What does a lonely stretch of wheat fields along the southeastern border of Washington State have to do with the work of the Hewlett Foundation?

It’s the home of the Stateline Wind Energy Center, the nation’s largest wind farm and one of more than a dozen sources of clean energy from which the Foundation has agreed to purchase so-called “green tags” to offset the carbon emissions that it generates in the course of its philanthropic work.

The Foundation has committed to purchase $130,000 in green tags over the next three years to compensate for an estimated 1,000 tons of carbon dioxide emissions it generates annually from electrical and natural gas consumption at its building and through staff commutes and air travel. The commitment means that the Foundation is supporting the generation of clean, renewable energy in an amount proportional to the carbon emissions generated through the consumption of other sources of energy.

“This is bringing our work home with us in the best sense of the term,” says Hal Harvey, director of the Foundation’s Environmental Program. “It’s also part of a sea change in awareness about how we all contribute to the problem and can take action to help.”

The purchase of green tags and other instruments to offset carbon emissions is a growing phenomenon. Among the many entities that have done so are the Olympics, the Super Bowl, the Whole Foods supermarket chain, the World Bank-even rock bands like the Rolling Stones and Coldplay.

The Foundation estimated its “carbon footprint” with the help of a booklet and spreadsheet available at the Web site of the World Resources Institute, an environmental think tank. The tools are entitled “Working 9 to 5 on Climate Change: An Office Guide” and can be downloaded at http://www.wri.org/climate/pubs_description.cfm?pid=3756. At the end of three years, the Foundation will take a new inventory of its carbon emissions and decide whether to buy more carbon offsets and in what quantity.

The green tags were purchased through the Bonneville Environmental Foundation, a Hewlett Foundation grantee founded in 1998 to support watershed restoration programs and develop new sources of renewable energy. On the Hewlett Foundation’s behalf, the Portland, Oregon-based Bonneville Foundation will purchase the green tags from a dozen wind farms and several solar power projects throughout the United States and Canada, and assure that a green tag is issued for each megawatt hour of electricity generated at a designated facility.

The Stateline Wind Energy Center is anticipated to be the single largest source of clean energy that the Hewlett Foundation is purchasing under the agreement. All told, Stateline currently creates enough wholesale electricity to power some 70,000 households.

In effect, the revenue generated by the green tags helps underwrite the higher up-front costs of renewable energy generation compared to that of energy generated by the burning of fossil fuels. As those costs are amortized, the cost of the renewable generation comes down. And in the meantime, every megawatt of power generated from the renewable sources displaces power from fossil fuel plants. Any remaining net revenues are then reinvested in the next generation of renewable energy.

It’s not just foundations and businesses that can offset their carbon emissions by investing in green tags. The Bonneville Foundation Web site has a carbon calculator tool (https://www.greentagsusa.org/GreenTags/index.cfm) that lets homeowners calculate the carbon emissions of their activities and buy green tags through the site.

The purchase of the green tags is the most recent example of the Hewlett Foundation’s intentions to go green. In 2002, the Foundation moved into its current headquarters, the first commercial building in California-and only the fifth in the nation-to receive gold-level certification from the U.S. Green Building Council’s Leadership in Energy and Environmental Design green-building rating system. The Foundation earned this recognition by addressing a wide range of building-related environmental issues concerning site design, water and energy efficiency, materials and resources and indoor environmental quality.