Study: New LED street light technology could save energy, money

[philb]

Study: New street light technology could save energy, money
WASHINGTON (The Associated Press) - Apr 7 - By SARAH KARUSH Associated Press Writer

The nation's roads are a major source of greenhouse gases - but it's not just from the cars and trucks traveling on them. The lamps that light the way for those vehicles gobble up their share of energy, too.
By switching to a more efficient lighting for their roads, the 10 largest metropolitan areas could reduce annual carbon dioxide emissions by 1.2 million metric tons - the equivalent of taking 212,000 vehicles off the road - and save $90 million a year, according to a study released in March.

"Even if there wasn't the thought of global warming, this would make sense because it saves electricity, it saves taxpayer dollars," said Robert Grow, the study's author and government relations director of the Greater Washington Board of Trade. "It's really a no-brainer."

Grow wrote the report as part of a fellowship on sustainable growth funded by the Ford Foundation through the American Chamber of Commerce Executives. He focused on two strategies. One would be to simply change the type of lamps used to electricity-sipping light-emitting diodes, or LEDs. The other would be to create a centrally controlled street-light network that allows managers to adjust brightness based on environmental conditions and to quickly pinpoint malfunctioning lights - including ones that stay on in broad daylight.
Grow said he was surprised to learn that more hasn't been done already to improve street light efficiency around the country.
Perhaps the biggest effort is in Ann Arbor, Mich. The city announced in October that it would convert all its downtown street lights - some 1,400 - to LED lights, an effort estimated to cut electricity use in half. The Ann Arbor lights are manufactured by Durham, N.C.-based Cree Inc.; other manufacturers promise similar savings.

LED traffic lights have become common in much of the country, but LEDs that produce white light, instead of red or green, use newer technology. Ram Sarma, street light coordinator for Virginia's Arlington County, said LED street lights have only now been around long enough for local decision-makers to have data about actual costs and potential savings.
Arlington, which has committed itself to reducing greenhouse gases produced by the county government by 10 percent from 2000 to 2012, is in the process of installing five LED street lights. The county wants to gather feedback from drivers on the quality of the light they produce before it embarks on a wholesale replacement project.

The high pressure sodium lamps that the county now uses are about a decade old. They are about 25 percent to 30 percent more efficient than the mercury vapor lamps they replaced, Sarma said.
Besides LEDs, Grow looked at the centrally managed street light network being implemented in the city of Oslo, Norway. The system feeds data into a control center that keeps track of lights that need to be fixed and automatically dims street lights based on the season, local weather and traffic density. Street lights at dawn, for example, don't have to be at full power to still do their job, said Julia O'Shaughnessy, a spokeswoman for San Jose, Calif.-based Echelon Corp., which owns the technology being used in Oslo.
Sarma said he had heard about that technology but that the capital costs were too high and potential savings not great enough for Arlington to try it.

Grow estimated it would cost nearly $70 million to install such a system throughout the entire Washington region and would take about seven years to pay for itself in energy and maintenance savings.
Based on Oslo's experience and the estimates of LED streetlight manufacturers, Grow's analysis assumed a 50 percent reduction in electricity usage for any kind of street light improvement. He calculated the Washington region alone could save $6 million a year on electricity and reduce carbon dioxide emissions by nearly 78,000 metric tons.
Grow then extrapolated his basic assumptions to the 10 largest metropolitan areas. Besides Washington, they include New York, Los Angeles, Chicago, Dallas, Philadelphia, Houston, Miami, Atlanta and Detroit.
Maryland State Highway Administrator Neil Pedersen said his office was reviewing Grow's report and that it would seriously consider efficiency improvements to the lights on the roads it operates.
"There are capital costs associated with it that we need to understand," he cautioned. "There's still questions about what the longevity is of some of these lights."

[gateley]

1. Boy, the network in Oslo sounds impressive!

If we'd been studying how other countries approach many issues, health care, public transportation, etc., we'd be further along than we are today.

VERY interesting article -- thanks. Recommend!

[elocs]

2. Amazingly, some people where they have LED street lights bitch that they don't provide enough light,

that it is not diffuse enough. I heard one man complain to the mayor that the lights did not light up his house and the mayor's response was that it was not the city's job to light up his house. Good one.

[IowaGuy]

4. The LED lights are just the bulb...

they are only one facet of a lighting system. The lens in the fixture and the housing determine the focus of light dispersion and most likely affected how light was dispersed or not dispersed to that persons house. The nature of LED's would allow a very focused lens which in actuality would create a higher intensity\level of lumen's on the road surface compared to surrounding areas. This would help increase safety levels for driving. LED's also have a more natural spectrum of light coverage (slightly more blue than natural). HPS (High Pressure Sodiums) tend to cast a rather ghastly yellow glow on things.

[CRF450]

6. I dont see the point in yard lights

Especially my dad! He hates the fact that so many people here in the sticks have yard lights, and that makes it hard to see the stars in the night sky, not to mention, a neighbor directly accross the road of his house has one of those stupid decorative light house's that lights up the whole area by about 200ft in around it! The last major hurricane we had cut out the electric for a couple days, the night sky was BEAUTIFUL!! It was so cool to be able see a shit load of stars instead of 5 of here, and 8 their, one bright star their, and Jupitor in the middle. I can understand the need for them in a city neighborhood with high crime, but out the country, I think its just a feel good thing for the paranoids out their.

[elocs]

7. I believe that it was somewhere in Michigan where I heard about the LED streetlights

which were more directional rather than diffuse. The upside was that there was far less light pollution and so the night sky was easier to see.

[CRF450]

10. Yet many will complain about that like mentioned in a earlier post.

[Dont_Bogart_the_Pretzel]

15. I know what you mean, I remember about ten years ago there was

a law put in place (I think), I like the stars too.
Now since bushcrappingup the country, the super bright lights are on. :mad: some are so bright I'm sure we could turn off our headlights in that neighborhood.

[skids]

3. Trying to figure out lighting efficiency can be pretty mindboggling...

...but at the color temperatures for http://en.wikipedia.org/wiki/Scotopic_vision">Scotopic Vision LEDs may already be there efficiency-wise.

In the meantime if any DUer sees any streetlights that have not converted at least their red bulbs to LEDs, they should be getting on their town selectboard's case about it. That's a no-brainer. (Not much need to bother with the yellow bulbs.)

[diane in sf]

5. Pays for itself in 7 years, around 15% annual return on investment...

[Pawel K]

8. I'm once again skeptical

a lot of people seem to think LEDs are the savior. They maybe in the future, but I can not imagine how many individual LEDs you would have to put in one street lamp for it to provide enough light.

[DCKit]

9. Does it really matter "how many?"

At 5-10 mm across, it's not as if they take up a whole lot of space and automated manufacturing along with mass production would further lower the cost. Additionally, they are rated to last 100K hours, or 22.83 years, if left on for 12 hours a day AND they are >90% efficient, where standard, incandescent bulbs are only 5% efficient (I don't have the numbers on HP lamps handy, but don't think they're more then 45% efficient). The remainder is lost as heat - good for an Easy Bake Oven, but not so much when the AC is running.

The only downside is the initial cost, but with utilities around the country threatening 100% rate increases, you can cut the ROI in half.

We distributed $1,665 worth of CFLs to our apartment complex last winter, against some pretty hefty opposition - "it won't work", "they're too expensive", "it's too difficult", "they won't save us any money" and "we don't want to get into the light-bulb business". I believe, due to an ongoing education campaign, at least as many were purchased and installed independently. After five months, our $1,665 investment had yielded a return on investment of $20K on our electric bills in addition to the estimated $15K/year savings from CFLs installed in the public areas.

Yeah, I'd like to see a single answer to all our problems, but until we find the Holy Grail, we'll have to work with what we have available.

[Pawel K]

11. It does matter

as you said the initial cost is going to be huge.

And I have a really hard time believing you can efficiently fit that many LEDs in to a fixture that will provide the amount of light that you need to light up a street.

The 100K hours figure is also fairly misleading. Sure, after 100,000 hours they might still work but the light output will be a fraction of what it was when originally installed.

Don't get me wrong, I'm not knocking LEDs, I think they have great potential in the future, but they aren't there quite yet. Remember, it took 60 years since the first red LED to get to where they are today. I think it will take at least another 20 years for LEDs to compete with conventional light bulbs and much longer than that to compete with HID lights used in street lighting.

You are absolutely right, we have to use what we have. So might as well come up with effective, not feel good solutions.

Take the money that this would require and invest in some nuclear power plants. That will eliminate way more CO2 from our air than this perticular idea.

[DCKit]

12. The point is to spend the money in this way to prevent having to build the Nnew-cue-lur plants. n/t

[Pawel K]

13. The point I am making is that you will br pissing away that money down the drain

when spending it on nuclear power plants would be much more beneficial to this planet and our kids future.

I really don't understand why so many on the left are so opposed to nuclear energy, it is the only real solution we have to this global warming crisis right now. It is an expensive solution but if you guys are ok spending all that money on development of these led fixtures that will not be able to be implemented with the current technology then paying for something that actually works should be a no brainer.

[DCKit]

14. My Mom lives comfortably in a 100%, off-the-grid solar house...

and she's not exactly conservation minded. You're not going to convince me that we NEED Nnew-cue-lur anything or that money spent on efficiency and conservation are, or ever will be, wasted.

Americans are energy hogs, we shit where we eat and our need for instant gratification is pathological. Nuclear power can't cure those ills.

[Pawel K]

19. You just mentioned another great application for LEDs

lighting up a house running off solar panels is a great and efficient use for them. Your house will not be nearly as bright as a home using conventional lighting but it will be bright enough for most activities. But you didn't mention your mom uses LEDs for her solar home, why not? The simple answer is they are not bright enough. And if leds can not compete with 60 watt incandescent light bulbs they sure as hell will not be able to compete with 1000 watt hid bulbs that are used in street lighting. There is no reason for you to be so hostile about this, I am simply stating facts.

The other fact I mentioned is that the only real solution we have right now is to build nuclear power plants. It's an expensive solution but it is a solution that works. You want americans to stop wasting energy? The same americans that voted Bush in to office twice? The same americans that forget about what is going on every time Paris Hilton is mentioned? Good luck on that, I'll stick to real world solutions. You guys can continue to complain about nuclear power when in my opinion I don't think you have any understanding behind those complaints. You see nuclear weapons as evil so clearly nuclear power must be evil too. If that's not it then I would love to hear your explaination as to why you would support pissing away money trying to install LEDs in street lights, something that would not work for another 20-30 years, but don't want to use that money for nuclear power which we can safely and efficiently build today.

[diane in sf]

17. It's cheaper to conserve energy than build any power plant and nukes are more

expensive than any other kind of power plant--they are a massive waste of scarce dollars and resources.

[kristopher]

16. Is it the actual lighting or is it lack of standardized tests for comparison?

I thought there was some problem related to no statistical support for LEDs because of a lack of standardized tests. I don't know much about the topic and would be interested in hearing more if you are up to speed.

Added on edit. Anecdotally, I've switched all my flashlights to LED. I couldn't be happier with their performance both in the area of power consumption and light delivered.

[Pawel K]

18. I don't know of any testing issues

lumens (the amount of light emitted) are always measured the same way wether they are being put out by a light bulb or an led.

You mentioned the flashlight example. LEDs are great for low power flashlights. They can run for years off a single AA battery. The problem is when you need a high intensity flashlight like the ones police use, LEDs are no where near the point where they could replace these. Sandia national labs did a great study on this that I had on my computer a while back and now I can't seem to find, they pretty much concluded that LEDs will eventually over take traditional incandescent light bulbs but that will not happen until sometime in the 2020s. When I get some more time I'll try to locate this study again, hopefully I can find it.

So when you think of LEDs think of them as being able to replace low intensity lighting with the present technology. They are awesome for street lights, awesome for small flashlights, awesome for accent lighting, stage and special effects lighting, etc, etc, etc. But before they get to the point where they can compete with incandescent light bulbs it will still take many years and it will take even longer for them to be able to replace HID lights such as the ones used in street lights.