Many companies are learning they can be both pro-business and pro-environment without hurting the bottom line.   In fact, for some, it's been quite profitable. 

Being environmentally-friendly is not about global warming or reducing emissions.  For some companies it's about giving customers exactly what they want.

General Electric says sales of its energy efficient products such as light bulbs and cleaner locomotive engines topped $10 billion last year.   Gary Sheffer is a spokesman for the multinational conglomerate. He says that figure is double from the year before. "We're sold out of our wind products and we're pretty much sold out on some of our most efficient aircraft engines."

Even Wal-Mart has discovered that environmentally smart products sell.  The retailer is now the world's largest consumer of organically-grown cotton. 

Fred Krup is with the non-profit group, Environmental Defense, says that companies are becoming more environmentally conscious. "Companies are seeing that increasingly people want more efficient, cleaner products, so the smart companies are looking ahead and seeing there are profits to be made here."

And its not only about selling cleaner products.  Chemical manufacturer Dupont switched to more energy efficient technologies 10 years ago to reduce its plant emissions. It saved more than $2 billion in the process.

FedEx ships packages around the world. It also found a way to save money while easing the strain on power grids. FedEx environmental director Mitch Jackson says its airport operations in Oakland, California, run primarily on solar power.  "We will have a clean, renewable supply of power at a consistent price, free from the sun for 30 years."

The greening is also happening in corporate offices.  The futuristic Hearst Tower in New York is lit entirely by the sun.  The building's waterfall was designed to cool the lobby.

And over at the new Bank of America building site -- cafeteria scraps will be converted into methane to supply power to the building.

Experts say the green buildings will save millions of dollars in energy costs every year.