The conclusions of a recent report by the National Lighting Product Information Program (NLPIP) were not aligned with the aim of the study, according to Department of Energy (DOE) officials.
While the study was framed as a product comparison, conclusions focused more on poor fixture selection and the ability of individuals selecting fixtures to make the right decisions, according to Marc Ledbetter, program manager of the emerging technologies program at Pacific Northwest National Laboratories, a U.S. Department of Energy laboratory.
The NLPIP, a program managed by the Lighting Research Center at Rensselaer Polytechnic Institute, compared performance of manufacturer-supplied LED, induction, and high pressure sodium (HPS) streetlights on a one mile section of a collector road. The NLPIP concluded that based on the LED fixtures supplied, illumination levels did not meet minimum specifications, and therefore narrower pole spacings were necessary. This, in turn, would make LED streetlights cost prohibitive in comparison with HPS or pulse-start metal halide streetlights. Solid state lighting manufacturers and representatives of government agencies quickly responded to the report, which resulted in NLPIP publishing an addendum with clarifications and responses to industry comments.
“Our primary concern was with the methodology and technical approach of the NLPIP report,” said Ledbetter. He and other government officials indicated that if the correct fixtures had been selected, the results of the study would have been significantly different.
In the addendum to the initial report, the NLPIP reported findings gathered from an additional installation of LED streetlights, which matched the pole spacing of the collector road. These additional tests concluded that LED streetlights did provide modest energy savings but still had a higher life cycle cost than the existing HPS fixtures.
However, according to Russ Leslie, associate director of the Lighting Research Center, “The key to a product comparison is making sure that you are getting the same light levels and same performance when evaluating fixtures. If the same tests and procedures were done today, the results would probably be different. The likelihood of LEDs improving is very high and so are resulting future price drops.”
The implications of the NLPIP report and the response from DOE and the industry for municipalities are simple, according to lighting experts. Municipalities considering new lights involving any new technology must conduct due diligence and consider each specific application of streetlights. The technology must be suitable for the application in question, and field tests of fixtures can provide valuable insight into real world performance of LED and other energy efficient lighting. Reviewing the test findings and product selections of cities which have now established successful track records of deploying LED streetlights, like Los Angeles, California, can help municipalities entering the world of energy efficient lighting.