An LED street-lighting transformation is on the rise. Cities considering smart street-lighting advancements more than doubled to 59, according to the Northeast Group LLC, a Washington, D.C., smart infrastructure market intelligence firm. The firm reported that major U.S. cities pursuing a conversion to LED has grown from 107 in 2018 to 185 today. Chicago is one of the leaders as it wraps up the fourth and final phase of its Chicago Smart Lighting Program. Begun in 2017, the program represents the largest municipal-owned project in the country.
The Chicago Department of Transportation (CDOT) is responsible for the city’s public way infrastructure. Lighting has been a major component of a much-needed public services upgrade, and LED was the answer.
“We discussed capital costs, utility costs and maintenance,” said Oswaldo Chaves, deputy commissioner at CDOT. “After studying what other cities had done, we came up with a program to replace 80% of our city lighting with LED.”
By 2021, the city will have replaced an estimated 270,000 high-pressure sodium (HPS) fixtures with energy-efficient LED counterparts in streets, alleys and viaducts. Simultaneously, the project has been developing a mesh network to streamline lighting management, maintenance and repairs and provide a foundation for other forays into smart city management.
“We surveyed the community and created street demo installations to gather community feedback on the LED light,” Chaves said. “The demos allowed us to evaluate and choose the best fixtures. We also looked at color temperature and chose 3,000K. For our cobra-head light posts, we decided to change out the entire HPS fixture with LED.”
“What a difference this lighting has made in nighttime safety for pedestrians and drivers alike,” he said. “We have also gotten positive feedback from the Chicago police department, who tell us the color rendering and clarity of images on video from cameras is greatly improved.”
The city estimates an individual HPS to LED fixture replacement only takes about 15 minutes. LED lamp life should extend two to three times that of HPS. The electrical contractor responsible for the swap out is John Burns Construction of Orland Park, Ill.
Many of the light posts used for residential lighting feature an added coach light, attached as an arm several feet below the cobra light. Instead of replacing them, the city retrofit these lighting fixtures.
In the switch to LED, the city expects a 50% energy savings, yielding total dollar savings of approximately $100 million over 10 years. Chaves said energy savings have already hit 40%. It may be too early to claim maintenance savings, but Chicago’s LED installations have required minimal upkeep so far. By the third phase, street-lighting complaints had already fallen to less than 1%, he said.
Incentives have provided savings as well. Planners for the Chicago Smart Lighting Program approached the Illinois Commerce Commission as they considered street-lighting improvements. The incentive funding helped make the program very cost-effective, Chaves said.
In addition, through the city’s utility, Commonwealth Edison, Chicago is earning rebates that subsidize the cost of the LED conversion. Rebates are projected to total $35 million over the four-phase conversion period. The electricity savings and rebates are expected to offset most of the $160 million cost of the modernization.
Taking on a new network
“It was determined that pursuing controls and LED replacement together would be more cost-effective,” Chaves said. “It [helped] us reduce maintenance with the network controls in place. For example, nodes have not had to be cleaned beyond what precipitation provides, which has kept sensors functioning well. We can also now look at our network, pinpoint problems and get a work order out before a lighting complaint. Analyzing the data generated by our streetlights allows us to be more predictive and analytical. Technicians and maintenance staff are equipped with tablets, allowing them, for instance, to access and control circuits (e.g., lights turned on and off).”
The project has also helped address aging streetlights and cabling. By project’s end, the city will have replaced 270,000 street, alley and viaduct lights with LED lighting and installed more than 293,000 linear feet of permanent aerial cabling.
The city turned to Ameresco Inc., a national energy services provider, to help formulate and manage the city’s networked LED lighting effort. The firm, based in Framingham, Mass., evaluated the city’s network system, helped engineer the communication of light post nodes to the network and advised how to handle the gathered data in an analytical way.
“The City of Chicago’s Smart Lighting Program addressed a much-needed infrastructure upgrade for a variety of aged fixtures in both historic and nonhistoric areas of the city,” said Louis Maltezos, executive vice president at Ameresco. “Even in the project’s earliest planning stages, the city was considering the long-term benefits of integrating smart city technologies into the implementation. One of the goals was to use the mesh network being installed for the streetlights for additional smart city/array of things technologies.”
Looking to tomorrow
Maltezos noted Chicago has taken “incredible strides” in evaluating early-stage technology that will build out a smart city system. Discussions continue with vendors to determine the best fit for integration into what will be an evolving mesh network.
“The network is flexible and can certainly handle more data,” Chaves said. “We are working to better manage traffic signals within the network. We are also exploring water management where our customer water meters can talk with assigned nodes on our streetlights and communicate back to the network.”
Maltezos feels as Chicago goes, so will others.
“The success of the City of Chicago’s Smart Lighting Project will likely be a turning point in the future of smart lighting projects across the nation. This type of installation could become the norm instead of the exception as the technology becomes more widely adopted and costs continue to drop through technology innovation,” he said.