TECHNOLOGY / STREET & AMENITY LIGHTING
says Andries Conradie of Engineering Services
Company Motla. The fact that the efficiency of
today’s LED lights don’t exceed metal halide lamps
is another reason why adaption is slow, Schleritzko
claims. “The fact is that the efficacies of LED light
sources are currently at par with the metal halide
lamps. Therefore, no meaningful energy saving,
expressed in energy consumption per kilometre
of road lighting, can be expected.” Both Con-
radie and Schleritzko were therefore involved in a
pilot-project recently to obtain data. “We chose
three adjourning streets in a residential area, near
Johannesburg, that were illuminated by LED street
lights. Each street was illuminated by LED lights
from a different producer,” Conradie explains. The
original mercury vapour lights used 125 watts while
the LED lights that were tested ranged from 24
Watt to 41 Watt. “Although we are still busy writ-
ing our final report, I can say that the lighting lev-
els are acceptable but you lose some uniformity.”
JUST A MATTER OF TIME
The question about how long it will take before
LED will be introduced seems to be met by mixed
responses. James Jooste of Light-Be, a South
African partner of Philips Lighting, and also par-
ticipant in the Ekurhuleni Municipality trial and
member of the board of the Illumination Engineer-
ing Society of South Africa, believes that it will
take a while before South African roads will be
illuminated by LEDs. “LED lights have a long way
to go before they will be financially viable and
thus interesting enough for use in street lights,”
he says. Schleritzko believes it is only a matter of
time before the technique will be fully adapted.
“Since vast amounts of R&D funds are invested in
LED technologies, LED light sources will become
increasingly more efficient and, in view of the
increasing international competition, less costly,”
he says. The Beka Managing Director also expects
that standards will be improved and that they will
force municipalities to switch to LED. “New light-
ing standards regarding Mesopic Vision, which will
be adopted in near future, will make High Pressure
Sodium light sources less attractive in low level
lighting applications, such as residential areas or
parks. Therefore we believe that road and amenity
luminaires that are presently using light sources of
up to 150W Metal Halide, will be largely replaced
by LED light sources. This could happen within the
next three to five years.”
Whether this will be the case remains to be seen.
On the website of Stefan Wiswedel’s Sustainable
Energy Africa it is claimed that if Cape Town would
convert all of its streetlights to LEDs, the city
could save 30% on the electricity used for public
lighting. This would work out to a staggering 27
Million kWh per annum, a significant reduction
for a city that works hard on its ‘green’ image.
“But until they become cheaper, LEDs will be a
nice feature for rich entities and cities to reduce
their carbon footprint. But not to save electricity,”
James Jooste warns.
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