In 2010, the City of Minneapolis installed 55 energy-efficient streetlights from nine different manufacturers along 46th Street between 34th and 46th avenues. The project, part of Hennepin County’s Minnehaha-Hiawatha Community Works program, was designed to field test various models of light-emitting diode (LED) and induction lights. Over the course of two years, researchers observed, evaluated and compared the performance of various lighting products, detailing the results in a recently published report available on the MnDOT Research Services website.
In a broad sense, the results of the study would appear to confirm what has become common knowledge regarding energy-efficient technologies: while they cost more up front, in the long run they have the potential to save money in the form of reduced energy and maintenance costs. The study also demonstrates that energy-efficient streetlights are capable of producing adequate light output and are well-received by residents.
However, if the big question is whether energy-efficient streetlights can save local governments money, the answer is somewhat complicated. The study found that both the levels of light ouput and the amount of time it takes to recoup costs varies significantly by product. Page 16 of the report (page 25 of the PDF) features a table comparing various products’ light output and estimated payback time. With one notable exception, the results show that products with the highest light output (i.e. the highest performers and therefore the most desirable) tend to also have the longest payback time. The amount of time it takes to generate a cost savings from energy-efficient streetlights can be as short as 2.6 years or as long as 24 years, depending on the product.
Some other interesting tidbits from the study:
- Researchers observed operational cost savings of 50-75 percent, depending on the product.
- Eighty percent of the savings came from reduced maintenance costs, while only 20 percent came from reduced energy costs.
- In a survey of area residents, 76 percent responded positively to the new, energy-efficient lights.
The study demonstrated that energy-efficient streetlighting is a feasible option for local governments, with the caveat that agencies need to research lighting products thoroughly before making a choice as to which one to use. Ultimately, considering the ever-decreasing cost of LEDs, the use of energy-efficient streetlighting technologies is likely to grow.