The green underwear produced at a new lingerie factory in Thulhiriya, Sri Lanka — perhaps the world’s first carbon-neutral clothes factory — hits the streets of the U.K. this month and will cost no more than existing garments, TheEconomist reports.

For Britain’s largest clothier, Marks & Spencer, the factory is part of its five-year drive to become carbon-neutral by 2012. MAS, contributed $400,000 toward the cost of the factory’s deisgn and solar panels, which provide 10 percent of its energy needs. MAS expects the factory’s 25-percent higher construction costs — about $7 million — to have paid for themselves in less than five years.

“The MAS factory is a truly exciting development in clothing production,” Sir Stuart Rose, chief executive of M&S said at the opening. “It really has been a partnership of two like-minded companies, M&S and MAS, and will trial a completely new approach to manufacturing and set standards for others to follow. Not only has it been designed to be carbon neutral, use less electricity and less water than a similar scale clothing factory, it will also produce great quality lingerie products – what our customers would expect from M&S – whilst ensuring its workers are treated well through its leading standards in employee welfare.”

The MAS Holdings factory, Sri Lanka’s largest apparel manufacturer, uses evaporative cooling instead of air conditioning; is powered 100 percent by renewable energy (90percent hydroelectric); has enough natural light for workers; and uses 40 percent less energy than most factories its size.

MAS says it has reduced carbon-dioxide emissions from its British operations by nine percent, despite opening 103 new stores, and plans to reduce its emissions more with a fleet of 140 tear-shaped trailers, which use 10 percent less fuel and provide 16 percent more space than their less aerodynamic forebears do.

MAS announced the construction on its 110,000-square-foot eco-friendly plant in November, 2007.