* LEDs optimal for always-on public lighting
* The longer they burn, the shorter the payback time
* Old bulbs yield 16 lumen per watt, LEDs 130 lumen
* LEDs still too expensive for residential use
By Maria Sheahan and Jens Hack
FRANKFURT, May 31 Light-emitting diodes are
taking over public spaces, saving thousands of euros in energy
costs, although the price will deter households from making the
switch for some time.
LEDs are up to eight times more efficient than incandescent
bulbs used in most homes but are still at least 10 times as
The more expensive a lamp, the longer it needs to burn to
write off the price, so it is more viable to use them in streets
and hospitals than in homes where lights are off more than on.
The town of Langen on Germany's North Sea coast has done the
sums and two years ago became the first in Europe to replace its
2,583 street lights with LEDs at a cost of 1.7 million euros
The town now spends about 79,000 euros a year to run its
street lights - more than 60 percent less than before.
"The best kind of power is the power that you don't need,"
Mayor Thorsten Krueger told Reuters.
As LEDs need replacing about every 12 years rather than
every 3 to 5 for conventional lamps, maintenance costs are also
down 94 percent. The Philips lights Langen uses are
about 75 percent more expensive than regular street lights, the
town hall said.
New EU legislation to halt the sale of mercury street lamps
from 2015 means more towns will follow Langen, which funded
almost all of the switch to LED with a low-interest loan from
state development bank KfW.
Consultancy McKinsey sees the LED market growing to almost
65 billion euros by 2020 from 9 billion in 2011, boosting sales
at leading suppliers like Philips, Osram and Cree
While the efficiency argument is clear, the cost of LEDs is
still higher than other alternatives to incandescent bulbs, like
compact fluorescent lamps (CFL), as semiconductor-based LEDs are
made using expensive materials like sapphire and rare earths.
McKinsey estimates that an LED bought for the home in 2011
will take until 2025 to pay off. But by 2020, prices will have
dropped and performance improved so much that it will take only
half a year.
That assumes lights are on for four hours a day. In offices
and hospitals, where lamps burn longer, payback is shorter.
The 587-room Marriott hotel in Frankfurt spent about 13,000
euros to replace lights in corridors and stairwells, which are
on 24 hours a day, and expects to make that back within seven
"It's not just the reduced electricity consumption that
saves money but also the fact that the lamps don't create as
much heat," said Andreas Grosse, the hotel's engineering
director. "We're saving thousands of euros on air conditioning."
Lighting companies are trying to cut LED prices by
developing technology that uses silicon instead of sapphire in
the manufacturing process, although for now silicon-made LEDs do
not perform as well.
Sapphire prices have fallen by a third in the last year, but
that has still not brought final prices down enough.
Osram plans to cut prices next month but its bulbs will
still be just under 10 euros against less than 1 euro for 40
watt incandescents. Cree sells comparable LED bulbs for less
than $10 in the United States.
"LEDs are not becoming as cheap as traditional bulbs anytime
soon," Osram Opto Semiconductors CEO Aldo Kamper told Reuters.
But there are already advantages for those with money.
The Rijksmuseum in Amsterdam switched to LEDs because of
their low heat, lack of ultraviolet rays and range of spectrum
that highlight details almost unseen under traditional light.
"For example, there is a little sculpture right behind us
made of clay," said Rogier van der Heide, chief design officer
at Philips Lighting. "You can now actually see the fingerprints
of the artist in the surface."