The new Genzyme headquarters leads way as many more developers go energy-efficient

One allows access from the hall, and the other opens onto a four-foot-wide walkway on the building's perimeter.An exterior glass curtain wall keeps Galfetti, Genzyme's director of investor relations, safely in that narrow "loggia" space on the 10th floor and provides a great view of Boston -- but it does much more.The building's glass shell has computer-controlled blinds and louvers, part of a system that keeps Genzyme's 900 employees warm in the winter and cool in the summer.

Genzyme Center is a state-of-the-art "green" building.

"We don't use electricity for any of the heating or cooling in the building," Bo Piela, director of public relations for Genzyme, said recently while conducting a tour of the building, which has become something of a shrine to a rapidly growing sector of environmentalists.

Genzyme even pipes in waste steam from a neighboring power-generating plant, to supplement both heating and cooling systems. The building has been open for 10 months, and it is projected to use a third less water than conventionally constructed buildings, and cut electricity costs to 40 percent of what they would be for a normal building of the same size.

With environmental awareness increasing, the price and difficulty of obtaining new energy rising, and the cost of making buildings energy-efficient dropping, the number of developers and communities embarking on green projects is exploding.

By one measure, Massachusetts ranks sixth among US states. It has 63 buildings that are registered with the US Green Building Council, a nonprofit coalition of building-industry representatives that promotes environmental development and certifies buildings if they meet strict standards.

While only a decade ago most people thought green was just a paint option, today the term signifies an industry coming into the mainstream. The numbers tell the story:

Products and services for so-called green buildings amounted to $5.8 billion in 2003, an increase of a third over the previous year.

Nationwide there are 126 building projects certified by the council as being green, up from 38 two years ago. As of this month, 1,636 project managers have taken at least the first step to apply for certification.

The Green Building Council's membership has grown by 10 times in the last four years, to almost 5,000.

And cities like Boston and Chicago are competing to become known as the "greenest" in the country.

Mayor Thomas M. Menino last year put together a task force to guide the city's development toward that title, starting with the private sector. "Chicago is a green-building leader," said Menino. "Our aim is to become a leader as well. If there's competition, that would be a contest that everyone would win."