Seattle City Light is converting its residential streetlights from high-pressure sodium lights to light emitting diodes, or LEDs. The decision was made after through evaluation and positive results from pilot projects.
Benefits of LED Conversion Include:
Approximately 48 to 62 percent lower energy consumption
High-pressure sodium luminaires, most installed in the mid-1980s, are at the end of their useful lives and failing. LEDs will provide better service reliability and lower maintenance costs.
Reduction in greenhouse gas emissions:
When LEDs are in use
Fewer service vehicle trips for repairs will mean a reduction of about 20,000 tons of carbon each year
Replacement of luminaires with LED fixtures will provide three to four times longer field life than high-pressure sodium
LEDs are not affected by truck and roadway structure vibration
Better light quality (whiter/cooler color rendering)
Light quality improves safety because of depth of field and peripheral vision enhancements without distorting color
Using the US Department of Energy and the Municipal Solid-State Street Lighting Consortium Retrofit Financial Analysis Tool, SCL has estimated the simple payback for LED conversion of residential lights at 7.7 years. Once all residential fixtures have been replaced, they will save the City an estimated $2.4 million in annual energy and maintenance costs.
LED conversion began north of the Ship Canal in 2010 and continued to the north service boundary. In 2012, the project will convert residential streetlights from the south service boundary to Brandon Street. Remaining work will be completed between Brandon and the Lake Union Ship Canal by the end of 2014. Whenever an existing residential light burns out, it will be replaced by an LED.