Monday, February 8, 2010

Recent Trends in Solid State (LED) Lighting

The acceptance of Light Emitting Diodes (LEDs) as the preferred lighting device continues to grow in all sectors throughout our country, but especially in municipalities. U.S. cities are seizing upon LEDS as a viable strategy to “Go Green”, particularly in applications where low maintenance is more important than lower initial costs.

According to an article entitled “U.S. Cities Go Green with LEDs”, in the Optical Society of America’s (OSA) February issue of Optics and Photonics News (OPN), cities as well as public and commercial institutions are demonstrating the use of LEDs to realize long term cost savings and reduce pollution in the operation of traffic lights and street lighting. Although LED’s are still more expensive than fluorescent lights, their initial costs are offset by their higher efficiencies and longer lifetimes. Maintenance costs to replace failed lighting are very expensive in street lighting and traffic lights. And LED’s don’t usually “fail suddenly”, like incandescent and fluorescents. When they begin to fail their light production usually drops about one-third, which means that there is more time to schedule and coordinate repairs.

James Brodrick, manager of the DOE’s solid state lighting program, claims that the use of high efficiency LEDs could reduce U.S. energy consumption for lighting by over 30% in two decades, which would eliminate the need for 44 power plants generating 1000 megawatts each, and cut the equivalent of 47 million automobiles’ greenhouse emission. LEDs are also more efficient in outdoor lighting because they are more directional and can be applied where they are needed. The clean, uniform lighting provided by LEDs also improves visibility.

All new traffic signals now use LEDs, which provide a cost savings of approximately $48/year, due to reduced maintenance and the fact that LEDs produce the desired colors, rather than having a broad band source that has to be filtered, like fluorescents and incandescents.

The DOE is encouraging the use of LEDs by funding municipalities and educational institutions for demonstration and test sites. (Visit http://www.ssl.energy.gov/ for more information.) The OPN article, cited above, describes several successful examples of DOE-funded initiatives.

LED use is also growing in home use, particularly in outdoor lighting. But the cost and reluctance to switch to a somewhat different lighting effect have delayed widespread use like municipalities have experienced. “The Energy Independence and Security Act of 2007, which set efficiency standards for light bulbs, is also helping to promote LED use. Traditional incandescent bulbs do not meet the standards that go into effect in 2012”, Brodrick said. “By 2020, advanced incandescents will fall below the standards as well. Only CFLs and LEDs are likely to meet the 2020 standards.

OP-TEC continues to follow LED technology advances in lighting, in order to anticipate the need for new technicians in this field. So far most of the production and installation jobs appear to be at
the craft level.

Questions or comments? Please contact us!

Click here to read the full OPN article, "U.S. Cities Go Green with LEDs."

Click here to visit the DOE's Solid State Lighting website.

4 comments:

Mike Qaissaunee said...

Dan,

Have you seen the stories of LED traffic lights that have been obscured by snow. Apparently, the heat from traditional traffic lights was sufficient to melt the snow, but obviously that is no longer the case with LEDs. Some proposed solutions that I've seen include retrofitting the lights with a clear dome to prevent snow from accumulating.

Here's one story describing the problem:
http://www.engadget.com/2009/12/17/led-traffic-lights-dont-melt-snow-do-cause-accidents/

Best regards,
Mike Qaissaunee

Dan Hull said...

I have also seen comments about this problem. Adding a dome sounds like one possible solution. Do you know if this has been tried? And whether it worked?”

Mike Qaissaunee said...

From http://www.autoblog.com/2009/12/16/unintended-consequence-of-technology-new-led-traffic-lights-can/

Municipalities around the country are taking different steps to keep their signals shining brightly in the face of Mother Nature. Crews in St. Paul, Minnesota, use compressed air to keep their lights clean. In Green Bay, Wisconsin, city workers brush the snow off by hand in a labor-intensive process. Until a fix arrives, it is best to take the advice of Dave Hansen, a traffic engineer with the Green Bay Department of Public Works. Treat a blocked signal as if the power is out. "If there's any question, you err on the side of caution," says Hansen.

and from http://ledinsider.wordpress.com/2010/01/08/led-streetlights-in-snow-need-plastic-cover/

The solution is to install clear plastic, convex covers on the streetlights

Anonymous said...

Organic light emitting diodes (OLEDs) provide another solution in displays and home lighting.

Andrew