AURORA, Colo. -- Rows of little plastic domes dot the roof of the new Wal-Mart Supercenter here, looking like a marching band of "Star Wars" R2-D2s.

Inside each dome, a trio of computer-aimed mirrors tracks the sun and bounces its light down a reflective shaft and through a milky white lens, illuminating the stockroom below.

The skylight idea is centuries old. But the mirrors, the lenses and dozens of other energy- and environment-saving innovations are new, and they're showing up not just at Wal-Mart but at other companies, schools and public agencies.

In addition to the Wal-Mart roof's legion of skylights, for example, the store's foundation is made of ground-up chunks of runway recycled from Denver's old Stapleton International Airport. Porous paving in its parking lot soaks up and filters polluted storm-water runoff.

Huge north-facing windows provide most of the store's interior light. Used motor oil from the tire and lube shop helps heat the store, as does old vegetable oil from the deli.

The new Wal-Mart off Parham Road in Henrico County, scheduled to open in January, is not a green store, said Richmond market manager Jeff Kraus. But it will have skylights to preserve energy.

According to Don Moseley, senior Wal-Mart engineer for environmental innovation, these and other efforts "are good for the environment and good for our business."

That's the mantra of the green-building movement that's sweeping the nation. Among the adherents are financial institutions such as Citigroup, PNC and Bank of America; automakers such as Toyota, General Motors, Ford and Honda; and such retailers as Target, Home Depot, Lowe's, Chipotle and Patagonia.

The next two new Major League Baseball parks, in Minneapolis and Washington, D.C., are poised to go green.

Future federal buildings will be green, too. The General Services Administration, the nation's biggest landlord, announced last spring that it was applying stringent green-building standards to its $12 billion construction portfolio of courthouses, post offices and border stations.

States are cracking down. Washington state began requiring in April 2005 that all state-funded construction projects larger than 5,000 square feet, including school-district buildings, be built green. Many other states -- including California, Arizona, Arkansas, Colorado, Connecticut, Florida, Michigan and Nevada have followed suit.

Virginia is not among them. "But it should be -- and it is strongly considering adopting green-building standards," said Karl Bren, a green-building consultant in Richmond.

The key to the movement are new standards that are far more demanding, environmentally speaking, than local building codes. The movement invites innovation because it's based on environment-protecting performance standards, not rules.

Standards for existing buildings and commercial interiors came out in 2004. Criteria for new single-family homes, public schools, hospitals and cookie-cutter commercial buildings such as bank and retail store branches will come in the next year or two.

The U.S. Green Building Council's goal is to "transform the marketplace" in real estate in the United States and globally, said Rick Fedrizzi, the council's founding chairman and chief executive officer. "We'll be at that point when it's no longer called green building; it's just the way building is done."

Council-certified green buildings have been spreading like wildfire since 2000. In that year, about $790 million in new commercial construction met the council's standards. This year, about $7.2 billion does.

The added costs of green building -- long assumed to be 10 percent to 20 percent more than traditional construction -- are falling and may have been exaggerated, according to some who've built green recently.