A Colorado cleantech venture, Luca Technologies, filed an S-1 today revealing its intention to go public, and raise up to $125 million (though that number could vary with the receptivity of the market by the time they actually go public). The company stimulates microbes with a "proprietary formulation of nutrients," in already-drilled natural gas wells, which enables the wells to produce more methane, the primary component of natural gas. Luca Technologies owns and operates wells and infrastructure, then sells natural gas into existing markets. Its end users include power utilities, and government entities that use natural gas for power production. Today, Luca's chief executive Bob Cavnar explained...