Yellowstone Capital Partners, a Houston, Texas venture capital firm, is in the process of raising a new $50 million fund for early-stage cleantech investments, to be called Yellowstone Energy Ventures II.

The firm’s first fund, was distributed between Heliovolt, Solfocus, Solaris Nanosciences, and several other companies. In general, Yellowstone makes investments primarily in energy generation technologies.

General partners Bill Brewer, Rick Owen and Omar Sawaf will continue to manage Yellowstone’s cleantech investments.