HEIRLOOM CARBON

Shashank Samala was a repeat founder (his previous startup was in the trucking industry) who became obsessed with climate change. He studied the carbon removal space and found that most approaches were either too expensive or too slow.

Then he discovered enhanced weathering — the idea that certain minerals naturally absorb CO2, and you can speed up the process dramatically. Limestone was the key: when you heat limestone (calcium carbonate), it releases CO2 and becomes calcium oxide.

When you expose calcium oxide to air, it reabsorbs CO2 from the atmosphere. Heirloom built a system that industrializes this natural cycle, using renewable energy to heat the limestone and outdoor mineral beds to reabsorb CO2.

The company launched in 2020 and opened the first commercial direct air capture facility in the US in 2023 in Tracy, California.

Heirloom sells carbon removal credits. Companies that want to offset their emissions pay Heirloom to permanently remove CO2 from the atmosphere.

The CO2 is captured, verified by third parties, and stored underground in geological formations. Customers include Microsoft, Stripe, JPMorgan, and the US government (through the Department of Energy).

Heirloom also won a $600 million award from the DOE's Regional Direct Air Capture Hubs program to build a large-scale facility in Louisiana. Revenue comes from pre-purchase agreements for future carbon removal tons.

Heirloom's direct air capture system uses limestone-based carbon mineralization. Their mineral beds expose calcium oxide to ambient air, absorbing CO2 over days.

The enhanced limestone is then heated in kilns to release concentrated CO2 for permanent underground storage. Their Tracy, California facility was the first commercial DAC plant in the US.

The planned Louisiana facility will be one of the largest carbon removal operations in the world.

Heirloom's growth strategy is aggressive scaling. Their Tracy facility was a proof of concept.

The Louisiana hub (DOE-funded) will be orders of magnitude larger. They're focused on driving down the cost per ton of CO2 removed — currently around $600/ton, with a target of under $100/ton at scale.

They've secured forward purchase agreements from major corporations, providing revenue visibility. They're also building partnerships with geological storage providers to ensure permanent CO2 sequestration.

Cost is the existential challenge. At $600/ton, carbon removal is far too expensive for most applications.

Heirloom needs to achieve dramatic cost reductions through scale, engineering improvements, and cheaper renewable energy. The technology also requires significant energy input (heating limestone to 900°C), and the carbon math only works if that energy comes from renewables.

Competition from other carbon removal approaches (Climeworks' direct air capture, ocean-based methods, biochar) is intensifying. And the market for carbon removal credits depends on corporate willingness to pay and potential government mandates, both of which are politically uncertain.

Breakthrough Energy Ventures (Bill Gates) is a lead investor. Ahren Innovation Capital, Carbon Direct Capital, Lowercarbon Capital, and Microsoft's Climate Innovation Fund have also invested.

The US Department of Energy committed up to $600 million for the Louisiana DAC hub. Stripe and JPMorgan are both offtake customers and indirect supporters through their carbon removal procurement programs.