UK To Dim Highway Lights To Save Money 348
Hugh Pickens writes "The Telegraph reports that street lights on thousands of miles of major roads in England will be dimmed during quiet periods to save money and reduce carbon emissions. The Highways Agency has already turned off the lights on more than 80 miles of the motorway network and will soon begin a survey of where this can be done on the 2,500 miles of A roads it controls. Nigel Parry, of the Institution of Lighting Professionals, says that technology enabled lights can be controlled individually and remotely. 'The idea is that when traffic is busy, such as during the morning and evening rush hour, you have them at their brightest. When the traffic disappears you can dim them. You can maintain safety and use half as much energy.'"
EU Ratification (Score:5, Informative)
The biggest problem is that LED (CREE etc) based streetlights have not yet been ratified by the EU and so cannot be used on public highways in the UK. If they do become ratified then there will be huge power savings. In China, they have whole motorways lit up using this technology. Not only do they burn less power, but the lantern lifetime is much longer than the standard sodium units that have a warranty lifespan of 3 to 5 years.
One of the problems about dimming lanterns is that the lamp post spacing is all based around the lamps at a certain luminenscence and so dimming may create dark zones, or over bright zones. So some careful analysis will be needed about how the lamps dim and whether they dim uniformly or not.
Re:Electricity consumption -- where does it go? (Score:5, Informative)
The same place all the other excess energy goes into - methods to try and store it and use it at slightly less efficiency later in the day.
The usual example is to pump water back up a reservoir that's being used for electricity generation. So when it falls down again tomorrow, you can get useful energy from it again at the right time and only lose a percentage of the energy to keep pumping it back up there until you need it.
Still doesn't mean it's efficient but the thing about electricity planning is that they KNOW when things are going to ramp up or slow down (even down to the timing of the adverts in the middle of big football matches!) and if they know, they can do their best to compensate.
More likely, if the motorways are switched off on a regular basis, they will power down a more flexible station during those times because they know they won't have to supply as high a peak. You can't "turn off" nuclear easily, but the infrastructure isn't all nuclear. You could easily keep them going all the time to supply the "base" current and deal with peaks and spikes (like the motorway lights being on) with other means and get to shut down OTHER types of station that you wouldn't normally be able to because of the demand required.
Re:Highway lights??? (Score:5, Informative)
Belgium (notorious for lighting every square meter of higway, it looks like you're driving in broad daylight) decided to turn of every other light a couple of years ago. After the number of accidents rose some 25% they quickly turned the lights back on!
Sorry, but that's definitely no longer correct.
They shut off most of it last year. Afaik it's still shut off and the reports on the effects ranged between "no noticable effect on the accidents" and "slight decrease". The light increased visibility, but the feeling of safety seemed to lead to more speeding accidents and reckless driving.
Re:I might just be a luddite, but (Score:5, Informative)
It benefits pedestrians much more than drivers, but the lights make it easier for drivers to see where they're going too. Without street lights, the area outside of where your headlights land will be dark if there's a moon, or a pitch-black void if it's a moonless night, vs. with street lights where the whole road is lit up.
Re:EU Ratification (Score:5, Informative)
The biggest problem is that LED (CREE etc) based streetlights have not yet been ratified by the EU and so cannot be used on public highways in the UK. If they do become ratified then there will be huge power savings. In China, they have whole motorways lit up using this technology. Not only do they burn less power, but the lantern lifetime is much longer than the standard sodium units that have a warranty lifespan of 3 to 5 years.
Actually, the power saving for road lighting are negligible at best, or negative at worst. Low pressure sodium lamps currently in use produce up to 200 lm/W, compared to 100 lm/W for the better white LEDs around. There's not much that can compete with LPS for pure lighting efficiency, partly because the light emitted is near the maximum sensitivity of the human eye. Of course, LPS lamps produce monochromatic light which means they're not so popular for lighting urban/pedestrian areas, as people feel safer in a more "natural" light where they can see colours. But for roads alone, there's no need to see colours. Also, LPS is the least objectionable form of light pollution to astronomers, as being monochromatic it's easy to filter out (and there's not a lot of glowing sodium in space, so you're not blocking out anything of interest).
LED lights last longer if dimmed (Score:4, Informative)
Re:I might just be a luddite, but (Score:5, Informative)
Re:Electricity consumption -- where does it go? (Score:4, Informative)
You are incorrect. Nuclear power can load follow perfectly fine. The reason why they don't is because the cost of nuclear power is almost entirely fixed in personnel and equipment. The fuel is practically free (and with fixed schedule refueling outages, whatever you don't use goes to waste anyway). Therefore running at anything besides full power 24x7 is a economically inefficient. In contrast with say, natural gas turbines, where nearly all of the cost is fuel so you only use those to make up the difference in demand.
Night driving and special skills (Score:5, Informative)
In Montana, when during a short and unusual period of rationality we had somewhat unlimited daytime driving speeds [hwysafety.com], nighttime driving was still constrained to relatively low speeds because there is no safe driving regime that includes over-driving one's headlights. And while during the day it was kind of difficult to get a ticket when driving reasonably, at night, they could nearly hang you at the side of the road if you stepped out of line. IMHO, that was driving heaven. Accidents declined below Montana's previous levels, and other than gas milage, the side effects were pretty much uniformly positive.
Personally, we (my family) bought a relatively high-powered sports car capable of long-term high speed runs, and intentionally focused on traveling during the day, as one got to the destination faster, the driving was a lot more fun, concentration was better as more things happen faster, and said concentration, easier or not, didn't have to be maintained for as long a period.
As an aside: Daytime driving is safer here because the animals generally keep their heads down or they get shot off by our not very lovable rednecks. Often heard here: "Wanna go bust some 'dawgs?" This is a euphemism for going out and "popping" prairie dogs, and anything else that might show its eyes or ears, with a high powered rifle. This is about as popular as drinking. and often the behaviors are combined. Anyway, it leads directly to a very cautious daytime wild animal population.
Alas, the feds applied significant pressure by threatening to withdraw highway funds, our state legislators invented nonsensical justifications to accommodate the idiot feds without exactly looking like they were accommodating them, we lost our driving paradise, accident rates went right back up, and there you have it.