To support a citywide Green Phoenix Initiative, the capital of Arizona plans to convert each of its high pressure sodium (HPS) fixtures to LED street lighting as well as use the more efficient fixtures for all street lamps installed in areas of new construction.
With new and continued construction and development throughout the city, Phoenix officials knew they had to identify a means for combatting subsequent skyrocketing energy costs. Partnering with electrical utility Arizona Public Service (APS), the city researched alternatives to standard high intensity discharge (HID) systems, comparing energy consumption, light intensity, color and ambient temperature—and overall value, said Jason Fernandez, principal engineer technician with the Phoenix Street Transportation Department.
“We reviewed more than two dozen fixtures and conducted controlled testing for nearly four years to examine characteristics such as lighting patterns, overspill and uplighting,” Fernandez said.
APS led additional testing of fixtures in the field and installed five of GE's Evolve™ LED street lights, including the ERS1 and ERS2 fixtures, he said. The fixtures' heat sensitivity especially was a consideration for Phoenix, a city with average summer temperatures of 105 degrees and high temperatures often above 120 degrees.
“GE's Evolve LED street lighting is our new standard and will be installed anywhere a fixture needs replaced or where new construction and capital improvements occur,” Fernandez said. “Additionally, with the energy and cost savings we experience from each new fixture, we're putting that money toward our investment for more LED street lights.”
With 700 anticipated to be converted by year's end, the city is installing GE's Evolve LED Roadway Scalable Cobrahead fixtures.
Results & Benefits
Officials anticipate the city's overall conversion to LED street lighting along its more than 4,800 miles of public streets will be completed around the year 2020, yielding a projected 60 percent savings in energy use compared with HPS. This will save the city more than $57,000 in energy costs, plus an additional $41,000 in anticipated maintenance savings from the Evolve LED Roadway Scalable Cobrahead fixture, which offers more than 11 years of reliable service, based on a rated 50,000-hour lifetime and 12 hours of operation per day.