Cleantech companies are getting more green, with Ausra, EPS, and Powerspan announcing big rounds of funding.

Ausra, a developer of large-scale solar thermal systems, raised $25.5 million in fourth round funding. Participants include Khosla Ventures, Kleiner Perkins Caufield & Byers, KERN Partners, Generation Investment Management, and Starfish Ventures. The funding will go toward  expansion.

The company uses its Compact Linear Fresnel Reflector technology to concentrate sunlight and boil water that flows through a tube system, which in turn generates steam that can be used to generate power.

While Ausra focuses more on solar, Powerspan works with pollution control and carbon dioxide capture. The company announced a $50 million fourth round of funding from a bevy of investors.

Returning investors include Angeleno Group, Calvert, FirstEnergy, Fluor, NGEN Partners, The Beacon Group, The Tremont Group, and RockPort Capital Partners. New investors AllianceBernstein, George Soros, Persimmon Tree Capital, and Tenaska Energy also participated.

The money will go toward commercially deploying its ECO2 technology, which the company is testing at a power plant in Ohio. Powerspan plans to get a 120 megawatt demonstration plant up and running by 2012.

A successful commercial launch would mean a 90 percent carbon dioxide capture rate, lowering pollution and providing carbon dioxide for Powerspan to use in “oil recovery operations.”

EPS, an energy intelligence company, covers the middle ground between the other two companies. EPS raised $30 million in second round funding. The round was led by Altira Group, with return backers NGEN Partners and Robeco also participating.

EPS will use the funding to expand its energy and carbon emissions management system, xChange Point, as well as to make acquisitions.