LED streetlight test puts Seattle arterial in national spotlight

Mar 6, 2012

Later today, road crews will shut down a 15-block stretch of a major arterial in Seattle’s Ballard neighborhood. For three nights, the city is testing the use of new LED lighting to replace old-fashioned street lamps.

The study is part of a regional effort that could set the standard for more energy efficient streetlights across the country.

How many city employees does it take to change a street lamp in Ballard? In this case, a lot.

“There’s actually a little army of people that are helping with this study,” including Seattle City Light workers, the city’s department of transportation and several regional utilities, says Mark Rehley.

He’s with the Northwest Energy Efficiency Alliance, which is overseeing the data collection during the street closure.

Ultimately, “we hope that 1.7 million lights around the northwest will get changed,” Rehley says, since cities around the nation have street lamps that are reaching the end of their useful life and will need to be replaced.  But to do that, they need to agree on new standards for the lighting.

Quality of light

They have 180 test subjects who will walk or ride along the closed street in Ballard after dark and push buttons indicating when they can recognize certain objects, under new LED street lamps.

The quality of LED light is different. It’s got a cooler feel and less glare. Some people find it similar to moonlight. But it’s more focused and energy efficient.

Rehley says the data collected in Ballard will help a society of engineers set new standards for the region and potentially for the nation.

“And the studies that have been done in the past have shown that even at much lower volume of light, subjects were able to identify objects further away, with LED lighting,” Rehley says.

That makes the lighting safer, which is the biggest priority when it comes to streetlamps.

But they also save lots of energy and money, says Seattle City Light’s Edward Smalley.

“Matter of fact, with the 20,000 units we’ve already installed, we’ve saved over a million dollars that would normally be billed to the city of Seattle’s general fund,” Smalley says, adding that that million dollars “represents about 8 – 10 police officers and their vehicles, on the road."

Less expensive, better for police

He says cities around the country have also found police work more effective under LED lighting, because details such as colors are more accurately recognized and reported, preventing errors, like a light blue car being mistaken for white.

Seattle City Light started switching street lamps to LEDs in 2007 and got a federal grant in 2009, which was used to kick start installation in residential neighborhoods all over they city.

Now they’re getting ready to do more major arterials. They're also installing improved controller technology that allows them to save even more energy, by dimming the lights at certain times.

They say the solid state LEDs use about 50 percent less energy than the lamps from the 1980s that they are replacing. And the new controllers could improve the energy efficiency by another 25 percent.

They think the city can save $4 million a year by switching all its street lamps over to LEDs, and save an average of 115 megawatts a year – or enough to power 87,000 households.

Note for residents: the street closure in Ballard is on 15th Ave NW between NW 63rd and NW 80th and will take place for three nights from 8pm to 1am, starting tonight (March 6th.)