A startup in Nova Scotia is conducting trials on a technique to capture and retain more carbon in the ocean by utilizing a new experimental facility to validate the idea. The ocean already serves as a significant repository for excessive carbon dioxide, having absorbed roughly 30% of all carbon emissions caused by human activities since the 1980s. pHathom, the company behind this initiative, aims to further reduce emissions from the atmosphere by capturing carbon dioxide and transforming it into a form that can be securely stored in the ocean for thousands of years.
The company’s method involves replicating a natural process where raindrops absorb carbon dioxide as they fall from the sky, subsequently becoming slightly acidic. When these raindrops interact with alkaline rock like limestone, a portion of the rock dissolves, reducing the acidity of the water and converting the carbon dioxide into bicarbonate. Ultimately, this bicarbonate reaches the ocean, where it can be stored for extensive periods, effectively preventing carbon dioxide from re-entering the atmosphere. pHathom mimics this process within a reactor by exposing seawater to the emissions of a biomass power plant, leading to a chemical transformation that results in the conversion of carbon dioxide into bicarbonate before reintroducing the treated water back into the ocean with the same pH level as regular seawater.
Other companies in Nova Scotia are also exploring variations of this carbon removal approach, known as alkalinity enhancement. For instance, Planetary is implementing a project in Halifax to raise the pH of seawater by adding alkaline rock, while CarbonRun is deploying a similar strategy on rivers in the region. pHathom’s method holds an advantage due to its utilization of highly concentrated carbon dioxide, increasing operational efficiency. The pilot phase aims to capture 0.1 tonnes of carbon dioxide daily, with the process generating treated water for testing tanks to assess its impact on various marine species over a three-month period.
If successful, pHathom plans to expand its operations with a second test site in Nova Scotia next year, integrating their reactor into a building transitioning from a fossil-fuel boiler to a biomass system. Despite the potential of carbon removal technologies, scalability remains a critical challenge, as indicated by modeling from the Intergovernmental Panel on Climate Change (IPCC) suggesting the necessity of scaling global carbon dioxide removal to significant levels to limit global warming. Researchers and experts emphasize the need for rigorous evaluation and regulatory frameworks for these technologies to be considered viable solutions for climate mitigation.
