General Motors Ventures LLC will invest $6 million in zero-emission commercial transit bus maker Proterra, the company said in a statement on Monday.

GM Ventures is part of an investment group led by venture capital firm Kleiner Perkins Caufield & Byers that will invest a total of $30 million in the bus manufacturer. The investment is part of its mission to invest in next-generation technologies that support innovation in the global transportation industry, the statement added.

This equity investment further demonstrates GM's commitment to electric propulsion and supports our commitment to identify and invest in technology solutions that help advance the global transportation industry, said Jon Lauckner, president of GM Ventures.

This investment allows Proterra to complete federal validation testing of its bus, roll out additional pilot fleets and complete initiatives to significantly reduce costs and increase volume production at its Greenville, S.C. manufacturing plant, which will have the capacity to produce 400 buses annually. 

With the support of GM's automotive expertise and technology leadership, we can achieve a better, cleaner future for public transportation, said Jeff Granato, president of Proterra. We are proud to have General Motors on board.

Proterra Inc. was founded in 2004 and is currently manufacturing buses in a temporary plant in Greenville, S.C. near Clemson University International Center for Automotive Research. Proterra's TerraVolt energy storage system consists of 54-72 kWh lithium titanate battery packs that recharge in 10 minutes using the company's roof-mounted Fast recharging system.