Twenty-six students from some of the nation's best business schools have taken on an unusual summer assignment: helping cut corporate America's energy bills.

They belong to an internship program organized by the Environmental Defense Fund that embeds MBA students with companies that want to use less energy, either to fight global warming or just to save money. The Climate Corps interns - drawn from such schools as Yale, UC Berkeley, Columbia and Michigan - will spend 10 weeks hunting for ways to trim the amount of power their host companies need.

"Some of these companies get it, and others? They're trying to get it," defense fund Managing Director Elizabeth Sturcken told the recruits Monday, as they gathered in the environmental group's San Francisco office for the first of three days of training.

"Each of you has the opportunity to change some minds, change some perspectives," she said.

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The Environmental Defense Fund has a history of partnering with businesses to tackle environmental problems. The internship, now in its second year, is the latest extension of that approach. Last year's class of seven interns found enough savings to cut their host companies' energy bills by $35 million over five years.

"Energy efficiency is something every company can do," said Millie Chu Baird, project director for the defense fund. "We wanted to reach as many companies as possible, so we're doing that with interns."

The companies involved - among them Cisco and Intuit - already have an interest in efficiency. Some of them have hired sustainability officers who look for ways to cut energy and water use. Or they've started switching to power-sipping lights and office equipment. The interns will help expand those efforts.

"It's things that have occurred to us, but they haven't reached that tipping point where they've become business as usual," said Jeff Senne, director of metrics and reporting with Sodexo. His company runs cafeterias for businesses, schools and hospitals. Based in Maryland, the company also runs office buildings for other companies.

Sodexo's intern, Katie Schindall from Yale University, will focus on improving the efficiency of the company's Buffalo, N.Y., service center.

"It's a great opportunity to really get into the depths of an organization and say, 'Hey, why don't you try this?' " said Schindall, who will graduate in 2011. "There's so much momentum building right now that if you can come in and make even a small change, other companies will see that."

Schindall and the other interns share an interest in business and a passion for the environment. Many hope to build a career around those twin devotions. Ryan Whisnant, from the University of Michigan, wants to become a sustainability consultant, doing much the same work he'll do for SunGard data systems in Wayne, Pa., during the internship. He studied environmental engineering as an undergraduate before pursuing his master's degree.

"Having the financial skills - that's the way you're going to get managers to listen to you," he said.

Before joining their host companies, the interns spend three days in the Climate Corps "boot camp," getting tips on saving energy in different kinds of buildings and companies. Some sessions focus on saving power in heating and ventilation systems, lighting and data centers. Others focus on financing equipment upgrades. The students also learn how to overcome resistance from company executives and employees who don't want to change.

"Real culture change is what we're after," Sturcken said. "And it's so exciting to see business students who are so passionate about this."