The U.S. Department of Energy has published the final report of a demonstration project of LED roadway lighting conducted at three sites in Philadelphia. The report provides a performance evaluation of 10 different LED luminaires—and compares them to the incumbent high-pressure sodium (HPS) luminaires—using manufacturer data, illuminance calculations, field measurements, and subjective observations.
The findings include that all of the LED luminaires had higher application efficacies than their HPS counterparts; that is, they delivered more lumens to the target areas (roadway and sidewalks) per watt of input power. They also drew between 10% and 40% less power, and generally provided more uniform illumination.
Although energy savings alone are unlikely to result in a reasonable payback period, additional savings from reduced maintenance requirements could make widespread luminaire replacement cost-effective.
-tk-