Fossil-fuel companies have been some of the most active in exploring the technology, partly because injecting carbon into fading oil fields has for decades been an established way to boost production.

Now, spurred by huge U.S. subsidies passed last year for capturing and storing carbon dioxide, some of the world’s leading energy companies and a scattering of startups are quietly engaged in a subsurface land grab.

Houston-based Verde CO2, the carbon-capture and sequestration startup founded by Fridge, looks for rural areas close to industrial sites and carbon-dioxide pipelines that have a deep layer of porous rock to inject the liquid CO2, capped by impermeable rock that prevents gas from leaking out.

Little Verde does most of the outreach itself, with Fridge and company president Jon Grimmer holding meetings over barbecue and burgers.

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