DAVIS, United States — Media company AlwaysOn announced its first GoingGreen 100 Top Private Companies, a list of the world's top 100 greentech innovators that are helping the corporate world become more environmentally friendly.

The announcement coincided with a conference presented by GoingGreen and the University of California at Davis. GoingGreen's editorial panels screened hundreds of private companies to choose the winners. Entrants were nominated by venture capital firms and green tech insiders.

"The AlwaysOn GoingGreen 100 companies will accelerate the global movement to a more sustainable environment," Tony Perkins, founder and editor of AlwaysOn, said in a statement. "The ideas and innovation we saw as we reviewed hundreds of clean technology companies will be foundational to the next wave of economic growth in California and beyond."

The winners were chosen based on five criteria: innovation, market potential, commercialization, stakeholder value creation and media attention or "buzz."

They have a hand in transforming trillion-dollar industries, such as the worldwide energy, water, agriculture, transportation, construction, manufacturing and resource recovery establishments.

The overall winner was GridPoint Inc., an innovator of a smart grid platform that links the interests of utilities, consumers and environment.

Other winners included Tesla Motors, which is close to releasing a luxury plug-in hybrid vehicle; A123 Systems, a high-power lithium battery producer working with GM to produce the Chevy Volt; Ze-Gen, a developer of technology that converts solid, construction and demolition waste into synthetic gas and electrical energy; and Verdiem, which makes energy efficiency software.