Calera is dedicated to reversing global warming by capturing and storing greenhouse gases in built environment.

Los Gatos, CA
VC-Funded Company
Green Building

News stories: Khosla-Backed Calera Scoops Up $19M for Carbon Recycling. July 22, 2010.

The Calera story really began in 1984, when Brent Constantz was a graduate student at the University of California at Santa Cruz. Constantz had a coveted National Science Foundation Predoctoral Fellowship grant, entitled "The Skeletal Ultrastructure of Scleractinian Corals”, allowing him to study coral growth mechanisms in the Caribbean and the Indo-Pacific, as well as the deep sea and temperate latitudes. His insights about the physiochemically-dominated skeletogentic mechanism of reef coral led to Norian SRS, a market leading biomimetic biomineral bone cement used today in most operating rooms that perform orthopedic surgery. Before he became aware of the global epidemic of osteoporosis, he had been interested in co-opting coral growth mechanisms for creating large structures in tropical oceans out of ‘mother-of-pearl’ or synthetic limestone. His vision was that these mechanisms would be lifted out of the sea in modules and assembled into massive structures in the built environment, like buildings and bridges.

Constantz started his college career in 1976 at U.C Berkeley in architecture, mostly to play on their NCAA championship water polo team. He transferred to UC Santa Barbara in 1978 to a double major in Aquatic Biology and Geological Science, after seeing scanning electron micrographs of the elaborate mineralized structures of diatoms (siliceous marine plants), which he saw as the most fantastic architecture. During the two decades (1987 – 2007) following his post-doctoral studies at the USGS and Fulbright at the Weizmann Institute, his primary attention was focused on medical applications of biomineralization. Having initially met Vinod Khosla in 1987, and having learned of Khosla’s interest in clean technology, Constantz contacted Khosla in 2007 with his idea about a new "green cement" to replace the carbon-intensive Portland cement, the third largest source of anthropogenic carbon dioxide. Khosla saw the value of the idea immediately and Khosla Ventures funded Calera after a couple of meetings, without even a business plan or slide presentation. Within a few months, Constantz had assembled a team that was making carbonate cements from seawater, hauled over from Santa Cruz to their facility in Los Gatos in a water trailer. In October 2007, while Khosla was visiting the Los Gatos laboratory, the team noted that lack of carbon dioxide in the seawater was limiting the reaction, and there was a need for more carbon dioxide. An experiment was in progress, bubbling carbon dioxide through the seawater, and it was noted that the yield increased eight-fold. Constantz turned to Khosla and asked, “Where can we get large quantities of carbon dioxide?”

The name Calera is Spanish, meaning lime-kiln (n.) or Calcareous (adj.). Founding the company, Brent Constantz named it Calera because he was studying the Calera Limestone in the Coastal Ranges of California as one of his academic interests at Stanford. The ‘Calera’ is a 100 million year old pelagic limestone that rests on an exotic terrane which originated from about 10° latitude near the equator and was displaced northward along the western margin of North America, several slivers of which today extend from New Almaden, south of San Jose, to Moss Beach, near San Francisco. The Calera is unique in that it is not bedded like most deep water limestones and does not contain many fossils, except for calcareous plankton from the open ocean. Instead, it appears to be the product of inorganic precipitation of calcium carbonate from hydrothermal vents expressing hot water from the Earth’s mantle into the deep sea. Supporting evidence for this interpretation is seen near Ridge vineyards in Cupertino, where the Calera rests directly upon pillow basalts, which result from fresh basalt extruding at the mid-ocean rises, creating new oceanic crust.

Ridge Vineyards is known for its great Zinfandels. In the 1970’s—the early days of great California reds—Ridge winemaker Paul Draper interacted with Josh Jensen of Calera Winery, near Hollister, to set the stage for the great reds produced from this chalky, limestone terroir. Calera Wine Company has an old Spanish cement kiln on the property for which it is named. The winery itself, however, actually rests on Paleozoic marble.

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