LED Streetlight Application Assessment Project Pilot Study in Seattle, WA

Abstract

Recent studies have found that light emitting diode (LED) technology is becoming competitive for streetlight applications with the commonly employed high intensity discharge (HID) light sources such as high pressure sodium (HPS) and metal halide (MH). The expectation is that LED street lighting technology will not only provide more efficient light distribution and increased uniformity, but will also save energy and reduce maintenance costs. Seattle City Light (SCL) has a street lighting system of nearly 84,000 street and area lights that use predominantly HPS light sources. Because of the potential benefits of installing LED luminaires as a replacement for these lights, SCL launched the LED Streetlight Application Assessment Project Pilot Study to evaluate LED luminaires for photometric performance, energy efficiency, economic performance, and the impact of the new lights on SCL streetlight system. Project findings will be used by SCL to develop a strategy for the installation of LED streetlights in developing an energy efficient lighting system. The major elements of this project included LED luminaire selection, simulated photometric performance of selected LED products using AGI32, field photometric performance evaluation at selected test sites, and economic performance evaluation in comparison to HPS luminaires. In addition, since combining LED roadway luminaires with new light control systems provides many new options for overall light control, facilitating maintenance, increasing luminaire life, and further reducing operating costs, a preliminary review of current cutting-edge lighting control systems were explored.