A Silicon Valley startup, Calera has aimed to configure its operations around repurposing CO2 as concrete. It has received funding from Khosla Ventures Venture Capital, the Department of Energy and Hercules Capital. The company, founded by Brent Constanz (now the CEO of Blue Planet), received a large amount of funding early on, including $50 million from Khosla, but there has been little news about the company in recent years. The company has reportedly pivoted from mixing CO2 in cement to “using the material to make fiber cement boards used in bathroom tile backing or exterior siding.” Last decade, when Calera touted its technologies and received funding from the DOE, one prominent scientist criticized it, alleging that its operations would actually increase CO2 emissions.