Street lights

positron

We are all constantly looking at cutting down our energy usage for economic and environmental reasons - which makes me wonder, what is the story with the street lights in Ireland?

I presume they are not halogen lamps, but sodium-vapor lamps perhaps? Are these energy efficient, or is there a better alternative coming in use here or elsewhere?

I think this is important because the street lights are left on all night throughout the year, and in winter months they are in use upwards of 18 hours a day. Considering the length of lit road network and housing estates, there should be a some money to be saved there by coming up with a cheaper lighting system.

PS: And may be even a smarter way to turn the lights on when someone needs them (rather than leaving it on all the time). How about sensors on lamp posts that will turn on all the street lights for a mile forward etc?

cnocbui

They are either high or low pressure sodium vapour, and yes they are very energy efficient, which is why people put up with the colour.

You can't turn them on and off on demand due to the very long warm up time (the sodium first as to be vapourised) so smart lighting is out.
There is no better alternative that I am aware of and nothing new on the horizon.

The latest technology I am aware of involves stimulating sulfur gas with microwaves. It is highly efficient but puts out such a vast amount of light it is only practicable for very large scale use. http://en.wikipedia.org/wiki/Sulfur_lamp

Put street lights on a timer and turn them off after 2am.

I remember as a kid living in a city where the street lights went off at 2am. It was brilliant. Got to clearly see comet kahoutek thanks to that practice.

positron

Thanks cnocbui.

Just googled on this, and found out that a number of cities are considering switching to LED, for example, Washington DC (see link below).

http://blog.mlive.com/michigan/2008/04/study_new_street_light_technol.html

Intelligent turn on/off would a really cool feature, and if sodium vapor lamps is no good at that, I suppose that's good enough reason to replace them with LEDs!

And yes, unpolluted sky to view the celestial wonders - that's another totally awesome reason why someone should look into this..!

ConsiderThis

cnocbui wrote: »

Put street lights on a timer and turn them off after 2am.

I remember as a kid living in a city where the street lights went off at 2am. It was brilliant. Got to clearly see comet kahoutek thanks to that practice.

Even if we turned off every second, or third, lamp at something like 2pm, there would be a considerable financial savnig to be made also. It's this kind of simple but effective thinking which puts governments to shame!

positron

http://blog.norway.com/2009/04/27/oslo-street-lighting-system-slashes-energy-use-with-echelon/

Oslo chose an intelligent street lighting system based on Echelon’s LONWORKS technology, an open, extensible architecture that lets control devices from multiple manufacturers interact with each other. The project—the first large-scale implementation of a LONWORKS based control network in a street lighting application— includes replacing older, inefficient mechanical ballasts in the city’s 55,000 streetlights with electronic ballasts from SELC Ireland Ltd. The ballasts communicate over existing power lines using Echelon’s power line technology. The first 6,500 ballasts have been installed; the rest will be installed over the next three years.