LED Street Lighting Advantages!

[tom baker]

There has been much discussion lately about the merits of LED lighting. I was attended the IES Street and Area Lighting Conferences 8 times from 2002 to 2013, and watched as LED lighting was introduced and became accepted.
One advantage has not been discussed, that of less weight (less raw materials, packing materials and no hazardous waste).
So, I don't recall the person who objects, but here is a picture of a signal pole with a LED luminare at the top, the pole got hit, pole movement resulted in the luminaire being shot off the end of the pole and was hanging by its cable. A HPS cobra head with its weigh, would of come off, probably went across the street, hit a car.
This is 30 ft in the air, at a busy intersection. The LED is very light was easy to reinstall. I have installed may HPS 400 watt cobra head luminaires, its tough in a bucket by your self. Saturday when this was fixed it was pretty nice out, so went quick.

 

[Electric-Light]

LED street lights weigh less, because they use a transistorized switch mode ballast just like the RF driven VHO CFL. Induction street lights have struggled with long term durability not due to lamp but ballast failures. Solid state HID ballasts are used all the time by indoor growers. It's much easier to get them to regulate lamp operation better than CWA, weighs less and costs less. The real truth is that high frequency SMPS ballasts are substantially cheaper to make in China and ship them here which makes it that much more profitable for online retailers. High power passively cooled SMPS ballasts have terrible track record for RF interference and reliability. This is why they're not used for demanding applications and HIDs continue to use the conventional ballast despite the high cost.

What happened to the interest of domestically produced goods?

LED lighting probably has the highest Made in China contents of electrical goods. Made in China of Chinese made components from top to bottom and there is a significant China "IP" troll issues around LED. Have you seen how China is heavily invested into LEDs?
LED manufacturing is actually subsidized by none other than the Chinese government. http://www.ledinside.com/news/2016/...tal_rmb_12b_subsidies_from_chinese_government

The LED industry recycled the same theory that's been tried and pitching kelvin as LED technological advancements. Look in street light equivalence claims for LED lights from 5-7 year ago. The LED wattage needed match HID has been growing despite increasing LED efficacy.
The push for higher kelvin LEDs was an attempt to justify then extremely expensive and poor efficacy LEDs using scotopic enhancement multiplier to place LEDs into a favorable market position. Things that should not change are changing again right now, because those are the same smoke and mirrors recycled by the LED industry to position then costly LED lumens into competitive position with traditional lighting and they had to justify a very high wattage gap in order to make any type of ROI happen with the extremely expensive LEDs of the time that had inferior lm/W to HPS.

The higher kelvin LED as an attempt to reduce cost by lacking lumen output is severely criticized.

https://spectrum.ieee.org/green-tech/conservation/led-streetlights-are-giving-neighborhoods-the-blues
LED Light Pollution - Business Insider

Scotopic/mesopic amplification has been ongoing at least since the 1990s and it wasn't perceived too well. The idea to leverage scotopic amplification has been tried but LED industry dragged it back out again.
Lighting Research Center RPI 68-1996.pdf

Saving wattage by shaving lumen and using scotopic multiplier has been tried over and over.

4000K 80+ CRI full spectrum ceramic metal halide that drops right into HPS fixture has been available for a long time, yet they didn't get popular with street lights. I didn't think that somehow trying to copying that with LEDs would go well and it didn't. There were also induction VHO CFL 865 which weren't received anymore favorably than small businesses trying out 6500K CFL only to switch back.

We're still tolerating pure non-sense like the use of L70 to define lumen maintenance for LEDs. The LED industry has been rather quiet of the fact 30% depreciation is worse than F40T12/CW from 1980s did not have lamp lumen depreciation as bad as what is allowed for LEDs. LEDs are very much like historic mercury vapor lamp in that the lamp seldom burn out but continue to lose lumen.

The efficacy gain through LEDs don't look so amazing when lumen loss is accounted for. An LED lamp that terminates at 560 lumen in 11,000 hours (note: 800 lumens out of box) is not an equivalent to 60W 860 lumen lamp that lasts 1,000 hours and changed 10 times. They're implying fading to 560 lm is fine. Since incandescent lamps don't accumulate much fading before they fail, that LED lamp is an equivalent to a 600 lumen lamp.

 

[tw1156]

The higher kelvin LED as an attempt to reduce cost by lacking lumen output is severely criticized

I have worked on the lighting manufacturer side and on the public side of specifying LED luminaires and designs have always conformed to IES lighting requirements for designs; I had not heard of utilizing higher kelvin LED as an attempt to reduce cost, unless you observe it from the angle of higher kelvin LEDs are more efficacious. I have seen the IES lower lighting levels as they historically noted designing to average footcandles for designs; designing to averages and not minimum levels of light benefited HID sources but hurt LED sources as HID had high foot candle levels under the pole.

4000K 80+ CRI full spectrum ceramic metal halide that drops right into HPS fixture has been available for a long time, yet they didn't get popular with street lights. I didn't think that somehow trying to copying that with LEDs would go well and it didn't.

HPS lamps compared to Ceramic Metal Halide lamps are much more affordable (1/10th the cost typically) and you didn't really benefit much with the longer life (by maybe a few thousand hours) and the energy savings wasn't ground breaking (400W HPS versus 310W CMH for example).

I will say I agree with you very much on the L70 aspect; utilizing TM36 to calculate the average life of LEDs seems to extrapolate a lot of "lab" data and cap it for manufacturers at 6 times the testing of the source to allow for its rated life. From the installations I have observed though for the past 7 years, LED luminaires have held their own. When it comes to not having to go out and service a street light, taking a bucket truck, setting up temporary traffic control, having a warehouse to store materials and lamps, and all of the other jazz that came with HID during its hayday, I'd say LED technology is doing well, but once again, glare caused by high driver currents will be what hurts it as manufacturers try to reduce the number of LEDs and start to utilize chip on board technology.

 

[Electric-Light]

I have worked on the lighting manufacturer side and on the public side of specifying LED luminaires and designs have always conformed to IES lighting requirements for designs; I had not heard of utilizing higher kelvin LED as an attempt to reduce cost, unless you observe it from the angle of higher kelvin LEDs are more efficacious. I have seen the IES lower lighting levels as they historically noted designing to average footcandles for designs; designing to averages and not minimum levels of light benefited HID sources but hurt LED sources as HID had high foot candle levels under the pole.

I still hold some skepticism over the S/P game. I believe the idea of using higher kelvin light has been going around for a long time. At one time, some installations used RE80 6500K VHO CFL at drastically reduced light level, but it was just a phase which suggests it was not exactly successful. They greatly emphasized "induction technology" but the performance claims had nothing to do with induction. It was about 6500K phosphor.

HPS lamps compared to Ceramic Metal Halide lamps are much more affordable (1/10th the cost typically) and you didn't really benefit much with the longer life (by maybe a few thousand hours) and the energy savings wasn't ground breaking (400W HPS versus 310W CMH for example).

CMH is made very much like HPS with a different fill material as they both use ceramic arc tube which is the reason HPS cost more than QMH despite the production volume. I am not sure the specific lamps you were comparing, but the cost difference was not that much. The entire basis for those who promoted MH or CMH (which has lumen maintenance more in line with HPS) was the whole "white light" vs orange-amber light and mesopic vs photopic. But switching back and forth between MH and HPS is not a huge challenge but despite this, there wasn't a overwhelming public support to replace HPS with MH even though it most definitely provides S/P ratio amplification.

I will say I agree with you very much on the L70 aspect; utilizing TM36 to calculate the average life of LEDs seems to extrapolate a lot of "lab" data and cap it for manufacturers at 6 times the testing of the source to allow for its rated life. From the installations I have observed though for the past 7 years, LED luminaires have held their own. When it comes to not having to go out and service a street light, taking a bucket truck, setting up temporary traffic control, having a warehouse to store materials and lamps, and all of the other jazz that came with HID during its hayday, I'd say LED technology is doing well, but once again, glare caused by high driver currents will be what hurts it as manufacturers try to reduce the number of LEDs and start to utilize chip on board technology.

The light source of HPS is about the size of a golf pencil and metal halide lamps are available in double ended or small outer bulb configuration and can easily adopt the approach used by LEDs. HPS lights that that are high up enough to stay out of line of sight unless you intentionally look at it regularly do so. Street lights that are within the line of normal sight are pleasing to the eye because of the optics used. The lens on cobra heads are purposely designed to minimize fixture surface brightness. If LEDs were simply put behind these optics, you would have similar visual effects along with the need to increase lumens. Conversely, if you combine mirrors and lenses that allow HPS or MH arc tube to be visible, you can substantially reduce lumen output and focus fc level on the road surface at the expense of severe glare.