Steven Turner, Senior Management Analyst at the City of Casa Grande
24 May 2017
The City of Casa Grande needed to find a solution to the increasing costs for street lights. Increasing electricity and maintenance costs were creating an unsustainable strain on the City’s general fund. It had been a few years since the City of Casa Grande investigated switching its street light system from High-Pressure Sodium (HPS) to Light Emitting Diode (LED). At that time technology was not to the point where it would have been financially beneficial to the City. The LED technology didn’t last as long, they were not tested to the Arizona heat standard, and the warranties were not as long as they are today. However, the City recognized the need for a change to the street light system or it could not sustain its current direction.
Energy efficiency isn’t a new concept to the City of Casa Grande as it has been at the forefront for solar innovation. In fact, the City of Casa Grande was the first City to purchase solar panels through a Guaranteed Energy Cost Savings program. In 2015, the City finished its second phase of the 4,500 solar panel project which generates over two million kWh per year. Before that the City completed an energy audit for all city buildings and retrofitted all facilities with new efficient lights, motion sensors, HVAC units, etc. and the City has seen tremendous savings from these projects. City staff knew something could be done to help control the costs associated with their street lights.
Ameresco, the City’s consultant on previous energy efficiency projects, was tasked to find new efficiencies with LED street lights. The City was informed that by using the same Guaranteed Energy Cost Savings program it could see a decrease in energy consumption by 68%, and billed utility costs reduced by 39%. While these savings are significant, City staff was not satisfied and looked for more savings.
Knowing that the new LED street lights last nearly 24 years, City staff looked into bringing the street light maintenance in-house. Previously the HPS street light failures were t0o frequent and large in quantity for City staff to handle, but with the new technology, it was projected to be only 3.5 failures per year. The potential savings from bringing the street light maintenance in-house was too large to pass up. The City is currently on pace to save nearly 70% in street light maintenance costs per year.
The transition from HPS to LED was not without obstacles. Many residents were concerned about dark skies and the recent studies that LED’s are harmful to health. Some municipalities converted their entire street light system only to replace it again due to the color temperatures being too high, potential health concerns and many resident complaints. The City of Casa Grande wanted to learn from others and come up with a solution that was best financially for the City and best for the health and well-being of its residents. After extensive research, City staff received recommendations from both the International Dark Sky and American Medical Associations to use LED street lights with a color temperature of 3,000 Kelvin. The LED street lights used in the Casa Grande project actually removed light by 65% from the atmosphere. This is possible because the light quality from the new fixtures is over 250% better than the current HPS street lights. The American Medical Association said that using LED street lights with 3,000 Kelvin color temperatures minimizes potential harmful human health effects.
There are many unintended benefits that came along with changing the street light system to LED. The Casa Grande Police Department has benefited from enhanced public safety because the light from the new LED street lights show colors truer. The light from the HPS street lights distorted colors and did not show the true colors of an object. The new LEDs show colors as they are intended, which has helped the City Police Department track down suspicious people and vehicles.
Another added benefit is City staff’s ability to wirelessly control the street light network. City staff receives a notification of a pole knockdown, or street light outage and has the ability to brighten the other lights in the area to compensate for the missing light. In case of an accident or other public safety issue, City staff can darken or brighten lights as needed to help with any public safety efforts. This ability also helps staff dim street lights to make the City’s popular Electric Parade an even greater experience for spectators.
City staff understood the change might be hard for some residents. The LED lights provide a completely different look than the old HPS lights. With this in mind City staff worked hard to inform residents through email campaigns, commercials on its government access channel, social media, and press releases.
The conversion process went through with minimal issues. Ameresco converted the street lights on main arterials at night to avoid any traffic restrictions and focused on the residential areas during the day. As expected, the City received a few complaints about the change, but overall responses from the community have been positive.
The City spent $1.7 million to replace its street light network of 3,867 lights. Over the next 15 years the City is guaranteed to save over $3 million.
“The investment we’re making here will definitely pay off in the future in the form of energy savings,” says Larry Rains, City Manager for the City of Casa Grande. “We are proud and enthusiastic about this project that will provide a significant reduction in energy costs over the years.”
A perfect storm of warranties, rebates and improved technology made this an easy decision for the City to pursue this change to LED street lights.
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City of Casa Grande, AZ
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