Cornwall FAQs

The team at Planetary is grateful for the engaged participation of the Cornwall community regarding our work. The following Frequently Asked Questions (FAQs) reflect the themes of the most often raised questions or comments during our initial community outreach session – including some more detailed questions assembled by a self-organised group of concerned citizens in the region. Our goal for each question is to briefly address the overall theme of each question with our intended approach. We recognise that there are many perspectives at play in the community and aim to target our responses at the “curious and concerned citizen” with our FAQs. Recognising some groups of people  (e.g. activist, scientist, etc.) may be interested in a more detailed answer, or wish to explore a different facet of the topic, we invite you to continue to reach out to us with your additional questions.

How does Planetary plan to monitor biological impacts before, during, and beyond the study period?

We believe that all our studies are safe. We won’t conduct studies that we think are likely to cause harm. That simply would go against everything we believe in – our code of conduct, the scientific method, and our dedication to restore the ocean. This is why we have developed a rigorous monitoring program that will make sure our assumptions are correct and nothing unexpected occurs.

We have written and published this blog to outline our monitoring process before, during and beyond this study that will last up to 120 days.

Lead Responder: Dr. Will Burt
Chief Ocean Scientist

Why are we (the Cornwall community) only hearing about this now?

Lead Responder: Pete Chargin, VP, Commercialisation and Community Relations

We have been in the process of identifying promising sites for carbon removals for over two years. We began the process of community outreach in October of 2022 – more than five months ago. We started by engaging with government officials and public groups. This included Members of Parliament, members of Cornwall Council and their scientific staff, researchers at local universities like Exeter University and the National Oceanography Centre, members of public advocacy organisations such as Carbon Gap and Surfers Against Sewage, and members of local conservation groups such as the Cornwall Wildlife Trust. 

Once we had obtained initial approval and encouragement from the local regulator to proceed, we began in January to reach out to fishers, more conservation groups, surfing groups and other marine groups through the Marine Liaison Group. We planned and convened our first open public meetings – starting in Hayle –  and publicised those meetings through radio, newspaper, a press release, and email communication to all the previously engaged organisations. 

Based on the questions and feedback we’ve received so far, we’ve made adjustments to our project plans.  These adjustments include increased monitoring during the trial and working with local Universities to develop a longer term post-trial monitoring plan.

It was never our intent to surprise anyone or to leave people out. In that spirit, if you would like to hear about all future public meetings and to keep in touch as we make progress in this proposed project, please sign up for our dedicated Hayle and St Ives newsletter, available at the bottom of the Cornwall Project Page.

We’re happy to receive feedback and answer questions through our direct email address as well at 

What safeguards are there at the mining / mineral processing stage to ensure no toxic minerals enter the ocean?

Lead Responder: Jason Vallis
Vice-President, Operations

We have a multi-step process and several safeguards in place to ensure the mineral added to treated wastewater effluent is fully compliant with UK Environmental Quality Standards (EQS).

First, we work with mineral suppliers to select products that are already in use for wastewater treatment. We have chosen magnesium hydroxide for many reasons; one of the main ones is that it has been safely used in water treatment for decades. We then have samples sent to an independent third-party mineral testing facility to conduct trace element analysis. This allows us to measure any impurities in the product and assess its variability. 

Next, we compare the elemental analysis results with UK EQS for coastal waters. This allows us to predict how much magnesium hydroxide can be added as a percentage of the effluent flow rate, as well as how much can be added over a given period of time, while complying with these standards. 

We will conduct elemental analysis on each batch of magnesium hydroxide prior to shipping. Any batch that does not meet UK EQS standards at the base addition rate will not be accepted. 

Throughout the addition phase, we will be taking treated effluent samples upstream and downstream of the addition point to measure any baseline impurities in the effluent, as well as any changes as a result of addition. 

As a final safeguard, we are working with Plymouth Marine Laboratories to collect water column and sediment samples at and around the outfall to determine if a difference in trace element concentrations can be detected over baseline samples.

We are a fishing community. What positive/negative effects could this have?

To orient positive / negative effects to fishers, we need to begin by taking a step back to consider the current impacts of carbon dioxide pollution in the ocean – this particular kind of pollution is called “ocean acidification”:

“Ocean acidification  is literally causing a sea change that is threatening the fundamental chemical balance of ocean and coastal waters from pole to pole. For good reason, ocean acidification is sometimes called “osteoporosis of the sea.” Ocean acidification can create conditions that eat away at the minerals used by oysters, clams, lobsters, shrimp, coral reefs, and other marine life to build their shells and skeletons.” – NOAA Fisheries

Acidification is a grave threat to the fishing community in the UK – in particular shellfish. A recent UK Parliament Publication stated: “UK fisheries are vulnerable to acidification because of the high proportion of shellfish caught and because most of the fin and shellfish catch occurs within UK waters. These are expected to experience increasing acidification, especially around the coast. Aquaculture and inshore fisheries concentrated in coastal waters may be worst hit.”

A report by the Government Office for Science states that “…recent research has indicated that annual economic losses in the UK resulting from the effects of OA could reach US $97.1 million (GBP £74.7 million) by 2100”. 

Our process is based on Ocean Alkalinity Enhancement (OAE) and has the potential to provide a direct, immediate benefit to local fishing – especially shellfish fisheries. Looking at the work done in aquaculture, we can see a good example for the business potential of alkalinity addition. In shellfish aquaculture, alkalinity similar to that used by Planetary is added to hatcheries in order to ensure yields. While the addition in a hatchery is many times more potent than Planetary’s process, since the amount of water is small compared to the alkalinity addition, the overall effect is similar. Looking further into the future, our process also helps longer-term with broader impacts of climate change – where extreme storms and weather events reduce days at sea and encourage marine species to experience migration due to warmer waters and lower oxygen levels.

In addition to our efforts to reduce harmful acidification, we must work hard to ensure our proposed activities do not negatively impact fishing activity in this community, or any community we work. We feel our monitoring plan in St Ives, outlined in the above question, achieves this, and we welcome further feedback from local experts as to how we might further bolster our efforts.

Lead Responder: Mike Kelland
Chief Executive Officer, Co-Founder & Board Member

If the study in Cornwall is deemed a success, you mentioned scaling your project up […] please can you clarify your maths and how you get to your calculations of 1GT of annual CO2 removal by 2035?

Lead Responder: Mike Kelland
Chief Executive Officer, Co-Founder & Board Member

As our company has evolved, we’ve learned a lot. At the outset we set ourselves the goal of 1 Gt (one billion tonnes) by 2035. This was based on looking at high level markers, including the availability of alkalinity sources, the capacity of the ocean to take up additional CO2, and the urgency of the climate crisis. There are a number of reasons that we now see that timeline as unrealistic. One very important factor is the time required to do the science to ensure that a scale up of the process is safe. And then there’s the economic and coincident moral implication – decarbonisation needs to be the priority in the near term and the markets will reflect that – we doubt now that there will be a market that would support a billion tonnes of removal in place by 2035. We’ve therefore set ourselves a new goal of 1 Gt by 2045. This is in alignment with IPCC climate models and the scale up of carbon removal those models tell us that we’ll need.

But why a 1 Gt goal at all? 

Simply put – we believe that setting a high goal helps to shape our thinking. Because we think at climate-relevant scales, we design systems that can sustainably operate at that level. It helps us to make harder decisions today in order to build a better solution for the future. In short – we aren’t spending time on a process that won’t be able to work on a global level.

Having a high goal as a guiding principle means that we: 

  • Invest heavily today in environmental safety and community engagement. It sets us on a path to be here for the long term, and not to just create a short-term and small-scale approach. It forces us to be transparent and incorporate social and environmental justice in our business models rather than punting those questions to the future. 
  • Design systems with strong controls on side effects. For example, it’s pushed us to reject simpler solutions that produce toxic waste streams – the burden of those wastes would be impossible at scale. 
  • Contribute to the general growth of the field, understanding that we work in an ecosystem, rather than trying to capture short term value – as evidenced by the public release of our MRV protocol last month, and as evidenced by our cooperation with research efforts at university and research institutions around the world who are leading the efforts to validate the safety and effectiveness of this process.  

Will we reach 1 Gt/y by 2045? We hope so. But if we don’t, we still believe that building towards that goal is the right thing to do. 

The Hayle discharge rate is many times smaller than other wastewater facilities (about 30 times smaller than Boston MA for example), and several hundred times smaller than other potential discharges such as cooling water loops from power plants. We see this single ocean outfall as a small part of a large network of additional sites, where the total amount of carbon removal can be at the gigatonne level. 

All of these logistical items, however, must be held to the standard of safety. The true limit to scale will be the pace at which science tells us that this process is safe. This is one of the key reasons for this small study – to continue the solid science that has been done in the lab and the ocean around the world. 

How much MH do you need for the experiment this year? Please clarify where the magnesium hydroxide will be sourced and [what are you tracking as CO2 emissions for the project]?

Lead Responder: Jason Vallis
Vice-President, Operations

The total amount of MH required will be dictated by our monitoring plan and independent analysis of effluent samples as well as outfall observations. 

  • The initial MH volume being brought to site will be 100 tonnes (dry weight) or 5 truck loads with the capacity to add up to 450 tonnes (~23 truck loads) over 90-120 days.
  • The MH will be sourced through a reputable US supplier experienced in wastewater treatment pH adjustment with the additional support of UK based suppliers.
  • The emissions inventory for our MH product includes a “cradle to gate” analysis starting from the MH mining site through to the dosing and monitoring points (scope 3), with the final step of the MH being added to the ocean to reduce atmospheric carbon.
  • Embedded estimates, distances, and the emissions factors applied are audited by a third party and always represent a CO2 equivalent figure.
  • Planetary follows the accounting methodologies recommended by the Greenhouse Gas (GHG) Protocol / ISO 14064-2.

The project emissions boundary/ scopes include:

Scope 1

  • Any onsite emissions generated from Planetary owned equipment (the majority of our equipment is electrically powered)

Scope 2

  • Purchased/borrowed energy from the wastewater facility that comes from the UK grid/ power supplier (grid emissions factor averaged)

Scope 3

  • Alkaline (MH) feedstock embedded emissions “cradle to gate
  • Embedded emissions in our pumps, hoses, tanks, electrical equipment, etc. (amortised over the supplier recommended lifespan)
  • Flight, car, bus, and train travel required for the project operations (including contractors and suppliers required on site)
  • Any waste generated in our operations
  • Any additional capital goods (amortised over the supplier recommended lifespan)
  • Any additional emissions generating services or goods used while on site

What amount of CO2 captured [via this study] amounts to a ‘success’ in your view?

Success for this trial is not measured solely in ‘tonnes of CO2 captured’. Generally we have a holistic approach to measuring success (keeping in line with our Code of Conduct), including positive climate improvement, science, transparency, and learning. In this project, we will primarily measure success along these dimensions:

  1. Safe operation with significant amounts of learning; 
  2. Demonstrating that we encounter no unanticipated biological impacts via a robust and transparent monitoring plan; 
  3. Working relationships built with all the constituents involved: regulators; local scientific organisations; local, regional, and national governments; local environmental organisations, local businesses and business people; partners; and local individuals; and
  4. Removal of a small amount of CO2 (on the order of a few hundred tonnes) from the atmosphere. This objective ensures that we begin all the processes required to demonstrably have an impact on atmospheric CO2: identify and transport alkalinity with a low enough carbon footprint, create a robust MRV and measurement plan, work with an appropriate and approved verifier, register the credits appropriately to ensure no double counting, and report publicly the results of the removal efforts. 
Lead Responder: Pete Chargin, VP, Commercialisation and Community Relations

What are the results of the PML Applications monitoring of the September trial? 

PML Applications has provided the following summary regarding their monitoring of the September trial. PML Applications plans to submit the full paper to a scientific journal shortly; the manuscript and corresponding data will be made available upon submission to the journal.

PML Applications provides independent and impartial scientific consultancy services as the commercial subsidiary of Plymouth Marine Laboratory (PML). Planetary Technologies contracted PML Applications to monitor carbon, pH, nutrients and suspended particulates in order to a) quantify CDR and b) monitor pH and suspended particulates.

Further detailed questions on Planetary’s foundational science. 

We received a set of questions from our community engagement sessions around our foundational science. In the spirit of transparency, we have included all discussion, questions and our responses on this page.

How does Planetary think of the monitoring requirement suggested from this scientific paper

A scientific paper on the potential impact of ocean alkalinity CDR measures on the ecology of the ocean is about to be published. It offers some fascinating results, namely that synthetic minerals have gigaton-scale potential to draw down carbon in the ocean with minimal environmental impacts, but naturally occurring alkaline minerals such as basalt are relatively ineffective, and could have some catastrophic implications for ocean’s food chain and biological pump. Some have commented that if a project is planning to add a mineral to the ocean, the project should also monitor how the particles respond to “marine snow” – a part of the ocean’s biological pump. 

It is very unlikely that our addition of Magnesium Hydroxide in Cornwall will impact marine snow formation and additional accumulation on the seafloor, especially given the nature of our study – which is so small.

Given the very tiny, and likely undetectable, particle loads we will add to seawater, it will be almost impossible for those particle loads to directly lead to formulation of marine snow, particularly at the early stages of our deployments.

We also know that the Cornish coast provides the ideal conditions for this kind of study. Because the water is shallow and turbulent – and the currents keep water near the surface for a long time – it is very unlikely that any accumulation of magnesium hydroxide on the seabed would occur.  

Regardless, scientific integrity, transparency and accountability are at the heart of what we do. That’s why we have an extensive monitoring program for the seafloor and sedimentation, and if we identify any unusual precipitation, for any reason including marine snow, we will pause the trial and examine the situation before proceeding.

In the meantime, we will continue to work with scientists and experts around the world on researching and investigating potential interactions with marine snow and the biological pump.

Lead Responder: Dr. Will Burt
Chief Ocean Scientist