Energy Adviser: Local streetlight efficiency boosted

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Cobra heads sound snaky. And you can find them above your head all over Southwest Washington. But don’t worry, it’s not likely one will drop down and slither away because a “Cobra head” is a common design for streetlights.

Clark Public Utilities recently began the process of upgrading approximately 23,000 high-pressure sodium street and area lights in Clark County to energy-efficient LEDs.

“Customers may see work related to the project beginning in their area,” said Justin Andrews, streetlight specialist for the utility. “DJ’s Electrical Inc. was awarded the contract and will be using bucket trucks and two-person crews for the change-outs.” A longtime utility contractor, DJ’s has qualified line workers who are familiar with the current light styles installed across the county.

The contractor will disconnect the old HPS lights and replace the fixture with a new LED streetlight head. Each change out takes about 15-20 minutes but won’t interrupt electric service to homes or block roadways, according to Andrews. The first phase replaces 13,000 of the cobra head and post-top style lights, and will continue for the next 10 months. The utility is currently planning for the next phases of the LED change-out, which will include other styles of our leased lighting, such as flood and area lights.

“High-pressure sodium lights aren’t directional, and the light often shines into residential windows or spills into private parcels where it’s not needed,” said Andrews. “The life span of HPS lights is about four to six years, so we replace them often.” Last year, the old fixtures spurred about 6,000 calls to the utility countywide. Many outdoor LEDs can burn more than 100,000 hours and the new fixtures are rated to last for more than 20 years.

Andrews said the utility did extensive research to find the right LED fixture replacements. The process has taken many years because technology has continued to improve and prices have decreased significantly. The current LED streetlights have performed well in several local pilot projects and are very cost-effective and reliable. Today, all new lights currently being installed in Clark County developments are LEDs and many cities are requiring LED street lights as well, Andrews explained.

The Light Emitting Diodes used are semiconductors that emit light in the range between 2000 and 6500 Kelvin, a measurement of heat that determines the color — the utility chose 3000 K, a color quality slightly warmer than some municipalities use to light intersections and arterials roadways. The 3000 range helps to control glare and maintain a soft and welcoming quality. Because LED lights are directional, the light can be aimed where it’s needed, onto streets and away from home windows. The result is less wasted light and decreased light pollution. Safety on neighborhood streets also improves with the increased visibility and more accurate color rendering

Street lighting is one of the larger costs for cities and counties. The changeover to LEDs will bring costs down with lower energy costs immediately, and decreased maintenance costs for decades. LEDs are environmentally friendly, contain no mercury and require no special disposal.

Andrews said the utility is tracking the new installations to see if they are meeting the need and reducing the number of calls about burnt out lights. The longer-term result is improved visibility and safety, lower costs, and energy savings that help meet conservation goals.

“We expect the project to pay for itself in about five years and save about 8 million kilowatt hours each year,” Andrews said.


Energy Adviser is written by Clark Public Utilities. Send questions to ecod@clarkpud.com or to Energy Adviser, c/o Clark Public Utilities, P.O. Box 8900, Vancouver, WA 98668.