C3 snaps up Efficiency 2.0 to tackle utility customers

Watch out Opower. Carbon and energy software player C3 — the quiet firm started by Thomas Siebel and which counts Condoleezza Rice as a director — has acquired another energy software startup Efficiency 2.0.

Thomas Siebel Unveils Customers, Scale of C3

Thomas Siebel unveiled customers and features of his stealthy carbon software company C3 at the Fortune Brainstorm Green event. It’s not a software product, said Siebel, it’s a $150 million effort that will take a decade to build and is more like a division of SAP.

Siebel, Condi Rice-Backed C3 Looking to Raise Close to $50M

Energy resource management startup C3 has some major names from the tech and policy world in its corner, and is amassing close to $50 million in funding, according to an SEC filing today, but the company is still largely in stealth mode.