Washington, D.C. - The U.S. Environmental Protection Agency is asking Fortune 500 companies double their current level of green power purchasing.

The goal of the green power challenge is to exceed 5 billion kilowatt hours (kWh) of green power purchases among participating companies. Five billion kilowatt hours could power more than 400,000 average American homes or avoid the equivalent CO2 emissions associated with more than 680,000 passenger cars each year.

“Through the Read the Fortune 500 Green Power Challenge, we are encouraging the largest companies in the country to purchase more green power,” said Bill Wehrum, EPA’s acting assistant administrator for Air and Radiation. “Purchasing green power is good for the environment, good for the economy and good for our energy independence.”

There are more than 40 Fortune 500 companies participating in the Green Power Partnership; their annual green power purchases currently total 2.5 billion kWh. EPA’s current top five Fortune 500 Green Power Partners are Wells Fargo Company, Whole Foods Markets, Johnson & Johnson, Starbucks and DuPont Company.

This 13-month effort will raise awareness of green power options and help stimulate the development of new green power resources nationwide. Green power is a subset of renewable electricity, which includes resources such as solar, wind, geothermal, biogas, biomass and low-impact hydro. Electricity generation from non-hydro renewable sources currently account for just over two percent of America’s electricity supply.

Corporations who are significantly increasing their green power purchase levels include Cisco Systems Inc., Hewlett Packard (HP), Staples, Starbucks and Wells Fargo & Company.

The Green Power Partnership encourages organizations to purchase green power as a way to reduce the environmental impacts associated with conventional electricity use. The Green Power Partnership is comprised of Fortune 500 companies, local, state, and federal governments, trade associations, and colleges and universities. Green Power Partnership members purchase more than 7 billion kilowatt hours of green power on an annual basis.