The annual Illuminating Engineering Society (IES) Street & Area Lighting Conference kicked off on September 19, and has an even stronger focus on LEDs than last year, with solid-state lighting (SSL) emerging as the clear choice for outdoor lighting. Meanwhile, Gurgaon, India, is planning an LED street-light project aiming to reduce maintenance efforts, and a Tallahassee shopping plaza has realized $100,000 in maintenance savings with an SSL conversion.
We will offer a more detailed account of SALC in the October issue of LEDs Magazine, but here are some tidbits from the event taking place this week in New Orleans, Louisiana. Nova Scotia, Canada is in the midst of a major LED-street-light project, and Jim McFadgen, engineering specialist at Nova Scotia Power, said, "Arguably the most disruptive technology advancement to ever hit the street-light industry is LEDs." Nova Scotia power has documented a 53% energy saving based on baseline SSL technology without adaptive controls or dimming.
Earlier this year, Tom Geist of the Electric Power Research Institute (EPRI) contributed an article to our publication on LED street-light field trials, and at SALC he presented some additional data. Geist said EPRI has documented energy savings in the range of 25-70% in different trial installations. But he added that there is other low-hanging fruit in terms of savings. He said that driver-efficiency improvements, temperature compensation in fixtures, and better quality control by fixture manufacturers could deliver more than 10% in additional savings.
SSL safe at lower light levels
Several speakers, including Ron Gibbons of the Virginia Tech Transportation Institute, addressed the growing belief that we can reduce lumen levels and maintain safe conditions for drivers and pedestrians when we deploy broad-spectrum white LED light. Gibbons said, "The physiology of the eye lends itself to broad-spectrum sources."
The audience ardently questioned Gibbons about the acceptance of white light, with several members insisting that it is more comfortable driving under yellow-to-orange high-pressure sodium (HPS) sources. Gibbons insisted that every study conducted finds that "people like white light better," although they may not realize it until going through a controlled experiment.
The debate about the most-efficient light source continues, although the experts at SALC agreed that LEDs will surpass all legacy sources including HPS – a source that many say today is generally more efficient than LEDs. The point is that LED efficiency is still ramping steeply while HPS and other legacy sources are improving very slowly.
Mark McClear, Global Director of Applications Engineering at Cree, noted that LED luminaire efficacy has improved from 50 to 90 lm/W, at maximum drive current, over the last six years. McClear projects that system efficacy for sources in the 4100K CCT range will hit 120 lm/W within the next 2-3 years. McClear said, "LEDs will be the most efficient light source available."
There will be a lot of other good material in our October feature. SALC had a lot of content related to controls, a technology that can multiply energy and maintenance savings. Moreover, the SALC program included good details on some of the latest SSL trials. Stay tuned.
SSL in Tallahassee, FL
Meanwhile, here are some of the latest announcements of SSL outdoor installations. In Tallahassee, Florida, the owners of the Market Square shopping plaza have replaced 1000W metal halide (MH) lights with 300W LEDs, according to the Tallahassee Democrat. Energy consultant kWControl assisted in the retrofit and projects an annual saving of $100,000 just in maintenance costs. The upgrade used EvoLucia luminaires.
According to The Times of India, the city of Gurgaon, India plans to install LED street lights with remote monitoring and adaptive controls. A major problem with the existing street lights is detecting failures and the city intends to eliminate that issue via networked lighting.
Ilion, New York installed around 100 LED street lights two years ago, and having achieved favorable results hopes to embark on other projects, according to The Observer Dispatch. The city has achieved approximately 50% energy savings. The city hopes to tap funding from the New York State Energy Research and Development Authority.