Shed a little light

At the end of the year, Arlington began a town-wide upgrade of street lights, converting from high-pressure sodium lamps to LEDs. The first area to be converted is right here in East Arlington.

New LED lamp (top foreground) versus old sodium.

The LEDs are more efficient and durable than the older sodium lamps and the Town expects to cut its annual street-lighting costs by from $115,000 (in one estimate) to $150,000 (in another).

Most of the funding for this round of upgrades is from a Green Communities grant the Town qualified for by adopting an energy-efficient building code in 2010.

What’s immediately obvious is the color. Right now it is possible to compare the two lamps, because Mass. Ave. is still on sodium while the side streets have the new LEDs. But Mass. Ave. (this is a blog about Mass. Ave.) will be included eventually.

The view is south on Henderson St. showing a new LED in the foreground at upper left and two sodium lamps on the opposite side of Mass. Ave in the background.

The LED light is much nearer to the camera so it looks brighter, but I thought the intensity of the new lamp is equivalent to that of the old. However, the photo does accurately show the dramatic difference in color.

Sodium lamps are notoriously orange, though I suppose we’ve all gotten used to that. The LED light shows us what we’ve been missing. Ironically the Town made a push to upgrade the lighting to sodium just six years ago. The switch was from even-less-efficient mercury-vapor lamps. That’s progress, and I say that without a trace of irony.

The nights have been pretty mild and you can go out and see for yourself. If you look closely you can make out two twin rows of 5 LED clusters (for a total of 20, that is) in each of the new lamps. Not sure how many LEDs that is, maybe 80?

There’s more background on the Town’s web page about the upgrade, including this:

Street lighting is one of the Town’s largest utility bill and over the last several years the Town has taken steps to reduce this cost. Six years ago the Town converted to high pressure sodium streetlights (HPS) which resulted in an annual reduction in the street lighting bill of $90,000 and cut the energy consumption in half, from 2.4 million kWh to 1.2 million kWh. Today, LED technology offers additional opportunities for savings and improved safety.  LEDs are twice as energy efficient as HPS lights, provide a 300% improvement in color rendering, better overall distribution of light, and last twice times as long as the lamps they replace, further reducing maintenance costs.

I add that besides saving the Town money this upgrade avoids new generation and transmission-and-distribution investment, and probably prolongs the life of NStar’s equipment. That means lower electric bills and more reliability for everyone.


1 comment so far

  1. dr2chase on

    LEDs also work better in cold weather. As to durability — I have some power LEDs mounted on my kids’ (and my) bikes, not really even shielded from the weather. Imagine anything made from glass, bolted to a teenager’s bike (did you know that you can crack a ball bearing in half if you hit a curb hard enough?), lasting for years and years.

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