Using LEDs for general lighting may finally be a bright idea.
In the past few years, light-emitting diodes have made huge advances in energy efficiency. Industry sources and outside experts say LEDs are now the most energy-efficient lighting source available. They use far less energy than other bulbs, last a lot longer, and cost less to use over their lifetime.
For now, the lights still cost more than the average consumer is used to spending on a light bulb -- a lot more. Prices for LEDs on the market today can be more than five times what an incandescent bulb costs.
However, the LEDs use about 85% less energy and last 30 times longer. They also use about half as much energy and last five times longer than compact fluorescent lights.
"incandescent" - 熾熱的,白熱的。 "fluorescent" - 螢光的。
Manufacturers' game plan is to first target commercial and industrial customers, for whom the economics of LEDs are increasingly too compelling to ignore. Such customers leave their lights on most or all of the time and pay labor costs each time bulbs are changed. Longer-lasting lights that use less energy thus offer them significant savings over time.
Then, as sales increase, creating economies of scale and bringing down production costs and prices, the industry will expand its marketing to residential customers in a push that many observers expect will make LEDs the lighting of choice for years to come.
Jim Brodrick, Solid State Lighting program manager for the U.S. Department of Energy, predicts that LEDs will save Americans $280 billion in energy costs over the next 20 years, and that the technology will make up 70% of the market by the end of that period.
Beyond CFLs
Philips Lighting, part of Netherlands-based Royal Philips Electronics, sees LEDs as the future. It has spent $4.2 billion in LED company acquisitions over the past two years. Philips has been one of the largest manufacturers of compact fluorescent lights, or CFLs, another energy-efficient alternative to incandescent lighting.
But CFLs contain mercury, an environmental hazard. The company has virtually halted research on such lights, shifting its development spending to LEDs instead.
"People are desperate for something beyond CFLs," says Kevin Dowling, vice president of innovation at Philips Solid State Lighting Solutions. "LEDs are getting more efficient by the month. Traditional lighting technology has leveled off."
Strategies Unlimited, a market-research firm specializing in advanced electronics, forecasts that sales of LEDs, which accounted for a minuscule $330 million of the $15 billion lighting market in 2007, will grow 40% this year and reach $1.6 billion by 2012. "It's a small base" but "it's growing fast," says Robert Steele, a principal at the Mountain View, Calif., firm.
LEDs consist of a small semiconductor that emits photons when electricity is applied. For decades, they've been used as indicator lights for small applications like remote controls and stereos. A major hurdle to their broader use for industrial and residential lighting, however, was manufacturers' inability to boost brightness without increasing power consumption too much.
Brighter, Stronger
Now that challenge has been largely solved. Advances in materials used in LEDs have led to an explosion in technological improvements at the leading LED companies over the past two years. An LED light and fixture on the market from Cree Inc., a Durham N.C.-based LED maker, produces about 60 lumens per watt, a measure of lighting efficiency. That product is about as bright as a 65-watt incandescent bulb, while using only about one-sixth of the power. The LED lamp also has an estimated life of about 50,000 hours, about 33 times longer than that of an incandescent light.
Some companies and a growing number of cities have started adding LEDs incrementally. For such users, the savings LEDs provide on energy bills, bulb-replacement and labor costs can often cover the higher up-front cost in about a year, industry experts say.
Raleigh, N.C., recently installed LED lights in parking decks and other outdoor spaces. Dan Howe, assistant city manager, estimates that in one underground parking deck the change will save the city more than $700,000 in energy and maintenance costs over the 15-year lifetime of the LED products.
"In four or five years, it will be a no-brainer," Mr. Howe says. "Nobody is going to be doing anything without LEDs." Residents have responded favorably as well, says Mr. Howe, who adds that the city plans to retrofit more city lighting with LEDs. "We're about to spend $500,000 retrofitting perfectly good decks with perfectly good lighting in them because we're saying the paybacks are coming much faster," he says.
Wal-Mart Stores Inc., after tests at two of its stores in Texas and Colorado, has decided to use LEDs in the freezers and refrigerators at all 4,200 of its stores in the U.S. A company spokesperson adds that tests are under way of LED lights in the parking lot of a Wal-Mart store in Arkansas.
Sticker Shock
For now, price remains the biggest obstacle, especially for residential use. But there are signs that this is changing as well. Consider "down lights," the kind of directional, recessed lighting that is common in many homes and offices. LEDs are well-suited for this kind of lighting because they typically provide directional light (although some LED lamps have added lenses to give more diffuse light). But despite their suitability for this purpose, Sloan Ritchie, a sustainable-home builder in Seattle, says he isn't yet installing LED down lights because they're too expensive: about $80 each, compared with $15 for an incandescent and $35 for a fluorescent. Even though LEDs offer savings in the long run -- and use less energy -- consumers still are reluctant to pay more up front. However, with LED prices falling about 25% a year, Mr. Ritchie says he may begin using them next year.
Some manufacturers already are test-marketing products in stores of Home Depot Inc., the big home-improvement retailer.
"Within one to two years we will see much broader retail availability," says Michael Siminovitch, a University of California at Davis professor and head of the California Lighting Technology Center, a research organization based in Davis, Calif.
The flexibility that LEDs give designers and architects to be more creative will change the way people look at lighting, Mr. Siminovitch says. "They are very controllable," he says. "You could start putting light in different places; maybe surfaces start glowing, or the walls light up, or the floors light up."
Remaining Challenges
Several things still have to happen, meanwhile, for the LED market itself to light up. For one, as often happens with new technology, the quality of LED products currently on the market is uneven. Of 140 LED products in stores and tested by the U.S. Energy Department, more than half were considered poor quality. People get kind of interested, says the Energy Department's Mr. Brodrick, "but buying it is something else."
To address quality concerns, the American National Standards Institute released the first LED standard early this year. More recently, the Illuminating Engineering Society of North America, the standard-setting body for the lighting industry, created two more standards. The Energy Department and the Environmental Protection Agency, meanwhile, also have released an LED Energy Star standard like the one for appliances.
Manufacturers can begin using the LED Energy Star label this month. Companies whose products fail to meet the specifications can either try to improve their products or remove them from the market. Product test results are posted on an Energy Department Web site (www.netl.doe.gov/ssl/comm_testing.htm).
Another challenge is a shortage of LED-friendly light fixtures. LEDs work best in fixtures that are designed for them, using special materials that remove excess heat. The heat produced by the LEDs needs to be removed, otherwise it will damage the chip, reducing its lifespan. Standard light fixtures can do a poor job removing that heat. But companies that make fixtures have only recently begun designing products specifically for use with LEDs, so availability is limited.
Leading LED manufacturers have responded by buying their own fixture makers. Earlier this year, Cree purchased LED Lighting Fixtures Inc., and Lighting Science Group Corp., a New York-based LED product company, purchased Netherlands-based Lighting Partner BV.
