By Michael F. Carmichael
Nov. 3, 2011
Not only are your streetlights going green by way of LEDs (Light Emitting Diodes), but they’re getting smarter than most of us. They’re dimming when their “normal” light isn’t needed - like residential areas after the 11 p.m. news - and they can show first responders to the house that called 911 among a whole host of other talents.
Crawford Lipsey is CEO of Relume Technologies, the company leading the way for municipalities to go green while saving their taxpayers significant money. He says that the company name is pronounced “ree-lume” - as in “re-luminate.” Therein lies just one of the ways municipalities across the country are switching to talented and money-saving LED streetlights. The new lights can use the existing poles and wiring, saving on installation.
But, why are LED streetlights just now becoming popular? “It was really a breakthrough in technology,” explains Lipsey. “The company started back in 1999 and stayed small for a very long time. Peter Hochstein, the founder who passed away this past May, was with the ‘Black Ops Group’ at General Motors Corp. He was a pioneer in what’s called thermal management.
One of Hochstein’s projects involved a way in which the vehicles in a military convoy could communicate “from taillight to headlight,” Lipsey says. “Because convoys were moving a lot at night, under radio silence - they certainly didn’t want lights on, so they had infrared lighting via LED lights that provided communications from the lead vehicle to those behind. A lot of the time convoys traveling at night in the desert would get lost. If the convoy is a mile or two in length and one guy takes a wrong turn-¦ . So the infrared LEDs would allow them to communicate safely.”
“LEDs [for commercial use] didn’t really become popular because the light wasn’t that good,” Lipsey continues. “It produced very low lumens per watt and just wasn’t that efficient. The enemy of LEDs is heat.” Hochstein effectively solved both issues - the volume of light LEDs could produce as well as how to dissipate the heat.
With those problems solved, cities across the country are turning to Relume and other manufacturers - primarily because they can save precious budget dollars. “We’re saving upward of 60 percent on their energy costs for an installation in Ann Arbor, Mich.,” says Lipsey proudly. “Depending on the cost per kilowatt hour, the payback can be as little as three years. So energy savings is first and foremost.”
“Second,” he continues, “is maintenance. Our fixtures can last anywhere between 70,000 and 100,000 hours. That’s considerable compared with the traditional streetlight, which has a life of between 15,000 and 24,000 hours. It’s expensive to go out with bucket trucks and shut down streets to re-lamp the fixtures so maintenance is the second largest driver to go with LEDs.”
Lipsey says that yet another advantage of LEDs is their ability to provide a variety of light “looks” that results from the color temperature of the LEDs themselves as measured in degrees Kelvin. Unlike compact fluorescent lights that are making their way into commercial and residential use - and which were initially panned because of their “colder” blue-white light - LEDs can be almost any color of white from warm (actually fewer degrees Kelvin) to a light closer to daylight (which is in the higher Kelvin range.) “Things appear to be brighter, with less light,” with LEDs, says Lipsey.
Control Features Are Key
The fourth benefit to municipalities who choose LED streetlights is that they can be controlled. “They can be dimmed very easily,” says Lipsey. “When you dim LED lighting 20 percent you get a 20 percent reduction in power. When you dim traditional lighting 20 percent you only get 50-60 percent of the power savings.” There is also an extensive range of dimming capability for LED streetlights, depending on the needs of the city. “They can be dimmed from 100 percent down to 10 percent,” Lipsey explains, “and the color temperature stays constant. One of the best things is that you can dim them down to about 50 percent and it’s not noticeable at all. Your eye can’t tell the difference. When businesses are shut down - say from 10 p.m. to 6:30 a.m. - you could go to 40 or 50 percent and have no visual impact.” All the while saving even more on the city’s electric bill.
“The lighting industry now is really a technology market with the development of LEDs,” says Lipsey. “It’s opened the doors for many companies like us to come in and do our quick-to-market technology solutions.”
Lipsey explains that “LED is only the fourth lighting technology ever invented after Edison invented the incandescent bulb. It’s pretty amazing.”
Well-lighted sidewalks and streets are a good thing. Spilling that light into the heavens not only wastes electricity but it pollutes the night sky. An organization called the International Dark-Sky Association has awarded Relume with its “fixture seal of approval” for their ability to keep light where it belongs and not trespass on the sky. “LED, as opposed to a fluorescent light source, is a point source - which means that you can control each LED in a fixture,” Lipsey explains. “We’ve developed optical systems for them that focus their light on a 90-degree horizontal plane - so they illuminate the sidewalk or street and not escape into the sky.”
As LED fixtures continue to be accepted by cities and other municipalities, they’re also expanding into other areas. Lipsey says that they’ve been very successful in creating well-lit parking garages. “There’s virtually no glare with extremely uniform lighting which is important in a parking garage.” Think of the last time you were in one where there were blindingly-bright overhead fixtures and then a pedestrian steps out of a darkened stairway on the way to their car - and you see them just in time.
Lipsey says that another feature of Relume’s LED streetlights, as well as their commercial parking garage lighting system, is the control capability called Sentinel. “It allows the LED fixtures to be dimmed wirelessly. We’re just finishing up one of the largest projects in the country, in Arlington, Va.
Save The Dark Sky
Shahid Abbas is manager of Arlington City and County Street Standards. Abbas says that Arlington decided two years ago to embrace the changeover to LEDs wholeheartedly, “from traffic lights to streetlights. Other places are still doing tests and trials and we said the time for those is over. Our goal is to save close to 70 percent in electric charges - and, at the same time, because we are a very green community we wanted to reduce pollution - including light pollution.”
In addition to saving money and eliminating light pollution, Abbas said they asked citizens what they thought about the way the light fixtures looked. “For all the good features they provide it can happen that the people just don’t like the lights, you know?” he laughs. They liked the Relume models.
“We’re a very populous area so we wanted to have both adequate lighting and the ability to control it when we didn’t need it as bright. We have different programs for commercial areas as well as residential. We can save as much as 80 percent of our electrical charges [by dimming when appropriate] and keep residents happy because we don’t have bright lights shining in their windows all night.”
Abbas explains that an inspection committee from the International Dark Sky Association visited Arlington and was impressed that the county met or exceeded their international standards. “Soon after the visit,” Shahid laughs, “I started getting calls from all over the world asking me about our lighting program - from Abu Dhabi, even!”
Perhaps it was because Arlington has a number of Washington bureaucrats living within its borders, but Abbas said that the only hitch he had in implementing the wireless control feature of his LED streetlights was getting approval from the Federal Communications Commission to use a specific part of the broadcast spectrum. “It happened in record time, the FCC told me,” Abbas explains. “One of the things we can do, if Washington ever needs to be evacuated for any reason, is show the traffic the way to go by sequentially flashing the streetlights. And, Arlington is the major evacuation route for DC.” The result would be similar to the evacuation lights in the cabin floor of many airplanes that guide you to the correct exit. “You could have major routes flashing in one fashion, and minor routes flashing in a different fashion.”
An additional feature that relates to the safety of his citizens, Abbas explains, is the ability to link the streetlights to the 911 system. “If there’s an emergency and we have streetlights nearby, they start flashing and the public safety people don’t have to look for the address. It’s a pilot program and that’s another reason the FCC acted so quickly.”
The Relume streetlights in Arlington were kits that were used to replace their existing streetlights.
“Retrofit is a large part of our municipal business,” says Lipsey. “It’s an expertise that we have. It’s more than sticking LEDs in a fixture. We have what are called ‘light engines’ to which we add optical design so that the light goes where it’s designed to and isn’t just a blob. It also allows for wireless controls and is about half the cost of a new fixture.” Unlike other systems, each Relume light has its own receiver so that, if necessary, even a single light can be controlled by a central location.
“LED is for real, it’s here to stay,” says Lipsey. “There’s a McKinsey study that says 60 to 70 percent of all general lighting will be LED within the next five years. The worldwide market is between $70-$75 billion, so there’s a lot of opportunity.”