In municipalities around the county, light-emitting diodes are slowly taking the place of older, high-pressure sodium lighting systems for outdoor streetlights. This new wave of LED streetlights boasts the benefits of long life, reduced light pollution and saving cities money.
During 2014, lighting for commercial and institutional buildings and streets and highways burned about 262 billion-kilowatt hours, according to the U.S. Energy Information Administration. Lighting is one of the larger costs for a city. The change to LEDs can help.
Over the past couple of years, Clark Public Utilities has conducted several LED streetlamp pilot programs.
“LEDs are the emerging streetlight technology,” said Bill Hibbs, commercial programs manager at Clark Public Utilities. “As the cost of LED street lighting continues to drop, we will continue to see wider adoption and see their use increase in more decorative lighting, like the acorn post lamps planned for the City of Camas LED street lighting conversion.”
Scientists claim stray light pollutes the night sky, making it more difficult to see the stars, disrupts ecosystems, effects health and wastes energy. To better focus outdoor light, photometric software helps streetlight designers spot under- and over-lit areas for pilots. Then they can adjust cobra heads and acorn style LED streetlights onto parking lots or sidewalks without light spilling over into home windows or diffusing into the sky.
LEDs are efficient emitters of light. One LED produces between 100 and 150 lumens per watt. Lighting technologists expect 200 lumens per watt in the future. Being directional, they waste less light and decrease light pollution. With street lighting a major cost for cities, directing light to the right places, reduces operating costs.
Local upgrades
About a year ago, an American Recovery and Reinvestment Act grant funded the replacement of 50 street lamps in Battle Ground and 200 in Camas and Washougal.
Around the same time, a grant from the Washington State Transportation Improvement Board funded a Ridgefield phase-1 pilot replacing more than 350 “cobra heads” with LEDs. The City of Ridgefield will maintain the lights.
This summer, Camas will embark on a second project to replace 3,250 streetlights in the city and its subdivisions. A $500,000 Energy Efficient Grant from the Washington State Department of Commerce is paying for part of this $2.4 million project.
“We’re in the design and procurement stage right now, but plan to complete the project by year’s end,” said Steve Wall, Camas public works director. The city plans to retrofit both cobra heads and decorative or acorn-style lights.
“As LED technology gains greater adoption, we will continue to assist with projects in the county that prove their energy savings, cost effectiveness and reliability,” said Hibbs.
LEDs are semiconductors that emit light in the white color range between 4000 and 4400 Kelvins, a measurement of heat. Lamp packaging holds each chip and phosphor to stabilize its colors. Their packaging protects both and determines how long the lamp lasts. Many outdoor LEDs can burn for more than 50,000 hours.
Their longer life means fewer replacements and less maintenance. Their durability and vibration resistance makes them ideal for bridges, tunnels and overpasses. Additionally, LEDs are more controllable and dimmable, giving designers more flexibility when creating their lighting design.
The technology continues to improve and become more affordable. In the meantime, these pilot projects will provide local cities and the utility with useful information about the durability and energy saving benefits of LED streetlights.
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.
