The Bigger Picture

Should airports buy environmentally-friendly, but cheaper-to-run LEDs for airfields, or opt for older, cheaper technology?  It’s a question that regularly challenges facilities, as Tom Allett reports.

“You can be as ‘green’ as you like, but if your price for the job is 10% dearer than your competitor you’re not going to get the contract,” the CEO of a European-based airfield lighting company told me three years ago.
Airfield LEDs have been available since the 1990s, but the argument about whether to buy state-of-the-art LED lights, which are significantly more expensive to buy, but are much more energy efficient and therefore cheaper to run, goes on.
The sentiment about price beating ‘green’ qualities wasn’t shared by Jean Luc Devischer, Marketing Manager for ADB Lighting Technologies, who told Airports International: “Only price sells [old technology] Halogen lighting now.  If your airport has very little traffic and limited opening hours, where perhaps you only need to switch the lights on for an hour a day, then I can understand that such a facility might choose to purchase Halogen lights.  Taking taxiway lights as an example, LED versions can be 50%-100% dearer than Halogens to purchase.  If you don’t need to have the lights on very often it takes longer to get your money back through electricity savings.  Nevertheless, there are not many airports where energy consumption isn’t an issue and in our experience LED taxiway lights are already outselling Halogens by a ratio of 60/40 and the split is continually moving in favour of the LEDs.”
Looking at reduced electricity burn from a cost, rather than an energy-saving point of view, Mr Devischer added that a single LED unit will save about €130 (US$166) per year in electricity costs and, taking London’s Heathrow as an example, which currently has approximately 6,000 LEDs in use, equates to an electricity bill reduction of approximately €780,000 (US$1m) per year.
“While LED lighting was a big step forward from the previous Halogen or incandescent luminaries, today things have improved considerably.  Today’s LEDs are about 25% more energy-efficient than their first generation technology.
 
Not just costs
It’s not just about costs though, Mr Devischer admits: “Quality is also a selling point.  The LED’s longer life means fewer replacements; fewer energy-consuming vehicles sent out on runway inspections and fewer runway repair closures.”  In addition, white LEDs are whiter than Halogens which tend to emit a ‘yellowish’ glow.
I asked Mr Devischer about how extreme weather conditions affected the LED lights operational performance; I had heard it mentioned that because LED light produce less heat, they were less able to melt snow that falls upon them.  He explained the lights do produce less heat, but still enough to melt most snowfalls.  However, there is another important factor to consider Mr Devischer added:  “In those countries that have large snowfalls, the temperature is usually far below the perhaps -2°  to 5° lows that we routinely experience in central Europe.
“Further north, it can drop to -20° or even -30° so, even if a light was to melt the snow that falls on it – and perhaps that for a few inches around it – the temperature is so low that the water will just quickly freeze again and cause a build-up of ice that will need to be moved by the airport’s maintenance team, so LEDs’ reduced heat production isn’t really an issue.
“When it comes to making a decision about whether to buy LED or Halogen, it isn’t a single product that is the most important factor, it’s the entire solution; the ‘big picture’, that will decide what an airport purchases.”
 
Power Saving Comparison
ADB LED Taxiway Lights

Product Halogen LED
Straight 45 to 100W 10W
Curve 65 to 100W 16W
Omni 45W 16.5 VA
Elevated 33W 11 VA

 
 
ADB Runway Lights

Product Halogen LED
Rwy C/L Uni 48W 10W
Rwy C/L Bi-Dr 48W 20W
Rwy TDZ 48W 10W
Elev Rwy Edge 150W – 200W 33W