.
The Science Behind Seaweed Carbon Removal
Recent scientific research has provided strong validation for seaweed-based carbon removal approaches. Studies by the International Atomic Energy Agency have shown that seaweed farms store carbon as effectively as natural coastal ecosystems, significantly increasing the potential of marine carbon removal methods.
Research published in 2025 confirms that if expanded worldwide, seaweed farming could remove up to 140 million tons of CO2 from the atmosphere every year by 2050. This research provides compelling evidence that biological approaches could make substantial contributions to global carbon removal targets.
The research also demonstrates that seaweed can bio-sequester atmospheric CO2 into biomass, making it a viable carbon dioxide removal strategy. However, scientists emphasize the importance of considering the full lifecycle of seaweed products to ensure that carbon removal claims are accurate and permanent.
Kelp Blue: Gigaton-Scale Ambitions
Perhaps no company better embodies the ambitious vision of biological marine carbon removal than Kelp Blue, which aims to cultivate giant kelp on large-scale offshore structures to “re-wild our oceans, lock away carbon, and create a range of high-performing biostimulants.” The company’s 2050 vision is breathtaking in scope: kelp farms that sequester 0.2-0.5 gigatons of CO2 per year; more than the Netherlands’ entire annual emissions.
Kelp Blue’s approach centers on Macrocystis pyrifera, or giant kelp, one of the fastest-growing organisms on Earth. These remarkable algae can grow up to two feet per day in optimal conditions, rapidly converting dissolved CO2 into biomass. The company cultivates this kelp on offshore structures, then processes it into StimBlue+, a premium biostimulant that helps farmers reduce their reliance on chemical fertilizers.
The environmental benefits of Kelp Blue’s approach extend far beyond carbon removal. Their kelp farms increase localized marine biodiversity and ecosystem resilience, reduce ocean acidity, and provide major boosts to regional fish stocks. The company operates with zero waste, chemicals, fertilizers, or pesticides, creating what they describe as a “net benefit to the environment.”
The economic model is equally compelling. It creates a high-value biostimulant products from cultivated kelp, Kelp Blue generates revenue streams that can support the scaling of their carbon removal operations. The company has demonstrated the effectiveness of their products across diverse crops including barley, corn, wine grapes, tomatoes, olives, almonds, and strawberries, working with farmer ambassadors across Europe and beyond.
The blue carbon revolution is attracting unprecedented investment and policy attention as governments and corporations recognize the potential for ocean-based climate solutions. According to recent analysis, ocean-based climate solutions can get us as much as 35% closer to emissions reduction targets for 2050, making marine carbon removal a critical component of global climate strategy.
Government Support and National Strategies
Government support for marine carbon removal is growing rapidly, with the United States leading the development of national strategies for ocean-based carbon removal. In November 2024, NOAA, the White House, and other federal partners released a national strategy for marine carbon dioxide removal research that outlines how the U.S. government can accelerate mCDR research in a safe and effective manner.
The U.S. strategy emphasizes the importance of environmental safety, scientific rigor, and international cooperation in developing marine carbon removal technologies. This government support provides crucial validation for the industry and helps establish the regulatory frameworks needed for responsible scaling.
Measurement and Verification Complexities
Accurate measurement and verification of carbon removal remains one of the most significant technical challenges facing marine carbon removal. Unlike terrestrial carbon storage, where carbon can be measured in soil and biomass, oceanic carbon exists in dissolved forms that require sophisticated monitoring techniques.
Companies are developing innovative solutions to this challenge, but the complexity of ocean systems makes verification inherently difficult. Ocean currents can transport carbon-enriched water across vast distances, making it challenging to determine how much carbon removal can be attributed to specific interventions.
The development of robust measurement and verification protocols is essential for building trust in marine carbon removal and enabling the creation of high-quality carbon credits. Microsoft and Carbon Direct’s collaboration to develop criteria for high-quality marine CDR represents an important step toward industry standardization.
