[Exclusive] US DOE Releases LED Outdoor Lighting Report, Performance Significantly Improved

The U.S. Department of Energy (DOE) reported last August that outdoor LED lighting could not yet reach the level of 400W high-pressure sodium (HPS) lamps. Nearly a year later, the U.S. Department of Energy has recently released a Caliper report on the actual application of outdoor LED area lighting products, stating that solid-state lighting (SSL) manufacturers can now deliver such products. In addition, efficacy continues to improve and lighting quality has also been enhanced (the report can be downloaded as an attachment).

The report states that a major trend today is the shift from last year's mainstream 6500K LED lighting toward a slightly warmer color temperature of 4000K, with high-end products reaching an efficacy of 150 lumens per watt. The U.S. Department of Energy stated that, in the surveyed outdoor area lighting product database, street lights account for 23%, with the remaining 7% being parking lot, canopy, and directional luminaires. It was also noted that 16 products in the database exceeded 120 lumens per watt, of which seven products had a CRI above 80, and only one had a color rendering index below 70. Such lighting provides color rendering far superior to high-pressure sodium lamps, making it easier for pedestrians to drive and identify objects.

Although the lumen output of 400W HPS-equivalent LED products is still at the lower end of the lumen output range of HPS luminaires, LED products offer superior efficacy. In addition, studies have shown that LED lighting, at lower lumen outputs with a broader spectrum, provides better visibility. In fact, in field tests of LED street lights in Seattle, it was found that LED lights installed two years ago, even though they had become relatively dim, showed only a slight decline in object recognition capability.

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