Downtown Pearl Street on Tuesday, Sept. 28, 2021. Credit: Timothy Hurst

Boulder’s streetlights typically don’t spark much conversation, but a recent city proposal has thrust them into the middle of a policy debate.

At this week’s Boulder City Council meeting, members will discuss a plan to acquire all streetlights on public property owned by electric utility Xcel — which account for the vast majority of Boulder’s 4,540 streetlights — and upgrade them to smart LED models. 

According to a memo prepared by city staff, Boulder says the acquisition project would save the city $13.6 million over 20 years and reduce annual electric consumption by 2.3 million kWh (kilowatt-hours) – equivalent to the electricity used by about  200 homes in a year. LED lights are more energy efficient than HPS (high-pressure sodium) lights, which are used by most Xcel-owned fixtures in the city. The memo estimates conversion would reduce streetlight energy usage by 70%.

In addition to energy savings and emissions reductions, the city says upgrading the streetlights to a newer model would lower Boulder’s energy bill and significantly reduce light pollution, which negatively affects human health along with flora and fauna. 

The proposal comes after voters nixed a decade-long effort by the City of Boulder to form its own electric utility. “The city was exploring this at least 15, if not more, years ago,” Carolyn Elam, the city’s Energy Program Strategy Manager, said of the LED program. “And streetlights were part of what would have been acquired if the city had gone forward with municipalization.”

Acquiring the streetlights from Xcel would give the city autonomy over at least this infrastructure – including repairs. Installing smart controls, which Xcel does not currently offer, would  allow the city to more quickly identify streetlights in need of fixing.

The current repair framework, according to Elam, is much lower-tech, relying on the vigilance of local residents. “In Xcel’s system, someone has to see that light out and call to initiate a work order,” Elam says. “[A smart light] would send an alert to our traffic team so they can affect a repair.” 

A graph from the city staff memo shows how often Xcel Energy repaired a broken streetlight within five days of a service request. Data is from June 2021 to May 2022.

Michelle Aguayo, a spokesperson for Xcel, says service requests have been slowed down by staffing and supply issues due to the pandemic.

“We strive to repair broken streetlights within five days, but in some cases, it’s not possible,” Aguayo said. “Tracking down issues with underground wires can take significant time to locate, and crews have to work with traffic control or acquire permits to complete the work.” 

Smart controls can also help the city reduce energy usage and light pollution by moderating brightness at night. “For example, we may dim in areas we know see significantly reduced traffic after a certain hour at night so we don’t need as much light concentration,” Elam said.

Some nearby cities, including Denver and Westminster, have recently upgraded their streetlights to LEDs, but they decided to allow Xcel to maintain ownership of the lights. Boulder took a different path. That’s partly because, when Xcel began its optional LED retrofitting project in 2015, its LED option was a light with a 4000 Kelvin color temperature, which is greater than the “Dark Sky” recommendation of limiting outdoor lighting to 3000 Kelvin or less.

“Initially, when [Xcel] started offering an LED fixture, it didn’t meet our standards… It was a 4000 Kelvin offering, which, in our view, was not ideal,” she says. “There have been studies that say that kind of color temperature is too harsh, and it can have impacts on nocturnal wildlife. There are issues with how your eyes focus when it’s that bright.” 

The city initially considered two Xcel LED models within Boulder’s acceptable color temperature range, Elam says. However, according to the memo, a 2021 city analysis found that only about 60% of Xcel-owned streetlights could have been upgraded using Xcel’s available models. For the remainder, the city would have to upgrade them on its own or wait for new models to become available.

Aside from color temperature, the memo also points to the issue of cost. The city spends $1.4 million annually on Xcel’s streetlight operation and maintenance. On average, those costs have been rising 9% per year. The acquisition and conversion project will cost the city $7 million, according to the memo. But it also estimates that the city’s overall outdoor lighting costs would decrease by 80% if it took over the maintenance currently done by Xcel, which would still supply the energy to keep the lights on.

The memo outlines multiple different financing plans, including public-private partnerships, should the city council decide to go forward with the acquisition. “Self-financing is obviously the most cost-effective because you’re not paying interest,” Elam says. “The Community, Culture, Safety and Resilience Tax was passed last year. Streetlights were one of the projects that was included as a potential use of the tax revenue.” 

Other options would require the city to spend less upfront, but may lead to smaller savings for the city.

However it’s paid for, a major throughline in what the city sees as the potential benefits of acquisition — from regulating energy use to deciding the ideal light color temperature and providing more responsive maintenance — is more community control over its streetlights. 

“The LED conversion process can often be very challenging in communities because you experience the light differently,” says Elam. “We’re really committed to doing pilots and really working with the community to land on a standard and bring them along… We can engage the community more consistently… than maybe a large utility might if they were to do all the [light] replacements.”

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