LEDs Emerge to Fight Fluorescents

Nippo's Linear T6 Fluorescent System illuminates attendees at the Lightfair International trade show Tuesday, May 8, 2007 in New York. The light bulb, the symbol of bright ideas, doesn't look like such a great idea anymore, as lawmakers in the U.S. and abroad are talking about banning the century-old technology because of its contribution to global warming. But what comes next? Compact fluorescent bulbs are the only real alternative right now, but "bulbs" that use light-emitting diodes, or LEDs, are quickly emerging as a challenger. (AP Photo/Mark Lennihan) (Mark Lennihan - AP)

Dallas-based Lighting Science Group Corp. showed an LED "bulb" that screws into a standard medium-sized socket and produces a warm light equivalent to that of a 25-watt incandescent bulb, but consumes just 5.8 watts. It costs $50, hardly palatable to consumers who can buy a standard bulb for less than a dollar.

Polybrite International, a startup in Naperville, Ill., announced that lighting giant Osram Sylvania, a subsidiary of Germany's Siemens AG, will distribute its LED "bulbs." The intended market is mainly commercial clients, who can afford to pay $15 to $85 per unit, according to Osram Sylvania marketing manager Constance Pineault.

The energy efficiency is no doubt a draw for commercial clients like hotels, but LEDs have another big advantage: they last up to 50,000 hours, according to manufacturers. That compares to about 10,000 hours for fluorescents and 1,000 hours for incandescents. Not having to send out janitors to replace burned-out bulbs means big savings in maintenance costs.

"Right now the applications that make sense are either high maintenance or high power consumption, like parking garages, where the lights are on all the time," said Cree's Merritt.

LEDs already beat fluorescents for energy efficiency in some niche uses. For instance, Wal-Mart Stores Inc. is putting LED lighting in its in-store refrigerators, where the cold dims fluorescents and incandescents produce too much heat. LEDs also starting to replace flat fluorescent backlights in liquid-crystal displays, or LCDs, where they produce better colors.

LEDs don't contain toxic mercury, which CFLs do, though the amount is very small. (Recent stories circulating on the Web about calling a hazmat team if a CFL breaks are exaggerated. The U.S. Environmental Protection Agency recommends sweeping up, not vacuuming, the fragments, then checking out local recycling options.)

The cost of LED lighting should be coming down quickly. Polybrite founder Carl Scianna said the cost of individual white-light diodes, several of which go into an LED bulb and make up much of the cost, have come down in price from about $8 to $1.50 in a year.

"They're going to keep going down," Scianna said. "By the middle of next year, they'll be priced for consumers."

Nadarajah Narendran, director of lighting research at Rensselaer Polytechnic Institute in Troy, N.Y., cautions that there are still technical issues to work out with LEDs.

While single LEDs can demonstrate very high energy efficiency in the lab, when they're combined into fixtures, their efficiency is considerably lower. In part that's a heat issue: the diodes produce less heat than incandescents, but they keep that heat in the fixture rather than radiating it, and the hotter the diodes get, the less efficient they are.

He sees screwing LED bulbs into standard sockets "as a waste of talent" that doesn't utilize the inherent properties of LEDs, like their small size and longevity.

"You could build them in as part of the furniture, part of the cabinetry," Narendran said.

Because of their high prices, he doesn't believe LEDs will be ready to replace incandescents in all their uses for the next five to 10 years, but "LEDs, good or bad, will be growing very rapidly."

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On the Net:

U.S. Department of Energy on LEDs: http://www.netl.doe.gov/ssl/

Recycling options for CFLs: http://www.lamprecycle.org

http://www.cree.com

Lighting Science Group: http://www.lsgc.com/