Chasing the Holy Grail of LED street lighting

San Francisco Civic Center LED Street Lamps. Courtesy of BetaLED.

The current Holy Grail of lighting today is arguably LEDs (light emitting diode). But lighting industry sales representatives are surprised by how many LED street lighting units have been returned lately. We communicated with two users of this technology who describe the LED market as so dynamic, changes are showing up almost monthly.

Ed Smalley, streetlight engineering manager of Seattle City Light, confirms that, “A lot of upstarts are jumping into this business.” Smalley is probably America’s #1 advocate of LED street lighting, since the U.S. Department of Energy (DOE) designated Seattle City Light last year to lead its national effort to educate end users about energy-efficient, solid state LED street lights.

Smalley is also director of DOE’s Municipal Solid State Street Lighting Consortium. He’s been an LED promoter ever since he first used them for cockpit instrumentation on Boeing airplanes. “After 23 years of witnessing their performance, I feel relatively optimistic about LEDs,” Smalley says.

The LED category has some distance to go before it achieves uniform quality and dependability, however. Of more than 150 manufacturers that submitted outdoor LED product documents for review in 2009, Smalley says, Seattle City Light “settled on 12 to sample, chose five, and approved two to buy.”  They’re also testing 6-7 more for future purchase. That tallies to a 1 to 3 percent success rate for new manufacturers.

On indoor LED lighting, "The technology is improving quickly, markedly, but not keeping up with the hype," says Eric Strandberg, Senior Lighting Specialist at the Lighting Design Lab, also in Seattle, “Marketing departments are not communicating with engineering departments. If you run the calculations for product engineering and photometrics, they’re usually accurate, but those often don’t appear in the marketing piece that people read, so claims are made about LEDs replacing other lighting products, which aren’t quite true."

Strandberg also notes that while LEDs provide light and save energy, you can do the same things with non-LED products. Strandberg finds public and private institutions starting to specify uses of LEDs only, without running the numbers to find that alternative technologies will work as well as or better for the same purposes. “They should be specifying the ‘best performing instrument’ instead, so they don’t ignore other products that are just as good,” he says.

As a general rule, the more expensive the lighting instrument, the better its quality will be.  Strandberg finds the public’s general indifference toward using fluorescent lighting at home “dismaying and puzzling”. Instead, he says, “There seems to be this mad scramble to use all things LED, when the quality and energy savings haven’t even been close to decent CFLs (compact fluorescent lamps).”

Strandberg notes that, for most screw-in LED bulbs priced in the under-$25 range, “heat management is a huge problem, because they try to push too much current through,” and that often burns units out before their rated lifetimes. “A CFL will usually do as well as or better than an LED (in that price range), and provide higher output for much less money.”

Performance tends to be better at higher price points, like those of outdoor LED commercial lighting. However, even the top end prices have dropped 25 percent in the past year, says Smalley. The two LEDs that passed Seattle City Light’s rigorous five-step testing process were LEOTEK and BetaLED. Seattle has embarked on LED evaluation because of the City’s aging, 25-year-old amber, cobra head, high pressure sodium (HPS) streetlight inventory needs a massive upgrade. 

Seattle City Light started swapping out HPS for LED in 2007 and expects to finish the job on all its 41,000 residential HPS units by 2014. Since the LEDs are 50 percent more energy efficient and last 10 years longer, they'll reduce operations and maintenance costs, and eventually save Seattle $2.4 million per year. LED street lamps also offer better lighting quality.

“People like that they can actually distinguish colors under LED light -- of cars, shirts, basketballs,” Smalley says. The potential benefits, and savings are attracting other utilities to LEDs too. Vancouver, B.C., Portland, and San Francisco are all testing LEDs, and Los Angeles has already installed 60,000.

Seattle City Light’s five-year warranty calls for its LED manufacturers to fix or replace failed units. So far, this has happened to fewer than 12.

“The odds of an individual (high-quality) LED failing are 1000 to one,” says Smalley.  “More likely the problem will be workmanship, or another electronic component.”

Another advantage is that Seattle City Light must recycle all of its old HPS streetlights through certified and approved metal and hazardous materials recyclers. By contrast, LED streetlight fixtures contain no hazardous components, and no lamps to replace, so they can be 100% recycled.

For the first time in history, a single light source, LEDs, shows the potential to satisfy the four main needs of public, commercial, industrial and retail lighting: illumination performance, controllability, and operational efficiency. In street lighting alone, the potential market amounts to 38 million units nationwide.

This is the reason that new designs, performance improvements and cost reductions are showing up almost monthly. Smalley doesn’t believe there is a one-size-fits-all solution for all lighting challenges, and says that “each application needs to be evaluated thoroughly, to find the right lighting source." Out of the vast array of products coming to market, Smalley says we can only find the best of them by “doing our homework.” That way, “We can make this work successfully.”