Light in the Darkness
As we approach the beetle black of midwinter, how many of us take for granted the comfort offered
by our street lights. They help us to carry on our lives as safely and securely as possible. And,
during daylight, have we ever looked up to notice the various street light designs still just about
‘visible’ around town.
Now might be a good time to look. Denbighshire County Council is about to conclude its 10 year
plan of replacing our street lights with new LED
lanterns. Examples of older types are still evident. In
Ruthin, LEDs emerged about eight years ago. The
plan was to convert small pockets of each town at a
time, rather than to complete one in one go.
Denbighshire was off the blocks near the beginning of
the LED lighting revolution, thanks to an ‘invest to
save’ programme that allowed the LED energy saving
to repay a loan used to purchase the hardware.
The programme started with our main roads, all of
which are now converted to various styles of LED
lighting. Main and distributor roads have a noticeably
higher LED classification than housing estates. It was
these residential areas that came next. All converted
are Bro Deg, Erw Goch, Maes Hyfryd, Llawr y Dyffryn
& Maes Hafod, Bryn Eryl, Glasdir, Y Parc, Cae Seren
& Parc y Dre, Canol y Dre, Cae Castan and Parc
Parc Brynhyfryd was previously unique in carrying Ruthin’s only florescent tube lanterns, which were
an emerging and early attempt at energy efficiency. They were ‘whiter’ than their counterparts
elsewhere in town. They provided a reduction in wattage of about 60 per cent, to 36W each. The
Council replaced these florescent tubes in October. The new LED heads bring the power rating to
9W and are the most efficient in Ruthin (previous LEDs for the same luminance run at 13W. In the
last five years, LEDs, already efficient, have improved
by 25 per cent). But the thing is that despite a four-fold
reduction in energy, the luminosity is actually better.
LED white light leaks less, is concentrated on the
footway & carriageway and everything is more distinct
That isn’t always welcomed, though. The clarity under
a ‘whiter’ light can make some people less comfortable
when walking. And, LEDs tend not to wash into front
doors in quite the way traditional lanterns used to—this
may or may not be a blessing. But, the clarity improves
and the carbon reduction is considerable.
It’s still possible in Ruthin to experience the once familiar rheumy, grenadine glow of sodium-vapour
lamps. Soon to be replaced, these orangey 60W lanterns continue to illuminate Ty’n y Parc, Porth y
Dre, Bryn Coch, Bryn Glas, Y Menllis, Bryn Rhydd, Maes Cantaba, The Werns off Greenfield Road,
and Castle Park.
Haulfryn is also unique. Over the previous 15 years or so, its roads are lit by ceramic metal halide
lamps by Philips, somewhat akin in shape to a domestic bulb and previously offering an energy
saving now overtaken by LEDs.
Glasdir’s heritage-style column heads now incorporate LEDs. When installed, they were of a high
pressure sodium type. About a year ago, when the Council adopted the estate’s roads, it included
the pre-conversion to LEDs. But, the unadopted car parks remain lit by sodium lanterns and this is
one area where you can easily spot the grades of illuminance between the two types.
And then there’s the town centre. In the early 1990s, the town’s lamp columns and heads became
similar in design to the gas lamps of yore. Finding LEDs that will fit this design has been a challenge
but it won’t be long till all these are modernised (anticipated January or February 2021).
Currently, the sodium lanterns operate at 100-150W and up to 250W depending upon location and it
is here were the scope for carbon reduction—and improvements in luminosity—is now the greatest.
■ The drivers within LED lanterns are actually able to reduce brightness by 30 per cent during less
busy periods, between 10 p.m. and 6 a.m. This saves further energy and CO2. It’s unlikely that you
will notice this reduction in light intensity.
■ LEDs have an estimated 25 year life. As they get older, the LEDs can dim but the drivers within
the lanterns can compensate for this by increasing the wattage slightly. This, of course, is accounted
for within the energy saving and carbon reduction calculations.
■ Denbighshire changes 1,500 lanterns to LEDs per annum. They started at 18-22W each and are
now 9-13W each, such is the improvement in design even over a five year period.
■ Denbighshire’s street lighting engineers are a multi-award-winning team, having won UK
performance standards almost every year for a dozen years.
An old lantern comes off…