NEW YORK (CNNMoney.com) - No. 1 natural foods grocery chain Whole Foods is expected to announce plans that will earn it the distinction of becoming the top corporate buyer of renewable wind energy credits in North America, according to a report published Tuesday.

USA Today reported that the move also makes Austin, Texas-based Whole Foods (Research) the only Fortune 500 company to purchase renewable energy credits -- which subsidize the production of energy from renewable resources such as wind -- to offset 100 percent of its projected electrical energy use for 2006.

One credit represents one megawatt-hour of electricity from renewable resources, the report said. Producers of such energy sell the credits through brokers and the proceeds help offset the additional cost of generating electricity that way rather than by burning fuels such as coal.

The newspaper said the move by Whole Foods comes at a time when more Fortune 500 companies are trying to project a "greener" image, including General Electric (Research), whose CEO Jeffrey Immelt recently pledged to decrease pollution and double R&D spending on cleaner technologies.

"From a branding perspective, it's a stroke of genius," the report quoted Barbara Brooks, president of the Strategy Group, as saying. "It shows they understand where their customers are coming from not only nutritionally, but environmentally."

Wind energy is the fastest-growing source of electricity in the United States, the report said. Whole Foods' purchase could help avoid more than 700 million pounds of carbon dioxide pollution in 2006, according to the Environmental Protection Agency.

But the report points out that Whole Foods isn't doing this altruistically. Most grocery stores are big users of energy, the report said. As the 180-store chain grows, the company is increasingly being asked by its environmentally-conscious customers and employees about what it's doing to limit energy waste, the newspaper said.

Whole Foods declined to say what it spends on utilities or what it's paying for the wind credits, the newspaper said. However, the report said the company's purchase equals 458 million kilowatt hours, and it gets no tax advantage for it.