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From Gas Lamps to LEDs

smart-street-lighting

Unless you are a dog , it is unlikely that you pay much attention to lamp posts and street lights.  But they are all around.  There are an estimated 7.5m of them in the UK or one for every 8.5 people.[1]  In 1802, the first exterior gas lamp was piloted in Soho and 80 eighty years later, public illumination began its transition to electricity, with an arc lamp known as a Yablochkov candle [2] after the Russian electrical engineer who invented it.

Depending on the source of the electricity, the strength of the light and the length of the night, each street light costs between 5p and 30p per night to power – or £22-£105 per year.  So that is a bill of around £300-550 million before maintenance costs.  No wonder that councils are looking at ways of reducing the energy consumed in municipal lighting.  Scottish Futures Trust, the oversight body charged with ensuring judicious public infrastructure expenditure in Scotland, found that street lighting accounted for fully 25% of electricity costs in the Glaswegian suburb area of East Dunbartonshire. [3]

Not a surprise then, that in 2014, half the country’s councils were reported to have dimmed their lights and a third to have switched off some street lights completely.[4]  Organisations such as the AA have asserted that, by plunging their wards into darkness, these councils have contributed to pedestrian and other road deaths although these claims are disputed by a study published in the Journal of Epidemiology and Community Health.[5]

The answer seems to be a combination of dimming, reduced hours and energy-efficient lamps and an exemplary initiative is underway in Hampshire where street light energy consumption has been halved in the past six years, shaving £1.2m off energy costs and saving the equivalent of the power needed to run 4,500 homes.

The scheme is financed by Private Finance Initiative and managed by Scottish and Southern Energy using specialist technology from Mayflower Control that provides an array of remote solutions including triggering individual lights to send an alert when in need of maintenance.  For the past two years, Hampshire County Council has been the fastest in the country at mending broken street lights.

As Mayflower puts it:

If you’re managing the performance of 147,000 individual lights as well as regulating their brightness, you need innovative technology and that’s exactly what we have developed for Hampshire”.

                Patrick Mitchell, Head, Mayflower Complete Lighting Control

It should be noted that Hamphire’s savings have been largely achieved with control of discharge lighting. The opportunity for savings with LEDs remains. Companies such as Osram and Lumileds( a joint venture between Philips and Agilent Technologies), continue to develop increasingly efficient LED lights further reductions in electricity consumption and carbon can be achieved. The use of LEDs combined with increasingly sophisticated remote control systems, are saving energy, saving money and smartening up our street lights.

[1] Highways Term Maintenance Association.  www.htma.info
[2] History of lighting
[3] Scottish Futures Trust.  Street Lighting Energy Efficiency.  November 2012.  www.scottishfuturestrust.org.uk
[4] Campaign to Protect Rural England.  Shedding Light.  July 2014.  www.cpre.org.uk
[5] Journal of Epidemiology and Community Health. Jech.bmj.com