NEW YORK ( TheStreet) -- Coal company Peabody Energy ( BTU) is expected to announce its decision to invest in energy start-up company Calera this week, according to the New York Times. Calera's claim to fame is that is has developed technology converting most of the carbon dioxide emission from a coal or gas-fired power plant into calcium carbonate, which can then be prepared for use in wall or highway construction. If Calera can replicate this process on a grander scale, companies could ultimately do away with costly carbon-sequestration systems that would need to be built next to these power plants, "and it might actually make the heretofore specious notion of 'clean coal' a possibility," Times' columnist Thomas Friedman writes. Calera is currently the pet project of Vinod Khosla, co-founder of Oracle's ( ORCL) Sun Microsystems, and an avid supporter of clean energy start-up companies, the Times reports. "If this works," Khosla said, "coal-fired power would become more than 100% clean. Not only would it not emit any CO2, but by producing clean water and cement as a byproduct, it would also be taking all of the CO2 that goes into making those products out of the atmosphere." Peabody stock is up 0.6% at $49.50 in pre-market trading. -- Reported by Andrea Tse in New York Follow TheStreet.com on Twitter and become a fan on Facebook.