Cornwall FAQs

Planetary is on a mission to fight climate change by helping the ocean remove carbon dioxide from the atmosphere. It packages together everything needed to develop and operate a responsible OAE project.

Ocean Alkalinity Enhancement (OAE) is a process inspired by nature that enables the ocean to safely capture excess atmospheric carbon and store it for 100,000 years. By adding an antacid to seawater, we neutralise carbon dioxide (CO2) and reduce harmful ocean acidity. The result is the safe, permanent removal of CO2 from the atmosphere, which helps to combat ocean acidification and climate change through the restoration of seawater.

Our vision is to enhance the one of the planet’s largest natural carbon removal and storage process at many suitable locations around the world.

Scientific progress relies on rigorous testing, and small-scale trials allow us to evaluate the impact, effectiveness, and safety of ocean alkalinity enhancement (OAE) in real-world conditions. These trials provide invaluable data that help refine our approach before any potential wider deployment. 

Planetary begins each of its OAE projects cautiously and scales up only as we are reassured that the project can be operated safely and effectively. Our scaling process is informed by collaboration with local non-profits, regulators, and community members.

Every location is carefully selected, and trials are conducted transparently, with oversight from independent experts. Our Cornwall project was based in St Ives Bay, near the town of Hayle. The site was selected due to its ideal ocean conditions for scientific study, including water chemistry and coastal dynamics. It was also identified as a suitable location through the assessment and support process of a UK Government grant.

The trial in Cornwall marked a world-first demonstration of ocean alkalinity enhancement (OAE) using mineral additions to wastewater effluent, providing valuable scientific insights into carbon dioxide removal (CDR). The results, now published in a peer-reviewed journal, confirmed that the approach can sequester carbon effectively, with only minimal and temporary localised impacts.

In addition, the Environment Agency published an independent assessment, produced by the Water Research Centre (WRc), which found that Planetary’s process has the potential for significant net carbon removal. 

These findings support the broader scientific consensus, including the IPCC’s Special Report on the Ocean and Cryosphere, which highlights the critical role oceans must play in addressing climate change. The insights from Cornwall are now informing our wider programme of trials, which you can read more about here.

Planetary has now ceased all trial operations in Cornwall; we are not currently conducting any trials elsewhere in the UK.

 

The trial in Cornwall was deemed a success, yielding valuable scientific data and insights. While we recognize the potential of this approach, we will not pursue a full programme in Cornwall for commercial reasons – specifically the inability to locate and deliver a cost-effective alkalinity source. 

This research is crucial in advancing our understanding of ocean-based carbon removal and its role in tackling climate change. We deeply appreciate the support and engagement of the community in enabling this work. Our vision is to enhance the planet’s largest natural carbon removal process at many suitable locations around the world, and we hope the UK will continue to play an important role in the future.

Yes, the results from the Cornwall trial have been published in a peer-reviewed journal and can be accessed [here].

As the very first field trial of its kind, the results reported in this paper are critical to support our understanding of ocean alkalinity enhancement (OAE).

The key takeaways were: 

• Adding alkalinity (in this case, magnesium hydroxide) to wastewater converts the CO2 in the wastewater into dissolved carbonates and bicarbonates, thus reducing the amount of CO2 emissions that would otherwise be emitted to the atmosphere.
• The impact on ocean chemistry was minimal and undetectable beyond five meters from the point of addition, 
• The alkalized water rapidly diluted, confirming the need for ocean modelling to estimate CO2 removal at scale.
• The findings validate that OAE, when properly controlled, is effective at carbon sequestration. 

This research provides a strong foundation for further exploration at scale. The Hayle 2022 methods test was a world-first demonstration of OAE by mineral addition to wastewater effluent and its potential as a carbon dioxide removal solution and laid the foundations for our 2023 pilot project in Halifax, Nova Scotia.

Planetary conducted a small-scale field trial at the wastewater treatment plant in St Ives Bay in September 2022. Given the small scale of the trial, and following guidance from the regulator and South West Water, it was not broadly publicised ahead of time.

After the trial, we began broader engagement in October 2022 with local stakeholders — including MPs, Cornwall Council, universities, public advocacy groups, and conservation organisations — to explore the possibility of a larger-scale demonstration. While that subsequent trial ultimately did not proceed, we are now formally concluding this phase of our work in Cornwall.

The 2022 trial has since undergone rigorous independent review, and the results have been published in a peer-reviewed journal [here].

Following the trial, we also undertook further research into alkalinity sources and supply chains. Based on this analysis, the scale-up of operations in Cornwall has been assessed as commercially unviable, and we will not be pursuing a wider programme in the region.

We do not expect any long-term impact on the local ecosystem following our trial. The findings confirm that the addition of alkalinity had a minimal and highly localised effect on seawater, which ceased once the trial concluded.

St Ives Bay is vital to the Cornish community and economy, and we were pleased that the trial demonstrated such a minimal environmental footprint. The learnings from Cornwall have laid a strong foundation for our ongoing pilot project in Halifax, Nova Scotia.

The announcement marks one year since the WRC published its independent report into the results of our trial in Cornwall. Since then, we have spent time finding a local, cost-effective alkalinity source. 

 

The announcement has come today as we have been unable to find a viable new alkalinity source. The conclusion of our trial therefore marked the end of our work in Cornwall. We are not currently conducting any trials elsewhere in the UK. 

No, we are not currently conducting any trials elsewhere in the UK. 

However, our vision is to enhance the planet’s largest natural carbon removal process at many suitable locations around the world, and the UK will continue to play a role in this work in the future. 

More information about current projects can be found here. 

Before selecting Cornwall, we assessed a number of potential sites across both the UK and Canada. Each trial site is chosen through a careful process that considers many factors including alkalinity source, scientific feasibility, potential climate impact, and meaningful engagement with local communities.

Although our work in Cornwall has now concluded, we’re deeply grateful for the opportunity to collaborate with local stakeholders on this pioneering research. The data, insights, and lessons gained from the trial will continue to inform and strengthen our mission to advance safe, effective ocean-based carbon removal worldwide.