LED streetlights in New Zealand

[RODALCO]

There are a couple of streets in Auckland where LED streetlights are trialled.

A few images are attached below, this was taken in Glen Eden

http://farm4.static.flickr.com/3565/3369713346_d56edae186.jpg?v=0

slimline design

http://farm4.static.flickr.com/3652/3368889875_6ce8ee779e.jpg?v=0

streetlight off

http://farm4.static.flickr.com/3476/3369709800_3b017f7fff.jpg?v=0

streetlight on

The colour looks ok, bluish white, but the beam is relatively narrow, hence darker zones between SL poles.
IMO more SL poles are required to get the same effect as with sodium HP.

 

[nzbazza]

Do you know who is running the trial and what model and specs of the LED streetlight?

 

[RODALCO]

Waitakere City Council

There appear to be some of these on the North Shore as well.

Don't know the specs but will try to find out

Regards, Raymond

 

[holiday light express]

The City of Ann Arbor changed a lot of their lights over last year. They light up far better than the old street lights! I think Relume made their lights for them.

 

[John_Galt]

It's good to see more people looking for better alternatives to high pressure sodium. I wonder what kind of output they have (probably in the few 1,00's range). Are those cold, neutral, or warm white LED's?
I've been trying to convince my local council that they should replace the streetlights in my town with LED ones. They have been unable to give me a monthly power bill, so I could show them how much they could save. Half our streetlights are out, anyway. (And have been since I moved here, about 5 years ago. I guess that's one way of saving money.) Cool tho.

 

[ponygt65]

SOLAR powered LED street lights would be good if used correctly. As stated above a one for one would most likely not be ideal. Unfortunately, they are quite expensive. That's why cities don't do that kind of thing. They have to budget for it, and that takes time to do and by the time they do it, prices could have gone up. It's a catch 22 with the way they ahve to do it in some respects.

I still think they should do it though. I think Street light LED's and NO businesses are allowed to keep they sign lit between 12 and 6 am, unless they are open or on Friday and saturdays. Could you imagine the amount of energy that would be saved then?

Too bad no one will go for it.

 

[holiday light express]

This tells all about the Ann Arbor project

http://www.a2gov.org/government/publicservices/systems_planning/energy/Documents/LED_Summary.pdf

 

[blasterman]

From the PDF.....

Wattages vary from 50 to 80 watts for fixtures that replace 250​

​

​

​

‐watt fixtures.​

Which makes me wonder how that's possible when LEDs don't have that significant factor of efficiency improvement over HPS/LPS illumination.

Which leads me to believe the fixtures they are replacing are either old or very poorly designed (?)

 

[LukeA]

From the PDF.....



Which makes me wonder how that's possible when LEDs don't have that significant factor of efficiency improvement over HPS/LPS illumination.

Which leads me to believe the fixtures they are replacing are either old or very poorly designed (?)

Na fixtures emit light in all directions. They lose light in the reflectors. LEDs don't. That accounts for some of the difference. Probably combined with the fact that the white light reflects better off of more surfaces better than Na-based light.

Even cold white has higher amounts of the different wavelengths than Na light, and so lower illuminances are needed to produce the same visual effects. For example, a blue car is distinguishable from a black one under a lower illuminance of white light than what would be necessary under LPS/HPS Na light.

In short, it takes a smaller amount of good light to equal a larger amount of crappy light.

 

[ponygt65]

From the PDF.....



Which makes me wonder how that's possible when LEDs don't have that significant factor of efficiency improvement over HPS/LPS illumination.

Which leads me to believe the fixtures they are replacing are either old or very poorly designed (?)

Basically to ellaborate on Luke'spoint below, they go off of photopic and scotopic lumens instead of 'traditional' lumens.

I do agree that they were replaced when the lamps were older. That's how ALOT of retrofitters get jobs. They go off of P/S lumens and shows that 'brightness' over aged HID's, which we all know isn't a 'true' comparison.

I think CRI and Kelvin should be considered, but not to the point where actual lumen ratings are completely ignored as every persons eye is different.

Na fixtures emit light in all directions. They lose light in the reflectors. LEDs don't. That accounts for some of the difference. Probably combined with the fact that the white light reflects better off of more surfaces better than Na-based light.

Even cold white has higher amounts of the different wavelengths than Na light, and so lower illuminances are needed to produce the same visual effects. For example, a blue car is distinguishable from a black one under a lower illuminance of white light than what would be necessary under LPS/HPS Na light.

In short, it takes a smaller amount of good light to equal a larger amount of crappy light.

 

[blasterman]

Na fixtures emit light in all directions. They lose light in the reflectors.

Especially if birds are building a nest in it. I mean, with LED you can't have a street light / bird condo now can we?

Friend of mine that used to work for the city told some very amusing stories about one time finding what looked like a birds nest in a cracked cobra-head only to find out it was a colony of bald faced hornets. This discovery coming after they "banged on it a few times" with a wrench to "scare the sparrows out" and ended being chased down their power lift by a swarm of enraged hornets instead. Fire dept eventually took care of the problem using a fire house - from a safe distance.

In short, it takes a smaller amount of good light to equal a larger amount of crappy light.

I'll be the first to buy a round of beer on that one my friend.

Still, getting serious for a moment (and putting aside our mutual annoyance of street lighting with a CRI in the single digits); Even though high CRI light sources are desireable over HPS for night illumination, how is this factored into the efficiency equation? At all?

LPS for instance is off the chart when it comes to rating craptacular light sources that should be restricted to the Walmart parking lot in Mordor , but it's very efficient because of it's narrow spectra.

I'd hazard a guess that LPS is likely more efficient than warm white LED.

Obviously it's easier to direct the light of power LEDs than a bulky HPS or metal halide tube. Still, reflector loss is 15-20% at the most. A bent sheet of polished aluminum just isn't that exotic.

Which is interesting because it mentions in the PDF about the public taking a first hand look and offering their subjective evaluation. This obviously takes into account the better aethestics of a higher CRI LED source.

Still, I'm uncomfortable about these claims of 2x-4x reductions in power consumption when the physics don't add up.

 

[2xTrinity]

Especially if birds are building a nest in it. I mean, with LED you can't have a street light / bird condo now can we?

Friend of mine that used to work for the city told some very amusing stories about one time finding what looked like a birds nest in a cracked cobra-head only to find out it was a colony of bald faced hornets. This discovery coming after they "banged on it a few times" with a wrench to "scare the sparrows out" and ended being chased down their power lift by a swarm of enraged hornets instead. Fire dept eventually took care of the problem using a fire house - from a safe distance.



I'll be the first to buy a round of beer on that one my friend.

Still, getting serious for a moment (and putting aside our mutual annoyance of street lighting with a CRI in the single digits); Even though high CRI light sources are desireable over HPS for night illumination, how is this factored into the efficiency equation? At all?

LPS for instance is off the chart when it comes to rating craptacular light sources that should be restricted to the Walmart parking lot in Mordor , but it's very efficient because of it's narrow spectra.

I'd hazard a guess that LPS is likely more efficient than warm white LED.

Obviously it's easier to direct the light of power LEDs than a bulky HPS or metal halide tube. Still, reflector loss is 15-20% at the most. A bent sheet of polished aluminum just isn't that exotic.

Which is interesting because it mentions in the PDF about the public taking a first hand look and offering their subjective evaluation. This obviously takes into account the better aethestics of a higher CRI LED source.

Still, I'm uncomfortable about these claims of 2x-4x reductions in power consumption when the physics don't add up.

There actually could be a 2-4x reduction, or even more, if they employed a motion detector control on the LED light. HID lights cannot "hot restrike", and generally take a few minutes to warm up, so they must remain on for 12 hours/day continuously. LEDs can switch off and on instantly with no detriment (in fact, quite the opposite -- running the LEDs at a reduced duty cycle will increase the lifespan). Or lights could be dynamically dimmed to run at any current necessarily relatively easily, as well (compared to HID where that is possible, but very difficult). If street lights were only ON when vehicles or pedestrians were actually present, a huge amount of electricity might be saved, and a massive chunk of light pollution could be eliminated. Many, mnay streetlights would only need to be on for a VERY low duty cycle between say 12-4am.

Same thing with using LED lights that more efficiently direct light into a narrower angle, rather than letting 2/3rds of the light fall into ditches, or into the sky -- as is the case with most of the LPS lights in my area...

Of course I'm not holding my breath on something like that actually happening...

 

[jtr1962]

Still, I'm uncomfortable about these claims of 2x-4x reductions in power consumption when the physics don't add up.

So was I until I did the calculations. HPS, which is what is used in most of the world, has an efficiency of around 110 lm/W to 125 lm/W, depending upon the type of lamp and size. However, that's for the lamp only, without factoring in ballast and fixture inefficiencies. HPS ballasts are at best 85% efficient, so this brings the figures above down to the 93.5 to 106.3 lm/W range. The real kicker is fixture efficiency. It's around 50% to 60% in the real world, depending upon design. A HPS lamp is relatively large compared to the fixture it's in. A good portion of the light ends up either in the sky, or where you don't want it. So now the system efficiency is down to anywhere from about 47 lm/W to best case perhaps 65 lm/W. And this is using the lumen figures for a brand new lamp. Figure that they degrade to about 70% initial brightness before burning out. This puts average efficiency figures in the 40 to 55 lm/W range. In short, reality sucks but there it is.

Now let's take an LED fixture. I'll assume 80 lm/W for the emitter even though ones as high as 100 lm/W are readily available (and 125 lm/W is possible by underdriving). For various reasons too off-topic for this thread, it's much easier to efficiently convert mains power into something suitable for driving LEDs than it is to do so for discharge lamps. I'll assume 90% ballast efficiency although we can fairly easily exceed 95%. As for the fixture's optical efficiency, again I'll use 90% although 95% with good TIR optics, or 100% with no optics at all (with a properly designed LED package) is possible. That gives us a system efficiency of 65 lm/W, on par with the best HPS fixtures. Accounting for lumen depreciation (70% end of life, 85% average) gives us 55 lm/W, again on par with the best HPS lamps. However, note that I didn't stretch the envelope by using the best LEDs or ballast or optics available. Had I done a best case analysis (underdriven top binned emitters, the best ballasts and optics) then the average lifetime system efficiency would be around 110 lm/W, twice the best case HPS value.

Just going by raw output then we can see that an LED fixture is anywhere from 1 to 2 times as efficient as best case HPS. However, this doesn't account for the more favorable spectra. HPS spectra are really bad for lighting. It takes roughly 2 lumens of HPS light to give the same apparent brightness as 1 lumen of LED light. Accounting for this, LED ends up anywhere from 2 to 4 times as efficient as HPS.

Like I said earlier, I didn't believe the claims either until I ran the numbers.

I'd hazard a guess that LPS is likely more efficient than warm white LED.

You may be right here taking into account all of the above factors but LPS is rarely used for streetlighting in most of the world. And warm-white LEDs aren't a particularly good choice for streetlighting either (they're best suited to interior mood lighting for those who are into that sort of thing). Besides their poorer efficiency relative to cool whites, their spectra isn't as favorable as cool-whites for the same reasons HPS or LPS aren't. Aesthetically it's a horrible choice as well since it doesn't blend in well with moonlight or starlight. And from a safety standpoint any light source heavy in yellows (sodium lights are particularly bad in this regard) kills your peripheral vision (obviously very bad for driving).

 

[shortstack]

up here in Anchorage, ak is retro fitting 16k streetlights to led from HPS, although ours are 120W (HPS). they have used a few different styles, some work real well for replacing them and some really suck, just depending on how the "angle" and put the leds.

 

[holiday light express]

Being one who has actually seen these in action (and next to the lights they replaced) the LED's are far better looking light, and give off more light onto the street. You have to remember that the LED is going to put all the light down on the street where you want it, not up in the air which causes light polution. So all that really matters is that the LED fixtures put out the same (or in this case more) light on the street and use less electricity.

Here's some oics and a video..

http://blog.mlive.com/judy_mcgovern/2009/01/ann_arbor_led_show_goes_on.html

 

[blasterman]

I have too many points to bring up / contest right now, but my biggest one is:

... *if* the LED street lamps here have such a significant efficiency improvement over HPS (2x-4x as claimed above), then we'd be seeing HID fixtures being ripped off the ceiling of every commercial/private warehouse, factory, mall parking lot, etc., on the planet because the same engineering factors apply.

As it is, the public municipalities buying this technology are the same lunatics (at least in the states) that have absurd zoning ordinances against wind turbines, but want to raise my property taxes while my house plummets in value :scowl: rant / off

I can see some specific advantages for environmental lighting with LED over HPS...main one being variable illumination levels and higher CRI. Some of the others though reguire a near Hollywood suspension of disbelief. This being; 100% efficiency for LED drivers, 100% illumination level for LEDs over their entire lifespan, kids and vandals never throwing rocks at LED fixtures, optics and reflectors in LEDs reflectors being 100% efficient, LED light not being prone to atmospheric scatter, 120 degree lambertian radiating pattern of LEDs magically avoiding ditches and other locations, etc

 

[shortstack]

you have to remember not everyone knows about this led lighting, at least not to this high of lumens that they can replace. plus the initial sticker shock is probably why most places haven't dont it yet

 

[holiday light express]

I have too many points to bring up / contest right now, but my biggest one is:

... *if* the LED street lamps here have such a significant efficiency improvement over HPS (2x-4x as claimed above), then we'd be seeing HID fixtures being ripped off the ceiling of every commercial/private warehouse, factory, mall parking lot, etc., on the planet because the same engineering factors apply. It's all about people not knowing about the LED technology, and people being short sighted..ie it costs them more now so it's bad.

As it is, the public municipalities buying this technology are the same lunatics (at least in the states) that have absurd zoning ordinances against wind turbines, but want to raise my property taxes while my house plummets in value :scowl: rant / off Hmmm. My taxes went down this year because of declining home values.. This is a whole different issue not related to LED lighting though..

I can see some specific advantages for environmental lighting with LED over HPS...main one being variable illumination levels and higher CRI. Some of the others though reguire a near Hollywood suspension of disbelief. This being; 100% efficiency for LED drivers, 100% illumination level for LEDs over their entire lifespan, kids and vandals never throwing rocks at LED fixtures, optics and reflectors in LEDs reflectors being 100% efficient, LED light not being prone to atmospheric scatter, 120 degree lambertian radiating pattern of LEDs magically avoiding ditches and other locations, etc

It's funny you say these things... they all also apply to any other kind of lighting. What ever the lighting application is, it needs to be designed for it's intended use.

 

[RODALCO]

The biggest issue with the LED steetlihts are the costs of putting them in.

Also more poles are required to get the desired lighting level at the street.

HI - pressure sodium is still the one to go for cost wise and reliability wise.

As LED technology improves, no doubt that more LED streetlights will appear in cities around the globe.

 

[LukeA]

The biggest issue with the LED steetlihts are the costs of putting them in.

Also more poles are required to get the desired lighting level at the street.

HI - pressure sodium is still the one to go for cost wise and reliability wise.

I was just at an architectural LED lighting show yesterday where there was a booth from Visionaire Lighting, a company that sells both HID and LED streetlights, had a 75W LED model that the rep said could replace one of the company's 175W HID fixtures. That 75W replacing 175W seemed to be the theme among the other LED streetlight manufacturers as well.

The City of Pittsburgh is looking at replacing its HPS streetlights with LEDs. The primary reason cited is low lifecycle cost. The LED fixtures use less power and are supposed to last ten years before needing replacement, whereas the current HPS fixtures are replaced every two years. The move is supposed to save the City $15 million per year.

That sounds to me like LED streetlights are both cheaper over their lifecycle and more reliable than HPS sodium lights.