Heirloom uses limestone to remove CO₂ from the air.
- Direct air capture
- Offtake - 2023
- Total contract value
- Brisbane, CA, US
- Delivery timeline
- 2025 - 2030
In Heirloom’s process, crushed limestone is heated to remove the CO₂ stored in the rock and then spread on stacked trays and hydrated to expose the now highly reactive rock to the ambient air. Over the course of three days (as opposed to the months to years it would take in nature) the minerals absorb CO₂.
They’re then moved into an electric kiln and heated for a few seconds, resulting in a stream of CO₂ that can be paired with any type of permanent storage. The same crushed rock is then redistributed back onto the trays, and the cycle begins again.
Frontier buyers’ total offtake is $26.6M for 26,900 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. This agreement includes key milestones that must be met prior to delivery, including sharing a community benefits plan, presenting results from their FEED study, signing a PPA for renewable energy on their local grid, and securing permits for storage.