A philanthropic consortium, led by Additional Ventures, is proud to launch the Ocean Alkalinity Enhancement (OAE) R&D Program, an ambitious effort to accelerate understanding of OAE as a potential method for large-scale carbon dioxide removal (CDR).

The Promise of Ocean Alkalinity Enhancement

Ocean alkalinity enhancement is a particularly promising ocean CDR approach. Below is a visual representation of key quantitative and qualitative results summarized by NASEM (2021, Table S.1 therein). Note that some of the most cost-effective and scalable “electrochemical processes” described in NASEM (2021) increase the alkalinity of seawater, and/or force the precipitation of solid alkaline materials that can be used for OAE. Our definition of OAE encompasses these electrochemical approaches.

While OAE is potentially efficient, permanent, and scalable on paper, it remains a theoretical concept with many open questions which we hope to answer.

Under what conditions does OAE most efficiently sequester atmospheric CO₂?

Developing the most efficient deployment strategy requires identifying and understanding the main factors that will impact CDR efficacy. These factors include location (e.g., physical and biogeochemical environment where the alkalinity is added) and the mode, frequency, and rate of alkalinity addition. CDR inefficiencies and challenges around carbon accounting stem from processes that occur once the alkalinity source is added to the seawater. This includes particle dissolution rate (when adding minerals), secondary precipitation, and CO₂ gas exchange dynamics.

Can OAE be cost-effectively deployed at scale?

Irrespective of the mode of alkalinity enhancement, estimated costs remain above (or close to) $100 per net ton removed, largely as a result of high energy costs. Over the past 10-15 years, researchers have explored different solutions to reduce costs and speed up dissolution rates.

How can desired and undesired effects be identified, measured, monitored, and mitigated?

Large-scale and permanent modification of seawater carbon chemistry will have desired and undesired environmental impacts, and these impacts are likely to differ across the various modes of alkalinity addition. In the absence of data from mesocosm and field trials, it is difficult to predict these changes and to develop meaningful frameworks for monitoring, reporting and verification (MRV). Any MRV framework will have to focus on two major questions however. First, how much CO₂ is permanently moved from the atmosphere to the ocean and how quickly does this happen (carbon accounting)? Second, what are the undesired effects of OAE on marine organisms and ecosystems (monitoring of environmental impacts) and how can they be mitigated?

The Ocean Alkalinity Enhancement R&D Program is an ambitious effort to evaluate the technical feasibility of alkalinity enhancement as an efficient method for sequestering atmospheric CO₂, and to identify under what conditions it could be deployed safely. Additional Ventures is committed to funding R&D in a responsible manner that accords with all applicable laws and regulations. We recognize that modification of seawater carbonate chemistry may have undesired environmental impacts, and that further research may show that these outweigh the benefits of alkalinity enhancement in permanently removing CO₂ from the atmosphere. We believe that OAE R&D needs to be conducted with a prudent, step-by-step approach and that the nature, scale, duration, and intensity of experimentation and technology development should be proportionate to the current state of knowledge about potential adverse effects.