Planetary
Planetary adds alkaline minerals to the ocean to capture CO₂ and counter acidification.
- Pathway
- Ocean alkalinity enhancement
- Contracted tons
- 115,211
- Track
- Offtake - 2025
- Total contract value
- $31.3M
- Location
- Halifax, Nova Scotia, CA
- Delivery timeline
- 2026 – 2030
The approach
Planetary’s process involves careful addition of dissolved alkaline minerals, such as calcium oxide (CaO) or magnesium oxide (MgO), into coastal surface waters. This process boosts the ocean’s natural ability to drawdown carbon by converting dissolved CO₂ into stable bicarbonate ions, which are durably stored in the ocean for over 10,000 years.
They use existing coastal facilities—like power plant cooling water outfalls—to ensure quick and effective integration without the need for massive new infrastructure investment. Unlike biological approaches, OAE works through the ocean’s chemical buffering system, avoiding disruption to biological carbon cycling and food webs.
The case for Planetary
It has a path to <$100/ ton and gigaton-scale removal. OAE, including through alkaline mineral addition, offers a path to extremely low-cost carbon removal, with a potential to remove billions of tons of CO₂ annually at a price of $50-160/ ton¹. Planetary’s path to lower cost is contingent on 1) switching to lower-cost alkaline feedstocks and 2) co-locating facilities near these feedstock sources to cut transportation costs.
Environmental monitoring is baked in at every step of the process. The team manages the end-to-end process with rigorous safety controls: 1) they conduct extensive screening of feedstocks to detect and avoid harmful contaminants, 2) they use a network of sensors to monitor the discharge water and surrounding ecosystems in real-time, and 3) they have established a “stop trigger” plan to immediately halt dosing if any measurement exceeds permitted safety thresholds.
Planetary’s MRV sets a high bar for measuring open-system pathways. Measuring carbon removal in the ocean is challenging because its efficacy depends on the alkaline materials dissolving in the water. Planetary dissolves the alkaline minerals before releasing them in the ocean. This removes the uncertainty around where and at what timepoint the material dissolves to do its job. Planetary then uses sensors and validated computational models to measure the effects of the added alkalinity, including on air-sea gas exchange.
It delivers co-benefits for ocean ecosystems. By locally raising pH and carbonate saturation levels, Planetary's OAE approach helps counteract local effects of ocean acidification. This improves conditions for marine calcifiers like oysters, shrimp, lobsters, and crabs, benefitting not only the aquaculture and fishing industries but also natural ecosystems. Planetary is conducting research to quantify these benefits in partnership with academic institutions (Dalhousie University) and local communities (First Nations, environmental groups, municipal leaders, and fisheries).
The team will make project findings publicly available: This offtake includes binding commitments to share data in line with FAIR data principles and the Carbon to Sea data protocol.
Pricing and delivery
The total offtake amount from Frontier buyers is $31.3 million for 115,211 tons. The price accounts for both the removal itself as well as measuring, reporting and verifying (MRV) that each ton is safely and permanently stored.
