Energy Saving Road Lighting in Norway (2018) | Hacker News Reader

Energy Saving Road Lighting in Norway (2018)

dailyscandinavian.com

54 pointsCharlesW47 comments

The article claims that they save 2.1 MWh per week (109 MWh per year) with a payback period of 4.5 years in Norway. It doesn't say how much it costs, but Norwegian electricity prices are around 83 EUR/MWh, so we can estimate that the lighting system costs roughly EUR 40k (US$43k).

Wholesale grid prices in the US are around ~$252/MWh at peak, which means the payback period in the US is only 1.5 years give or take, which is not a bad investment.

https://www.eia.gov/electricity/monthly/update/wholesale-mar...

Lighting rarely is using peak rates.

Good point. If we use the non-peak rate of $50/MWh, then we're looking at a payback period of 7.9 years, which is not as appealing.

In which countries? Remember this is a global discussion forum.

Are there countries where electricity is more expensive at night?

In the US freeways are not illuminated except near cities.

The headlights of your car are expected to be able to illuminate road signs.

This leads to design differences with US vs European headlights, with the US headlights aimed higher.

The next time you see a European car with fancy advanced headlights and wonder why you can't have that in the US realize it's because in Europe they illuminate road signs.

>The five-mile stretch of energy-saving street lights saves 2,100 kWH per week, which would amount to approximately 21 hours of ironing, or four hours of watching TV on a plasma screen.

Am I missing something? Five mile stretch? 21 hours of ironing? What iron is that.

I think they did their math wrong. If we assume an iron operates at 1000 W (probably about right), then 21 hours of ironing is 21000 Wh, or 21 kWh. Someone probably got a little confused and ended up off by a couple orders of magnitude.

I wonder how applicable it is to the US - most of the roads I know of with light traffic are also not lit. Maybe in some suburban streets or something.

Forget energy saving, this is just as important for reducing light pollution.

Yes this is the really important part of this

I had no idea this was a thing until a recent trip.

For a small while I was certain I had become too tired and had started seeing things. Quite trippy seeing another car about a kilometer ahead igniting the lights as it drove.

I've noticed that hotel hallways in Norway worked the same way. While on a tour, I poked my head out of my room quite early to begin the day - it was pitch black but only for a moment. My motion clearly set off the detectors and the hallway fully lit up.

I kinda wish this was the norm in other countries for apartment buildings, hotels, etc.

The Novotel North Cambridge hotel in the UK had lights that come on when you approach in all guest corridors, as well as room lights that require a room-key-size card to be inserted into the main light switch (so they all switch off if you leave the room, along with HVAC going into away mode).

I've also seen a number of grocery stores adopt display lighting that turns on only when presence is detected.

The credit card sized thing is common in many hotels. Fortunately an expired train ticket is the same size, and usually do the trick.

The grocery store thing is getting more common in the US - a friend said it makes her want to dance like a Disney princess :)

I've been in apartment buildings state side that kinda have this, but there was always some light. Enough to see the exit at least. I think I'd be scared shitless if it was pitch black because of motion detector failure.

Many older stairwells in Europe (Italy/Spain/Portugal) are like this.

They're pitch dark, but you turn on the first switch which gives you enough light to reach the landing (and they are timed), and then you have to turn on another light, and so on. But if you don't get there quickly enough, it'll be pitch dark.

MY first guess is that US has regulations banning complete darkness.

The safe default in such a failure ought to be an ‘on’ state

This would never work in the USA, we need to see the fiends in the hallway sitting in the dark.

The frozen foods aisles at my local grocery store does this.

Energy-saving HTTP serving, too.

just in case https://archive.is/Uw6wK

I hope it would actually turn fully off instead of just to 20%. If we did this everywhere and regulate outdoor lighting severely, we may be able to see the starry night sky again just on the outskirts of cities.

In WA state we do have parts of the freeway that are not illuminated.

It’s obviously up to code but whenever I drive at night it feels super dangerous especially on a rainy day where visibility is low. This is unlike expressways in Chicago that are super well lit.

Light pollution is a thing, but when it comes to high velocity moving objects like cars more lighting contributes not only to safety but perception of safety.

It's much more efficient to have brighter vehicle headlamps and reflective signage and road surfacing. You drive as fast as your visibility allows for stopping distance. When the visibility is poor, the instinct is to travel slower and pay more attention, which contributes to safety. Perception of safety is often not correlated to safety at all. Roundabouts are much safer and often more efficient than traffic lights, but drivers tend to feel scared using them, resulting in reduced speeds and much less injuries.

> You drive as fast as your visibility allows for stopping distance.

This assumption does not hold true in many places, especially in the Seattle area. Highways here seem to be engineered for a presumption of competency that does not hold true (including the lack of sufficient lighting), especially when it rains. The crash rate reflects this.

Perception of safety is sometimes negatively correlated with safety, though. There's a level of highway engineering where you can make a road look like it needs more driver attention (curves, chicanes, worse lighting) while actually keeping fewer crashes and a comparable level of throughput.

Would you say not lighting a highway correlates with either though?

I thought most of the interstates are not illuminated unless you get close to major cities.

Just drive with lights on.

Correct. Once outside of the metro areas the highways are often unlit. It’s actually surprising to find parts that are (often interchanges, exits, near prisons, etc).

The US has a LOT of highway miles out in the middle on nowhere.

A lot of carbon could be saved if traffic lights include a camera and software that maximizes throughput.

I see an awful lot of lights that turn red just as a platoon of cars reaches it. And lights that sit there, red, when there's no cross traffic. And lights where one car comes up a side street, and the light turns red blocking 20 cars on the main artery.

I drove over few highways that had raised reflective markers installed with no other lighting. Worked exceptionally well and the experience was far better than any other road lighting. One of the problems with lighting is that it can be fatiguing after some time. Point sources of light create uneven illumination which are not the most comfortable. You are also exposed to the bright source from time to time which causes your eyes to adjust constantly. With reflective lighting you have none of these drawbacks. You're not surrounded by lights all the time, so you get a dark and soothing atmosphere. They are also down on the road, which allows you to follow the contour of the road very easily. The biggest benefit, they consume no power at all.

This is what’s so tiring about driving on two way streets. The vision fatigue.

> The five-mile stretch of energy-saving street lights saves 2,100 kWH per week, which would amount to approximately 21 hours of ironing, or four hours of watching TV on a plasma screen.

Irons are rated at around 1 kW (and that's not continuous for all irons I've used). 21 hours of ironing is therefore 21 kWh max, probably a whole lot less (1/10 doesn't sound wrong). Plasma TVs (depending on size) use a couple hundred W.

It kind of seems like the article author is confusing "." and ",", so they were perhaps thinking the street lights saved 2100 Wh (which definitely doesn't sound right on a per-week basis). (In some European countries they use , for the decimal separator.)

> (In some European countries they use , for the decimal separator.)

Yeah, its an article about Norway, by a Norwegian, in the Daily Scandinavian, an outlet whose name is a pretty big clue as to its focus, and of which the aforementioned Norwegian is editor-in-chief. What do you expect it to use for the decimal separator?

Well, they got it wrong...

Wow, cool, so all you need to do is wire these into your panopticon, and you've got citywide surveillance of anything and everything that moves.

Signed, a guy who's quite uncomfortable with IR detectors on urinals and toilets.

We have similar setup at tram/bus stations here in Zürich, Switzerland. When you sit still on the bench the lights will start to dim down and once one move they will brighten up again. A bit odd sometimes...

The toilets at my work do that, the light turns off if it detects no movement so I need to start waving my hands while I'm on the john and end up in the dark.

If the sensor is near the door it should be able to just count people coming in and out.

That "just" hides something that is so insanely hard to make work reliably in practice, any implementation of it is likely worse than a simple motion sensor... or a light switch.

If you’re in a cubicle with no smart sensor, there’s nothing to see your waves of despair.

Never underestimate the torch screen on a smart watch, just so long as the sleeve doesn’t slide down to cover it.

Plot twist: the bosses deliberately had it wired that way so that employees spend less time on bathroom breaks.

I wonder if there's any issue with disorienting pilots - having lights sliding along the ground could provide misleading visual cues. I know the flashing lights on tall objects are sync'd specifically to avoid any illusion of movement. Probably more of an issue in the US where there are a lot of low-currency private pilots flying night VFR.

It’s an old article (2018). At first I thought they had the wrong prime minister, then I realized it was written 5 years ago.

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