Controversy surrounds a recent study called Streetlights for Collector Roads issued by the Lighting Research Center (LRC) at Rensselaer Polytechnic Institute (RPI). It basically said LED lamps were a poor choice for replacing high-pressure sodium (HPS) street lights on collector roads, those that typically carry medium traffic and feed into highways.
Jim Brodrick, Lighting Program Manager at the US Dept. of Energy (DOE) responded in his blog on the DoE site, claiming “a critical error was committed at the outset which affects all of its conclusions. Although I'm sure it wasn't intentional, LRC selected some woefully underpowered LED products to compare with HPS street lamps, and then concluded that LED products aren't competitive because of the high cost of having to purchase additional luminaires and poles to make up for the insufficient light. That's kind of like racing a Ford Pinto against a Chevy Corvette and then concluding that all Chevys are faster than all Fords."
Brodrick further maintained there are plenty of higher-powered LED products on the market that are appropriate for the study application. Had LRC used them instead, they would have produced a higher output and thus given a more fair comparison with the HPS products that were selected.
"The conclusions that LED systems need more luminaires and poles, and therefore have significantly higher first costs, are a direct result of this critical error in product selection, and consequently are baseless<" Brodrick said.
Blogger David Lepage of LED supplier Philips also chimed in. "Another issue I have is with how they (LRC) visually demonstrate how expensive LEDs are (Life Cycle Cost per Mile over 27 Years on page 16). One quick glance at their chart is enough to want to abandon LED luminaires altogether. In some cases, it looks like they’re more than three times costlier to own and operate than HPS! But a closer look reveals that the extreme difference is due, in part, to the fact that the graphics include the relamping of LEDs at 25k hours! They should have stopped the line at 50k, considering this is the bare minimum lifespan most manufacturers advertise for their systems," he wrote.
Brodrick's commentary is on the DoE site here: http://apps1.eere.energy.gov/buildings/publications/pdfs/ssl/postings_10-27-10.pdf
David Lepage's comments can be found here: http://www.lumec.com/blog/index.php/2010/11/05/streetlights-for-collector-roads-report-a-trip-back-in-time/