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  • LEDs light the way to energy savings

Photonics Spectra
Dec 2008
Caren B. Les,

WASHINGTON – LEDs in niche lighting markets now save consumers nearly $1 billion in electricity costs – and if switched over entirely to LEDs, consumers collectively could save more than $20 billion, according to analyses conducted by the US Department of Energy (DoE).

In September of this year, the department released a 98-page report titled “Energy Savings Estimates of Light Emitting Diodes in Niche Lighting Applications,” in which the advantages of LEDs over traditional lighting sources in certain applications were examined. The lineup of traditional sources includes incandescent, halogen, fluorescent, neon and high-intensity discharge lights.


LEDs light the way in a pilot project in Raleigh, NC. Photo courtesy of BetaLED.

The analysis indicated that LEDs are currently most widely used in colored-light applications, including traffic signals and pedestrian crossings, exit signs, electric signage and holiday decorations. They produce light in the desired emission color, which requires less energy, while incandescent or compact fluorescent sources produce full-color-spectrum light and require a filter to produce a specific color.

White-light LED applications found to have the greatest future energy savings potential include recessed downlighting; street- and area lighting; outdoor step, path and porch lighting; task lighting; retail displays; and refrigerated display cases.

More widespread use of LED-based recessed downlights for ambient lighting in homes and offices could provide significant energy savings, according to the report. If all recessed downlights in the US were converted to LEDs, it is estimated that the energy savings would be equivalent to the annual electricity consumption of 6.7 million US households.

LEDs have only recently become available for these applications and had not gained a significant share of the markets as of 2007. Research currently is being conducted in white-light technology, and the advancements in areas such as efficacy, lumen output and operating life are anticipated.

Lighting designers are taking advantage of LED features, including their durability and ability to directly illuminate a specific product in a display case. LED lighting can be dimmed or brightened, and well-designed products can reduce glare and provide more uniform illumination.

Exit here

Required in public buildings, the ubiquitous and reassuring lighted exit signs are predominantly LED-based because the technology consumes less energy and involves lower maintenance costs than other sources. More than 85 percent of exit signs incorporated LEDs in 2007. This niche market represents 52 percent of the total energy savings attributable to LEDs in 2007, the report states.

It also is estimated that, if all exit signs were converted to LEDs, the energy savings would amount to the equivalent of the annual electricity consumption of more than 300,000 households. The government’s Energy Star program requires that exit signs installed after Jan. 1, 2006, consume no more than 5 W per face, which is achieved cost-effectively with LEDs.


Traffic signal heads were the second highest energy-savings niche market for LEDs in 2007, representing approximately 32 percent of the total energy savings.

LED-based traffic signals and pedestrian crossings meet Energy Star requirements, while their long operating life reduces maintenance costs and enhances safety. About half of all traffic signals already use LEDs, according to the report. If the remaining incandescent traffic signals were converted to LEDs, it is estimated that the amount of electricity conserved would be equivalent to the annual electricity consumption of 400,000 typical US households.

Your name in lights

If the nation’s inventory of neon electric signage were to shift entirely to LED technology, the energy savings would equal the annual electricity consumption of 600,000 households. LEDs have gained a 6.1 percent share of the electric signage market in 2007, up from a negligible amount in 2002, according to the report. The estimate is based on LED replacement of electrically lit neon signage, including shaped neon-tube channel letter signs, reverse channel letters and border lighting.

A seasonal glow

As for holiday lights, the report notes that, if we were to convert the twinkling lights on our hundreds of millions of trees and festively decorated halls from incandescent to LED sources, we could conserve energy savings that would be the equivalent to the annual electricity consumption of almost 500,000 households, or the output of 90 percent of one large (1000 MW) electric power plant.

LED holiday lights have operating lifetimes 30 times longer than those of traditional miniature lights and 90 percent lower energy consumption per lamp, according to the report. Thus far, LEDs now represent a 5.2 percent share in the holiday lighting market. Because of their capacity to produce a spectrum of colored light, depending on the chip substrate, they are particularly suited to this application and may replace traditional lighting over time.

Cool cases

LEDs are showing promise in the refrigerated display case lighting systems market, having gained a 3.6 percent market share in 2007. The report states that technical advances in white LEDs offer energy savings when replacing fluorescent systems. Although less than 1 percent of the market has switched to LED systems, it is estimated that if the entire market were to switch to LEDs, the savings would be equivalent to the annual electricity consumption of more than 160,000 households.

Compared with the traditional fluorescent refrigerated display case lighting, LED systems operate more efficiently at colder temperatures, and their light can be directed toward the displayed products. LEDs also are more suitable for meat display applications because they provide a similar level of illumination while radiating less heat, thus decreasing the growth of bacteria and increasing the shelf life of the meat.

Dr. James R. Brodrick, program manager for lighting research and development at the DoE, said that, although the study concentrates on markets that are having an immediate impact on energy savings, the department is focusing its long-term efforts on very large energy savings potential. He added that the DoE has been expecting a huge shift from colored lights to white light and has been emphasizing research in the latter area for years.

He noted that, according to departmental projections, research in a variety of areas may raise the efficacy of LEDs to 230 lm/W, up from the current rate of 20 to 88 lm/W. We also can expect to see many new products and for quality to continue to vary widely, he added. To check for quality, consumers should begin to look for the first LED luminaires that qualify for the Energy Star, he said.

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