CMU School of Drama


Sunday, September 07, 2008

New York City to Test LED Streetlights

PLSN: "There are some 300,000 streetlights in New York’s five boroughs, most using 150-watt high-pressure sodium lamps to illuminate the city that doesn’t sleep. But the New York City Department of Design and Construction (DDC) has been waking up to the fact that LED alternatives can produce just as much light with less energy."

9 comments:

Aaron S said...

I have to say that I'm honestly surprised that it took this long for LED streetlights to be developed. A large amount of architectural lighting has been in LEDs for several years now, and municipalities jumped on the band wagon installing LED traffic signals. Why did it take this long to develop LED streetlights? The real design challenge is can they make a retrofit kit to minimize the cost and amount of labor needed to change the current sodium lamps, that will hopefully not require changing the actual pole.

Anonymous said...

I am also like aaron surprised that they have not yet developed these however I wonder if there are LED streetlights in other cities and states. I'm sure that it has been contemplated by other cities. I'm sure that OVI will copyright those and they will become popular around the country. I'm surprised though that the wattage is reduced by only twenty to thirty percent it seems like they could do better in that area.

Ethan Weil said...

It's worth considering that there was far less incentive for streetlights to become LED than other lights we've seen being replaced. Architectural lighting has been changing largely because previous options were very inefficient. This is because choices for such lighting were sensitive to color rendering. In point of fact though, lumen-per-watt Sodium Vapor Lamps (traditional streetlights) are more efficient than LEDs. (150 vs 100 roughly. Reference http://en.wikipedia.org/wiki/Luminous_efficacy#Examples_2 (sourced))
Certainly, there are some advantages to LED's (primarily the color rendering may be preferable - fewer lumens acceptable, toxicity, and life span) but it certainly isn't a no-brainer as the article makes it sound. LED's are very cool for many applications, but I think there's some overzealousness in putting them in places they may not be better.

There is similar risk with Compact-Florescent Lamps, which Rod Elliot has documented at http://sound.westhost.com/articles/incandescent.htm Again, they are very cool, but only in fitting applications. It seems like often the public policy bandwagon overlooks the actual facts. See: biodiesel.

Anonymous said...

There's more than just a few reasons to switch to LED streetlamps, don't diminish them. In large metropolitan areas (and especially California who suffers from brownouts and a constant energy crisis), the energy savings alone are worth it. Lots of labor will be saved by longer time between replacing lamps. Weight might also be diminished, reducing the amount of materials and damage materials used to support the light can cause.

They're much, much, much more environmentally friendly as well (from a "how we make power" standpoint, manufacturing, and waste product standpoint).

I wonder what the initial cost is to make the changeover per fixture..

Ethan Weil said...

Just to follow up a few other relevant numbers/facts. Again, these may be a better option, but it's not a clear-cut choice. Low pressure sodium-vapor has an average lifespan of 18k Hours. LED's last on average 35-50k hours. This is only around twice the life time. Sodium vapor lamps retain nearly all of their luminosity until they die, whereas LED's slowly, continuously dim. LED's are less heat-tolerant. Also, their much higher quantity of blue spectrum contributes more to light pollution in the atmosphere and neighborhoods. This may bother people living nearby. Just more trade-offs, there is not magic technology, just engineering choices. It's not clear that there would be either energy or maintenance saving. Facts are sparse on the article.

MBerger said...

Even taking into account the cost of installation and cost of the LED's themselves, I cannot understand why it has taken so long for this to be developed. Putting aside the cost issue, the fact that other cities and towns have not explored this issue surprises me. Perhaps this is something that CMU should look at installing on our campus.

David Beller said...

As we now live in a world where the need to sustain energy has come into focus, it is inevitable that changes like this be made. And based on the earlier posts... and recent studies, the cost to replace them is far less than the savings that would come from them. However, this is only true when the replacements would provide the same kind of service as the previous set up. Safety of the people cannot be given up to save anything.

AndrewLeitch said...

This is excellent news for New York, and the rest of the world, frankly. I'm also surprised it took as long as it did to create this technology but I'm glad it's finally come to be. The only concerns I would have with this operation is how changing these street lamps is going to affect the surrounding areas, traffic, and how much money this will be coming out of tax-payer's pockets. Although, for a little extra security and assurance that the street lights might actually work, I'm sure that's something many would be willing to spare a few dollars for. I know back home, there are miles of interstates and city street lamps which are never on, which is extremely dangerous at night and in bad weather.

Anonymous said...

Its time and happy to see it finally happening. Like some have already pointed out, I agree with the sustainability aspect in that if we can start focusing on the load and less on the source we can then produce more efficient systems that use less of the source, allowing for more diverse applications to come forth. In other words, more lighting from the sources we got to work with. Not just LED's though. More efficient Traffic control, heating for buildings both residencial and commercial, etc. helps us all in the end. Specially when you look at the electric bill for all those street lamps. Yikes.