FAQs

We, along with our third party scientific and academic partners, are confident that these projects are safe for humans, animals, and the marine environment – from plankton to whales, and everything in between. 

Marine safety is of paramount importance to every member of Planetary’s team, and we approach all research with an abundance of caution. Our precautions are too lengthy to answer in a brief FAQ, but we encourage you to visit our safety page to read in detail about how we have built safety into our process and our operations.

To summarize:

• Magnesium hydroxide has safely been ingested by humans and commonly used in wastewater treatment for decades.
• Scientific testing indicates the compound is safe for aquatic animals, and there is no evidence that magnesium hydroxide is bio-accumulative.
• Our studies are conducted for a short duration, and at a low concentration, below all safety and regulatory limits. 
• We monitor our alkalinity and the receiving waters before, during, and after a study begins to ensure there are no unforeseen impacts on the ecosystem. (More information on that ocean monitoring is available here.

This question strikes at the moral implications of carbon removal – and is a difficult question to address fully as a single question. Mike Kelland has therefore taken this moment to offer a more detailed response as a blog post.

This storage timescale is widely accepted by the scientific community and policy makers and is considered one of the main attractions for this type of carbon removal compared to other less permanent approaches that are currently proposed. 

Our planet and atmosphere form a closed environment. Carbon continuously cycles in and out of the land and sea – into the atmosphere and back again. The ocean plays a very important role in this cycle as it stores the vast majority of the carbon on earth (approximately 34,000 metric Gigatons or 34,000 Gt) in the form of dissolved, alkaline carbon seawater. In addition, we also know that this carbon is stored out of the atmosphere for very long periods of time. We know this by measuring how much alkaline carbon the ocean intakes annually, and by verifying how much of this carbon is precipitated out annually. The net result is approximately 0.3 Gt carbon loss from the alkaline carbon pool. From this we can calculate the mean time that the carbon will be locked away, which is called residence time: 

Residence time of carbon = (total carbon stored) (net loss of carbon/year)
34,000 Gt / (0.3 Gt/year) = 113,333 years

We round this down to 100,000 years to be conservative and to account for uncertainties in the calculation. 

Our process captures CO2 and converts it to this same long-lived alkaline carbon. Doing so will allow the ocean to plan the important role of safely removing and sequestering carbon from the atmosphere. While the chemistry involved in this form of carbon storage is a bit complicated, it is also well published and well understood.

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

For more information on how we monitor for biological impacts, please see our Ocean Monitoring and Safety pages.

While exact details of monitoring will depend on individual sites and local partnerships, we have published a blog post to outline our monitoring process before, during, and beyond our study at Cornwall.

How do you source your alkalinity? How do you intend to source it as you scale up?

(…) From a cost and efficiency standpoint, local sources of MH are preferred. Every mile of transport creates emissions which reduce the total net removals of our OAE process and increase costs. Transportation emissions depend on the mode of transport. For bulk product shipments, the emissions, from lowest per-tonne mile to highest are long-haul ship, short-haul ship, rail, truck, and plane. This means that the most viable sources are those which are coastally located. It also means that removals can generally be achieved at various places around the world based on these coastal sources. Assuming that our trials are successful, our goal is to source MH as near to the point of addition as possible. While none of the following sourcing arrangements are currently in place, we see the following potential sources: 

Provision of a carbon-capturing kiln to existing MH producers. 

Development of new brine processing from the use of UK limestone with a carbon-capturing kiln. 

Until these processes are developed and deployed, we’ll use MH from other sources on a per-project basis that provides a net carbon benefit despite transportation emissions. 

Question archived as this goal no longer reflects our current timeline.

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.

Ultimately, Planetary’s goal is always to use the nearest and lowest-carbon source of safe alkalinity. Each project site is unique, and careful incremental trials of our process are required before we can scale up in any substantial way. That’s how we keep things safe. As a result, it doesn’t typically make sense to invest in building a new, low carbon supply of alkalinity nearby until we’re gone through an incremental scale up and have the “demand” that would make that large investment worthwhile. That means that at low scales, we need to rely on the sources that are available today. 

There are several pathways to produce magnesium hydroxide (MH) for carbon removal: 

• MH can be mined directly from the ground as brucite, its mineral form. Brucite is relatively scarce in a pure form, so the cost can be high, but it has a low carbon footprint as it requires little processing. Our first trials use brucite, since it’s available today without needing large infrastructure to be built. 

• It can also be produced through the addition of slaked lime (Ca(OH)₂) to brines such as seawater. If the slaked lime is produced from limestone using a kiln that captures CO₂ emissions, and the brine does not contain carbon or the carbon is kept in the brine through the process, this can be a suitable MH source for carbon removal. This could ultimately be a lo-cost and globally abundant source, since limestone is so prevalent, once carbon-capture kilns are more commonly in use. 
• MH can be produced through its extraction from magnesium silicate rock. Planetary is pioneering this process and it will be several years before it gets to scale. This process, though, has the highest potential because magnesium silicate is globally abundant and is produced at a massive scale as a waste in nickel, lithium, and other mining activities. 

From a cost and efficiency standpoint, local sources of MH are preferred. Every mile of transport creates emissions which reduce the total net removals of our OAE process and increase costs. Transportation emissions depend on the mode of transport. For bulk product shipments, the emissions, from lowest per-tonne mile to highest are long-haul ship, short-haul ship, rail, truck, and plane. This means that the most viable sources are those which are coastally located. It also means that removals can generally be achieved at various places around the world based on these coastal sources. Assuming that our trials are successful, our goal is to source MH as near to the point of addition as possible. While none of the following sourcing arrangements are currently in place, we see the following potential sources: 

• Development of the Planetary process to utilise magnesium silicate waste from mining operations (such as in Cornwall).
• Provision of a carbon-capturing kiln to existing MH producers. 
• Development of new brine processing from the use of UK limestone with a carbon-capturing kiln. 

Until these processes are developed and deployed, we’ll use MH from other sources on a per-project basis that provides a net carbon benefit despite transportation emissions. 

We have a multi-step process and several safeguards in place to ensure that the antacid added to the ocean outfall is fully compliant with local regulatory standards like the UK Environmental Quality Standards (EQS) or the requirements of Canada’s Fisheries Act. 

First, we work with mineral suppliers to select products that are known to be safe in multiple applications. For example, one of the reasons that we have chosen Magnesium Hydroxide (MH) for projects 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 local regulation for coastal waters. This allows us to predict how much alkalinity can be added as a percentage of the flow rate, as well as how much can be added over a given period while complying with these standards. 

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

Throughout the addition phase, we will be taking samples of the treated water upstream and downstream of the addition point to measure any baseline impurities in the outflow, as well as any changes resulting from the addition. 

As a final safeguard, we work with independent scientific consultants 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.