Last night (Tuesday, June 20), City Council approved a contract to retrofit Knoxville’s nearly 30,000 streetlights with light-emitting diodes (LEDs), setting the City on a path to save $2 million a year while greatly reducing carbon emissions.
Mayor Madeline Rogero proposed the project in her 2017-18 budget. “Our streetlights are one of City government’s largest energy users, accounting for nearly 40 percent of our total municipal electricity consumption,” the Mayor said.
The Office of Sustainability, working with KUB, developed the plan to cut in half the approximately $4 million the City currently spends each year to operate and maintain the streetlight system.
Council approved a $9,548,215 contract with Siemens to perform turn-key design and installation services for the new LED lights, beginning with an extensive design phase that includes test/demo installations of new lights for evaluation by the City and public stakeholders.
Once the design phase is complete, Siemens expects to begin installation of new lights across the city in late 2017 or early 2018. According to the contract terms, all work is expected to be complete by June 30, 2019. Siemens was selected to provide the turn-key design and installation services for the Streetlight Replacement Project through a competitive procurement process that began in fall 2016.
By retrofitting Knoxville’s streetlights to LED technology, the City will save money, reduce energy use, and take a major step toward exceeding its goal of reducing municipal greenhouse gas emissions by 20 percent by 2020. With anticipated energy and maintenance cost savings of $2 million annually, the investment will pay for itself in less than a decade.
Concurrent with the design of the new LED lights, the City will also work with KUB to arrange to reimburse the utility for approximately $5 million of past infrastructure investments in the lighting system.
Currently, Knoxville streetlights are outfitted with high-pressure sodium (HPS) bulbs, which have an average lifespan of 24,000 hours. LEDs last considerably longer, with many fixtures rated to operate for 100,000-plus hours and backed by 10-year manufacturer warranties. LEDs use much less energy to provide the same amount of light as HPS bulbs, thereby offering energy savings of upwards of 50 percent.
LEDs also give off a whiter light than traditional HPS bulbs and shine light more directionally, so that light goes where it is needed.
“This project will help us improve the overall design of our lighting system,” says Office of Sustainability Director Erin Gill. “Instead of illuminating the sky and trees with an orange glow, we can focus light where we need it: on streets and sidewalks. The clear, whiter color of LED light provides better visibility and color rendering than HPS bulbs, making it easier to see people and objects in the roadway.”
Gill adds that the street light replacement project will follow guidelines and best practices outlined by the American Medical Association (AMA) and the International Dark Skies Alliance. These organizations recommend luminaires with a color temperature of approximately 3,000K (degrees Kelvin), comparable to a 100-watt halogen bulb, as opposed to the cool blue light of LED headlights (6,400K) or a bright compact florescent bulb (4,000K). The majority of lights will be fully shielded fixtures that emit no light upward, and backlight control shields may be implemented where needed to help direct light away from nearby windows.
“These new LED lights, over 50 percent more efficient than those currently installed throughout Knoxville, will not only provide residents with better visibility and safer streets but will significantly reduce the impact lighting has the city’s bottom line,” said Marcus Welz, CEO of Siemens Intelligent Traffic Systems. “Infrastructure improvements like this are excellent ways for cities across the country to improve quality of life for their citizens, save a significant amount in energy costs and meet their sustainability goals.”
During the design phase, there will be multiple opportunities through public meetings and the demonstration installation for local residents and businesses to review and comment on the new proposed lighting. Additionally, project staff can be available to discuss the project and LED lighting plans with neighborhoods and other community groups. As the streetlight project progresses, the City will post updates online at www.knoxvilletn.gov/LED.