Responsible travel hits the big city.

Since the establishment of the pioneering Lapa Rios Ecolodge in Costa Rica in the early nineties, the term eco-hotel has conjured images of a rustic property set in the rain forests of Central America. Lately, however, more and more hotels are challenging this stereotype by going green in the most unlikely of places—the urban center.

"There is a perfect storm in the hospitality industry right now," says Tedd Saunders, president of EcoLogical Solutions, a Boston-based hospitality consultancy. "Energy prices have shot through the roof just as the architectural world is offering an abundance of efficient new 'green' technologies."

City hotels have responded by adopting a slew of eco-friendly initiatives. Sheraton has introduced fuel cells—small, ultraclean power plants with up to twice the efficiency of fossil fuels—at four urban outposts from New York to San Diego. Hyatt has turned to renewable energy sources (wind, hydro, and solar) in two Dallas locations. Some properties, including a Marriott and a Hilton, are even seeking difficult-to-attain Leadership in Energy and Environmental Design certificates from the U.S. Green Building Council, which can yield significant tax benefits.

At the same time, these hotels are busy touting their environmental innovations to consumers, proving that eco-savvy business is also good PR.