Below is my contribution to the September 2018 issue of tED Magazine, published by the National Association of Electrical Distributors. Reprinted with permission.
The major technological shift to the LED light source has had a major impact on the outdoor stationary lighting market. In its latest solid-state lighting energy savings forecast, the U.S. Department of Energy (DOE) continued to recognize area and roadway lighting market as leading in LED adoption. In this market, DOE estimated 21 percent LED penetration in the installed base in 2015, projecting 91 percent by 2025.
LED’s expanding capabilities are well suited to evolving needs in outdoor lighting, while highly competitive efficacies and declining costs make it steadily more attractive for upgrades. This article identifies key trends in LED outdoor lighting is used as well as technology and design trends impacting the development of LED lighting and controls.
Efficiency and reliability
The efficacy (lumens/W) of LED luminaires has surpassed that of even high-pressure sodium lamps, with the most efficacious outdoor LED luminaires most readily identifiable under the DesignLights Consortium’s Premium designation in its Qualified Products List. Coupled with much longer life, long average mean time between failures, ruggedness, compact size, and controllability, LED offers a compelling alternative to traditional technologies. Over the past several years, outdoor LED lighting has seen advances in lumen maintenance, color consistency, and light output per LED (which in turn is driving development of smaller, sleeker form factors).
As the technology matures, however, maximum efficacy appears to be beginning to plateau. “When the technology was new, efficiency gains were significant as advances were made, but now that it’s reaching maturity, those gains have slowed significantly,” said Teresa Bair, Product General Manager – Outdoor and Industrial Lighting, Current by GE.
As a result, she added, manufacturers are focusing on new points of differentiation and value, from sleeker form factors to controllability to lighter housing materials. Another area of focus is reliability.
“Competitors are able to replicate efficiency and lumens per watt more easily, but customers quickly realize efficiency does not always translate to reliability, so there is an increasing focus on reliability,” Bair said. “Specifically, driver reliability is becoming an increasingly popular topic.”
Performance and aesthetics
“Energy efficiency, lumen maintenance, and optical distributions continue to differentiate luminaires on a performance basis,” said Amy-Christina Giacobello, Product Marketing Manager, Lumark, Eaton Lighting. “Good quality differentiators tend to be more in the details of the product qualifications, such as IP rating, vibration ratings, ambient temperature ratings, et cetera.”
Otherwise, quality lighting is becoming more important. “Quality lighting that is placed correctly can help establish feelings of safety and security,” Giacobello went on. “In communities, pedestrians may assume drivers can see them after dark, but if overhead lighting is insufficient, they may be in danger. Pedestrian-scale lighting is lower and spaced more closely together than regular roadway lighting. Using LEDs can further increase safety and security by improving light spread and eliminating dark spots.”
She added that the pedestrian experience is also key to commercial activity. As a result, municipalities are looking for architectural lighting solutions that entice pedestrian traffic. “Generally, cities couldn’t afford to focus on these things in the past, but LED technology makes them much more affordable,” Giacobello said.
Jeff McClow, Senior Product Manager, Hubbell Lighting, said LED technology has changed outdoor lighting in improved light source control, both in the optical and electrical sense. “One important product trend is efficient diffuse and edge-lit solutions that deliver reasonable lighting distributions beyond basic symmetric and slight forward asymmetric shapes,” he said, pointing out that due to energy code changes and design improvements, outdoor LED luminaires continue to undergo rapid product change.
McClow added that customers are looking for cost reductions by leveraging optical distribution to reduce the number of poles required. “The total costs on a project can be driven down by using fewer fixtures with lower wattages,” he said. “This is accomplished by using fixtures with the best photometric performance within the established budget.”
Another performance trend is lower correlated color temperatures (CCTs), driven by the American Medical Association’s (AMA) 2016 community lighting guidelines. Despite some pushback from the lighting industry, the guidelines, which specifically recommend 3000K sources as having a lower potential impact on circadian health, have had a significant impact on customer preference. At one time, this would have required sacrificing energy efficiency, but the efficacy gap between cool- and warm-CCT sources has been diminishing in recent years.
“Aesthetically,” said Bair, “many clients prefer lower CCTs because it more closely replicates what people have grown accustomed to with older metal halide or high-pressure sodium lights. People feel it is more welcoming and aesthetically pleasing, especially in applications such as a residential neighborhood or a park.”
Control and connectivity
Commercial building energy codes are demanding in terms of control of outdoor lighting, requiring automatic shutoff and light reduction based on time of day or occupancy. As lighting control requirements became widespread and more complex, the industry responded with a standardized NEMA twist-lock ANSI C136.41 control receptacle, now a common feature in outdoor luminaires. This receptacle enables connection to 0-10V or DALI dimming controls as well as sensors and communication devices, providing a control-ready product now and/or for the future.
“Standards create traction in the market as customers have greater confidence in the solution,” said Jay Sachetti, Sr., Marketing Manager, Connected Communities, Eaton Lighting. “The receptacle allows customers to retrofit existing luminaires to LED today with the ability to come back at a later date to update or add connected controls as technology continues to evolve, and know that certain functionalities are already built into the system. Ultimately, these receptacles can provide a connection point and power source for other smart city devices as standards continue to evolve and mature.”
Specifically, these control devices may use wireless communication as a means of connecting the luminaires into a system. Wireless controls have found excellent utility in outdoor lighting, providing remote control and communication without dedicated wiring. This enables programming, measurement, and monitoring of an outdoor lighting system’s performance. “This type of connected network provides unprecedented ability to control a vast network of outdoor lights from one location,” Bair said. “Users can view real-time diagnostics so instead of a streetlight that has burnt out going unnoticed and causing resident complaints, user of the system will have real-time visibility to the performance of all lights within their network. Users can also create various reports to verify actual energy consumption and other parameters of each light fixture, enabling analysis and forecasting for future electricity usage and maintenance requirements.”
She added that the combination of connectivity, bandwidth, data storage, and software provides a platform for implementing Internet of Things (IoT) strategies. By adding third-party software, data collected by the lighting system can be repurposed. By adding sensors, additional capabilities can be incorporated into the system. This allows capabilities such as asset management, gunshot detection, traffic monitoring, and more.
“Distributors should be thinking beyond just the LED lighting fixture,” Bair said. “Start becoming familiar with these emerging sensors and controls, because in the very near future, it will become increasingly rare that a buyer would buy just the fixture. The projects of tomorrow are going to feature these wireless outdoor lighting systems, which means LED fixtures with electronic nodes, sensors, and software. This can open up new revenue streams for distributors willing to expand beyond just fixtures and bulbs.”