Heirloom is harnessing a geologic approach to catching and holding carbon dioxide in limestone naturally binds to carbon. Heirloom's technology dramatically speeds up the process, cutting it from years to days. The startup operates the only US facility permanently capturing carbon. Even more important than the volume of carbon to be removed is the deal's ability to unlock additional funding and investments to grow Heirloom's business and the sector more broadly.

Microsoft previously invested in Heirloom through its $1 billion Climate Innovation Fund. The new deal represents a financially empowering "bankable agreement."

Heirloom CEO Shashank Samala said: "Bankable agreements of this magnitude enable Heirloom to raise project finance for our rapid scale-up, fueling exponential growth like what we've seen in the renewable energy industry.  The cash flow can facilitate financing needed to build Heirloom's next two commercial sites.