A high pressure sodium vapor lamp has an efficiency of around 150 lm/W. An LED has an efficiency of under 100 lm/W.
Where is the energy savings? If anything an LED uses more energy, not less.
Also, the referenced document shows LED lights as emitting 70 - 150 lm/W, so power consumption may be better than you think.
[1] http://www.grahlighting.eu/en/street-lighting-technology-com...
Source?
Allegedly, Cree has developed a white LED with up to 254 lm/W. [1]
[1] Cree Sets New Record for White LED Efficiency http://techon.nikkeibp.co.jp/english/NEWS_EN/20120423/214494...
It's poor form to ask for a source of something that would take you 15 seconds to google.
> Allegedly, Cree has developed a white LED with up to 254 lm/W
Interesting considering that the theoretical maximum is 251 lm/W - so I wonder which law of physics they violated to do that. (Most likely it's not actually white, but reddish.)
And this time I will give you a source since this is a tiny bit harder to google http://physics.ucsd.edu/~tmurphy/papers/lumens-per-watt.pdf
Light should be on but see no light and it's winter time? Turn on the heater.
Same situation in the summer? Send out a tech, the light's probably out.
The energy consumed by a 100-watt GLS incandescent bulb produces around 12% heat, 83% IR and only 5% visible light. In contrast, a typical LED might produce 15% visible light and 85% heat.
You can't always put a LED light in a enclosed fixture, as it might even overheat. It needs some air flow to cool it's heat sinks.
It could work for highway interchanges though.
Why is this listed as a benefit? A bug that is at the streetlight is a bug that is not at my house. Is there some problem with bugs congregating at streetlight that I'm selfishly ignorant of?
Insects could live without us. We couldn't live without the insects. My interest is entirely selfish. ;)
Of course, this is getting into much bigger issues than just streetlights...
Further reading: http://lighting.com/light-pollution-wildlife/
http://news.discovery.com/animals/zoo-animals/bugs-streetlig...
> People with homes closer to street lights may be at greater risk for exposure to certain insects, and even the diseases some of them could harbor. For example, another recent study showed that Triatoma dimidiate, an insect that can carry Chagas disease (an inflammatory, infectious illness), infested houses that were in closer proximity to street lighting, Davies said.
Our society is still really stupid about sleep.
"But in most cities around the country, the local electric distribution company provides overhead street lighting as a basic service at a flat monthly rate per light, which includes the light itself, maintenance, and electricity. Therein lies the rub—regulated utilities often have little incentive to invest in more efficient streetlights, which offer a reliable, consistent, and often lucrative revenue stream that comes at a time of day (or night) when demand is low."
If their getting a fixed rate, LED's would be quite profitable for them due to lower servicing costs, and lower power consumption - meaning for that fixed rate, they take in more income.
Beyond that, in many cities - running and maintaining the streetlights is included in the franchise rights to sell power in a given city - meaning to sell power, the power company had to install and pays for the lights.
In the UK the Roads Service ( NI ) or Highways Agency are responsible for the emplacement and maintenance of lighting. So they'd be quite grateful for any power saving, as the electricity distributors charge them for actual usage.
Another solution would be to eliminate most street lighting, but that's a rather touchy subject.
To add insult to injury they put CCTV cameras on every alternate lamp as well.
The only disadvantage I've spotted is that, with the old Sodium vapour lamps, it was easier to spot when a car was coming around a bend since the headlight colour was significantly different to the ambient streetlighting. I'll adapt.
Someone who doesn't know what a LED is surely won't understand that "clarification". Marketing mindset!
(Se also the Mad Men episode where they come up with the new slogan for Lucky Strike cigarettes)
In addition to the power savings, the old bulbs lasted an average of 72 hours between replacements, while the new ones have an estimated lifetime of 12 years, and replacing them is the 'hidden' cost that a lot of people wouldn't normally consider (and replacing bulbs mounted on a bridge is even worse than replacing street lights).
http://www1.nyc.gov/office-of-the-mayor/news/343-13/mayor-bl...
However I can see that it might well be disruptive for utility companies if those municipalities should decide to switch anyway(as per the article).
[1] http://www.manchestereveningnews.co.uk/news/greater-manchest...
http://www.htwk-leipzig.de/typo3temp/pics/5e8c7a9140.jpg
http://www.elektromobilitaet-verbindet.de/projekte/laternenp...