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Getting the LEDs in

May 16, 2008
By MIRIAM MOELLER, Journal Staff Writer

MARQUETTE - Officials from Marquette -the Board of Light and Power's David Lynch and the city's Scott Cambensy -are watching the streetlights in Ann Arbor. In its efforts to save energy, the downstate city is currently testing light-emitting diodes -or LEDs -in its globe streetlights. These components are supposed to cut electricity use in half, according to the City of Ann Arbor Web site. The city plans to replace 1,000 more streetlights with LEDs. "We've been kind of watching this," said Lynch, the BLPs superintendent of distribution. Depending on the success of the LED trial in Ann Arbor and other cities in the United States, he said Marquette may follow suit. In the meantime, Lynch has been working together with Cambensy, director of public works, on finding ways to reduce the city's energy use and save money by using different types of alternative light bulbs. Lynch said in the mid-1990s, the BLP switched the 189-watt incandescent light bulbs in city streetlights to 100-watt high pressure sodium bulbs. These bulbs -still in Marquette's streetlights today - cut energy use in half at the time. "It's good, but if we went to an LED-type, we could cut energy use by 75 percent," Lynch said. "They're going to be highly efficient." But switching to LED lights might not be simple. Lynch said the technology for LEDs that could be used for streetlights is still not completely developed. "It has to do with the technology to make a LED with enough intensity to be used for street lighting," Lynch said. Streetlights have outputs in the area of 25,000 lumens - a measure of light - for a 250-watt high pressure sodium) fixture, and around 9,000 lumens for a 100-watt fixture. For example, a 100-watt incandescent produces only 1,750 lumens, he said. "So LEDs are fine for lower lumen output lighting now, and are being improved for use in high lumen output installation such as street lighting," Lynch said. In Marquette, Cambensy said traffic lights, pedestrian traffic signals and the downtown's Christmas lights have already been replaced with LEDs. "The big thing with the traffic lights is, not only do they use less energy, but they last longer," he said, adding that replacing the bulbs was part of a two-year project that should be completed soon. Cambensy has also been replacing interior lights in the municipal service center on Baraga Street and at city hall. "Interior lights at the Municipal Service Center were converted from incandescent bulbs to CFLs (compact fluorescent lights) and from T-12 to T-8 fluorescent ballasts over a period of a year and a half, starting in early 2006," Cambensy said. "The T-8s actually emit more light than the T-12s do and they consume less energy." A total of 235 T-8 lights were installed at the service center, Cambensy added. The lights have a life expectancy of about two to five years depending on usage and the return on investment is about three years. "After that you'll see the energy savings," he said. Lights in city hall, including those in a chandelier, were also switched to more energy efficient ones, Cambensy said. "It is probably five times as bright in there as it used to be," he said. Cambensy and Lynch continue to monitor new lighting trends and hope to be able to switch to more energy-efficient streetlights as soon as the new technology is available.

Article Photos

Scott Cambensy, the city’s director of public works, shows two types of fluorescent ballast lights. The smaller kind, T-8s, emit more light and use less energy than the bigger ones, called T-12s. (Journal photos by Miriam Moeller)



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