The U.S. Environmental Protection Agency has recognized Bates College for its leading role in the use of electricity from renewable sources, President Elaine Tuttle Hansen has announced.

The EPA has included Bates in its Green Power Leadership Club, which distinguishes institutions whose power purchases meet or exceed a certain proportion of renewable power. To qualify for the club, a consumer of Bates’ size would need to buy at least 18 percent of its electricity from renewable sources. But nearly 96 percent of the power that Bates purchases comes from such sources, including biomass generation, small hydro and wind power facilities.

Bates is the largest purchaser of green power both within the New England Small College Athletic Conference and among all small, private liberal arts colleges in the EPA’s Green Power Partnership, a voluntary program helping to increase the use of green power.

Bates made the switch to green power in 2005. Through the energy brokers Constellation New Energy and Sterling Planet, the college purchases more than 13.1 million kilowatt-hours of renewable electricity annually. In effect, the EPA estimates, that prevents nearly 18.4 million pounds of carbon dioxide — the equivalent of the CO2 emitted by an estimated 1,800 cars — from entering the atmosphere over the next year.

“As an educational institution, Bates has a longstanding commitment to both inform its community about the environment and reflect environmental responsibility in its policies and actions,” said Hansen. “We look for ways to be good stewards of all our resources, and the purchase of green energy is one more way we can live up to this commitment.”

Much more information appears on the EPA Web site.

Seniors at Bates typically select a fund-raising project during their last year at the college, and the class of 2006 decided to help defray the added costs of renewable electricity. The drive raised $19,903.83 for the project, more than a quarter of the difference between the 2005-06 costs of green power and electricity from conventional sources.

Two hundred and sixty-six seniors, or 67.5 percent of the class, took part, along with parents, other students and alumni. David Barlow, a Bates trustee, member of the college’s class of 1979 and chairman and CEO of the Massachusetts-based Molecular Insight Pharmaceuticals, made matching gifts that totaled $10,000.

The senior gift co-chairs were Tracey Begley of New York City and John “Jamie” Nissen, originally of Cumberland and now a Boston resident. Other class leaders instrumental in the effort were Erin Culbreth of Montclair, N.J., and Nicole Moraco of Bedford, N.Y., members of a student team working with the college’s alumni office; and class co-presidents John Phelan of Washington, D.C., and Katharine Nolan of New York City.

“Batesies can pride themselves in ranking first among their peers in the New England Small College Athletic Conference” in the EPA listing, Phelan said. “We hope our efforts will contribute to future generations’ leadership in addressing the looming energy crisis in a progressive way.”

Bates is working on a three-to-five year strategy for implementing initiatives that will lighten its impact on the natural environment. Current initiatives run the gamut from a food-waste composting program recognized by the EPA to the use of biofuel to heat certain residential buildings.

Notably, a student residence and a dining facility now being built at Bates reflect an awareness of environmental sustainability in both their design and construction practices. Both facilities conform to sustainability standards equivalent to the “silver” certification of the United States Green Building Council’s Leadership in Energy and Environmental Design standards. (LEED registration and documentation were not performed.)

“Green” features in the construction process and the structures themselves include mandated recycling of construction waste; energy-efficient room design and utilities systems; stormwater management systems; low-emitting building materials; and the use of wood that’s recycled or certified “green” in the interiors.

This year, in one fell swoop, the 49 students in Econ 222 quadrupled the amount of sulfur dioxide (SO2) that Bates is keeping out of the nation’s air. A $1,200 challenge grant from an environmental organization in Colorado spurred the students to submit winning bids for nine permits in the annual U.S. Environmental Protection Agency SO2-allowance auction.

Thanks to the Community Office for Resource Efficiency, in Aspen, and matching funds from supporters on campus, the students boosted Bates into the top ranks of colleges and universities successfully participating in the EPA auction. By retiring the SO2 permits, the 49 students will prevent the emission of an additional nine tons of this pollutant created by coal-burning power plants.

“This equals the amount of SO2 that would be emitted if you were to leave 3,600 100-watt light bulbs burning for one year straight,” says Lynne Lewis, associate professor of economics and the originator of the college’s annual bidding effort.

Under the 1990 Clean Air Act Amendments, coal-burning utilities are required to have emissions permits. These permits are tradable, and the emissions-allowance auction held each March by the Chicago Board of Trade disposes of some 250,000 allowances.

The Bates students bid $292 for each of the permits in this year’s auction, held March 22. The bid brought to 12 tons the amount of SO2 that the two sections of Lewis’ “Environmental Economics” have retired since 2001.

Since the auctions began, in 1993, dozens of educational institutions from grade school through graduate school have bought and retired permits. The University of Maryland School of Law and affiliated organizations have accumulated by far the most, at 75. Bates is in second place, with 12, and the University of Michigan Law School and affiliates third, with 9.

The challenge grant that quadrupled the students’ total appeared after CORE Executive Director Randy Udall read about Bates’ success in the auction process.

“He asked if our class could match his $1,200 and buy a total of eight permits, as well as educate others about the program,” Lewis explains. “My students designed informational fliers, sold T-shirts that they designed and had a booth in Commons,” the college’s dining hall.

Several campus organizations and many individuals at Bates contributed to the grant-matching drive. “We sold SO2 by the pound,” Lewis says. “Five pounds for a buck — you can’t beat that!” In the end, the students even came up with enough money to top Udall’s challenge by one permit.

Every year, Lewis’ students study past auctions and current markets, and then try to estimate what the price will be. She says, “I believe in learning by doing. We spend a lot of time learning about economic incentives for pollution control — what they are, how they work, when they are most effective, and so on. To tie this exercise in with what we’re learning in the classroom is a phenomenal experience.”

“It’s really exciting to be able to participate in an actual auction,” and the CORE challenge took the excitement to a new level, she says. “I’m really proud of my students. They worked hard on this and bid smart — and we are making a difference, too.”

Because of both its soil chemistry and its location downwind of the nation’s dirtiest utilities, Maine is particularly vulnerable to the effects of sulfur dioxide released by the burning of coal (mercury from the same source is another environmental threat).

“Here’s to economic incentives at work and a little less acid in Maine’s lakes,” said Lynne Bennett, associate professor of economics at Bates College. “This is something students will remember long after they leave Bates College and its text-book economics.”

Students researched the bidding process and proposed a bid amount with each student contributing $5 to the final bid amount of $191 made on March 20. The students learned of their successful bid, listening through a live Internet link, when the Chicago Board of Trade announced the bid results at press conference in late March.