IET
Decrease font size
Increase font size
Topic Title: Reducing Street Light Energy Consumption
Topic Summary: Is it worth switching off some street lights late at night?
Created On: 04 February 2010 03:04 PM
Status: Read Only
Linear : Threading : Single : Branch
Search Topic Search Topic
Topic Tools Topic Tools
View similar topics View similar topics
View topic in raw text format. Print this topic.
 04 February 2010 03:04 PM
User is offline View Users Profile Print this message



jguest

Posts: 7
Joined: 05 October 2006

I was travelling to work the other evening and noticed on one particular road every other street light was off.
The general lighting levels were still pretty reasonable which got me thinking.

Why do the highways agencies not install cheap time switches to alternate street lamps in nominated areas. Then turn off the lamps between the hours of midnight and 5 or 6 am - not all of them.

The reduction in energy useage should more than exceed the installation costs of the timers, etc. And there is also the reduction in co2 emissions, etc.

Thoughts anyone?
 04 February 2010 03:32 PM
User is offline View Users Profile Print this message



westonpa

Posts: 1771
Joined: 10 October 2007

Originally posted by: jguest

I was travelling to work the other evening and noticed on one particular road every other street light was off.

Seems to suggest that schemes are already being tested and/or implemented.

Regards.
 04 February 2010 05:29 PM
User is offline View Users Profile Print this message



jguest

Posts: 7
Joined: 05 October 2006

You would think so but knowing our local council it is more likely to be a circuit failure
 04 February 2010 06:46 PM
User is offline View Users Profile Print this message



westonpa

Posts: 1771
Joined: 10 October 2007

Try searching Google and you will find many councils are testing schemes.

Regards.
 05 February 2010 07:05 AM
User is offline View Users Profile Print this message



normcall

Posts: 8111
Joined: 15 January 2005

It used to happen.
A man used to come and wind the clocks up to turn the gas on.
Then electric clocks were used, but power cuts made them unreliable.
Then PE cells solved that problem.
I could go on, but Buckinghamshire have introduced a cunning idea of actually turning of street lighting. They have erected signs saying that the street lighting wasn't working.
Apparently in about 5 years it will be a choice between Coronation Street and a cold beer or lights along the road.

-------------------------
Norman
 05 February 2010 09:17 AM
User is offline View Users Profile Print this message



westonpa

Posts: 1771
Joined: 10 October 2007

Originally posted by: normcall
Apparently in about 5 years it will be a choice between Coronation Street and a cold beer or lights along the road.


And the roads are now full of pot holes and the like and I think the councils are about 10 years behind on road repairs. All rather suprising when we consider how much council tax, road tax and duty on petrol/diesel has risen over the last 10 years.

Regards.
 05 February 2010 06:48 PM
User is offline View Users Profile Print this message



ArthurHall

Posts: 735
Joined: 25 July 2008

Alan
The Clyde tunnel had this system with extra lights at the exits and entrys. The lights were switched to suit how bright it was outside. The idea was that the light level was reduced slowly to let your eyes adjust to the light in the tunnel. Again at the exit your eyes were given a chance to adjust to the higher outside light level. I am not sure if the system was retained after the last time the tunnel was refurbished, I will check the next time I go through.
 05 February 2010 08:22 PM
User is offline View Users Profile Print this message



GJH

Posts: 496
Joined: 24 January 2008

Its a good idea but it would take a lot of time and money to introduce.
Most of the street lights are fed directly off the main supply cable and controlled via a photocell. The older lamps are controlled by timeclock and did/do have a setting where it comes on at dusk and off at midnight and then back on at 5am for the morning rush hour. This is only in a small percentage of the country if at all.
It would cost too much to employ an operative to drive round and reset the timeclocks every time there was a BST/GMT change and if the power failed, replacement timeclocks etc.
On my estate the council have trialed a system with low energy lamps fitted. They give off just as much light as the normal 70w SON or 35W SOX lamps and are controlled via a photocell. This could be the future of less power consumption.
The original cells were £70 each! and had an electronic radio signal in them that sent a signal to the council depot when the light had failed, this saves a night patrol being carried out.
I had a look the other day and normal photocells had been fitted so the trial couldnt have been succesful.
The normal cells are about £6.00 trade and is obviously a cheaper option.
 06 February 2010 09:49 AM
User is offline View Users Profile Print this message



GJH

Posts: 496
Joined: 24 January 2008

Sorry Alan, i dont understand?
 06 February 2010 06:06 PM
User is offline View Users Profile Print this message



alancapon

Posts: 5745
Joined: 27 December 2005

Interesting. We look after the street lighting in most of the towns and villages here, apart from Douglas, our capital. Each area (apart from Douglas) uses a "switch wire" for the public lighting. The switch wire is then turned on and off using a photocell and timeclock(s) at a central location, using repeat relays to introduce sufficient feeds to supply all the lights. The village I live in (for example) uses a photocell to turn the lights off in the morning, and on again in the evening. Three timeclocks are arranged to switch the lights (apart from the village centre) off at 1am, the village centre off at 3am and all lights back on at 6am. The other towns and villages we look after have a similar setup, generally being "dark" between 1am and 6am (using one or two timeclocks each). The lights can be energised using a bypass switch, which allows for day time fault-finding or a day time "drive round" looking for failed lights. The downside of our system is that a faulty "repeat relay" or loss of a feed can take out a significant number of lights. The timeclocks generally have a "clockwork backup" to take account of any supply failures, and we end up with relatively few timeclocks to alter for BST / GMT.

Regards,

Alan.

Edited: 06 February 2010 at 06:13 PM by alancapon
 06 February 2010 09:10 PM
User is offline View Users Profile Print this message



jcm256

Posts: 1839
Joined: 01 April 2006

I have not seen any of these LED street lights yet but apparently they have been used elsewhere from 2007 must be some fitted somewear in UK by now.

LED Street Lights solutions from Safety Power Ltd

LED street lights slow to shine in UK - 13/06/2007 - Electronics ...

Regards
jcm
 07 February 2010 07:05 AM
User is offline View Users Profile Print this message



normcall

Posts: 8111
Joined: 15 January 2005

Alan, that's the old '3 wire system'. We used to have a time switch or PE in the local sub and the 3rd wire controlled the lighting.
Ok while you had dedicated cables for street lighting. Now it's just tapped into nearest cable in urban unless new work when feeder pillars are installed for roundabouts etc.
Add in different contractors and cable records that were last updated in the 1960's, what do you expect?

-------------------------
Norman
 07 February 2010 09:52 AM
User is offline View Users Profile Print this message



alancapon

Posts: 5745
Joined: 27 December 2005

Originally posted by: normcall
Alan, that's the old '3 wire system'. We used to have a time switch or PE in the local sub and the 3rd wire controlled the lighting.

That is correct. A lot of our network is based on 5-core mains, with a reduced core for the streetlight switch wire. Now that 5-core is not available, we are using dedicated street light cables, but still keeping the same system. We believe it has many benefits still!

Regards,

Alan.
 08 February 2010 07:21 AM
User is offline View Users Profile Print this message



normcall

Posts: 8111
Joined: 15 January 2005

It would work when you have overall control, but here on the main land, it really is out of control with different contractors working in different places - often on annual contracts - what a mess!

-------------------------
Norman
 10 February 2010 05:21 PM
User is offline View Users Profile Print this message



obrennan

Posts: 2
Joined: 01 January 2005

The main difficulty with switching off every other street light is that you create a "strobe effect" to drives travelling down a street at night. That is the drivers eye is constantly re-adjusting from a higher to a lower light level which reduces the drivers ability to perceive / distinguish objects (like going from a fully lit room to a dark room).

The BS EN standard on street lighting specifies the required minimum lighting (luminance and / or illuminace) levels on a road. The minimum overall uniformity is 25% inside in estates, it is between 40% and 60% on traffic routes. If you turn off every other street light at say midnight you are actually likely to do more harm than good (you may be better switching off all the lights!).

The best way to save energy is to dim the lights at a pre-determined time (say midnight). This is particularly useful on traffic routes where overnight traffic levels (12pm to 5am) result in a lower lighting classification being applicable. Energy savings of 30% to 40% are achievable.

As with all energy saving ideas, one has to look at the whole life energy cost of a particular scheme (not just the headline figure), e.g. that's why hybrid cars are actually less efficient than many diesel engine cars that don't have 500 kg of battery being carried around that need replacing every three to five years!
Statistics

See Also:



FuseTalk Standard Edition v3.2 - © 1999-2014 FuseTalk Inc. All rights reserved.