Not so long ago, the word "green" was more synonymous with the almighty dollar than with sustainability. Environmentalism was the milieu of a certain harebrained, hippie-ish fringe element. The mere suggestion of energy conservation was met with near-universal eye rolling, as if an entire culture was hearing a curmudgeonly father figure barking for the thousandth time, "Turn off the lights! Do I look like I'm made of money?!"

Until recently, even in circles where rudimentary efforts at sustainability were normally observed, hotel stays remained an excuse for unabashed excess. Guests used fresh towels at every available opportunity, left the television blaring even when they were away from their rooms, plunged the air conditioning to icily delicious lows and delightfully consumed every miniature freebie that they could get their hands on.

Even as the cultural tide began inching toward sustainability with the gas crisis of the 1970s, hotels remained a last bastion of wanton consumption. In his book "Global Energy Innovation: Why America Must Lead," author Woodrow W. Clarke notes that luxury hotels were the worst offenders. He writes, "At hundreds, sometimes thousands, of dollars a night for a room, a luxury hotel cannot trim back on customer service...For this reason, luxury hotels have been particularly resistant to change, due to fear that once word gets out that a hotel is cutting back, it will lose its clientele."

Nevertheless, all signs point to the fact that the hotel industry is getting greener by the day. A trend that began years ago with environmentally friendly lodges in fragile ecosystems has bloomed into an industry-wide movement that is setting the tone for green building worldwide. Doug Gatlin, the U.S. Green Building Council's vice president of marketing and development, told Forbes Magazine that the hospitality industry has become "a mainstay of the green building movement" [source: Bender].

From power-generating exercise bikes in Copenhagen to simple printed cards asking guests to reuse towels, the hotel industry is experimenting with all kinds of ways to conserve and recycle.