Heirloom

The Approach

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.

The Case for Heirloom

DAC offers a promising path to permanent CDR that meets majority of Frontier’s criteria — durable, measurable/verifiable, small footprint. The main drawback remains high capture costs from energy requirements and upfront capex.

Heirloom’s innovation combines inexpensive, abundant limestone with modular processes. Sorbent performance has been achieved; they are now focused on engineering and operational scaling of limestone tray processing.

A unique DAC approach diversifying field bets. Uses inexpensive natural material, modular processes, and renewable-powered electric kilns eliminating fossil fuels.

Cost reduction relies on capex/opex declines through simplicity, economies of scale, and operational excellence. Capex reduction via manufacturing scale, plant lifetimes, and capital costs. Opex declines from labor, maintenance, and energy reduction — methods demonstrated in solar/wind industries.

Pricing and Delivery

Frontier buyers’ total offtake is $26.6M for 26,900 tons. The price accounts for removal and measuring, reporting and verifying permanent storage. Agreement includes milestones: community benefits plan, FEED study results, renewable energy PPA, and storage permits.