City of Ann Arbor converting more streetlights to LED
A look at some Ann Arbor streetlights that have been converted to LEDs in front of a downtown restaurant sign.
The City of Ann Arbor is converting more city streetlights to light-emitting diodes, or LEDs, in the next year after seeing at least $10,000 in energy savings in 2009 from using the lights.
City Energy Programs Manager Andrew Brix said he estimates the city saved an additional $40,000 in maintenance costs last year from having LED lights instead of incandescent street lights.
In all, the city owns about 2,000 streetlights and has about 800 additional streetlights it expects to switch over by the end of 2011. The changeover is being funded by a $1.2 million Energy Efficiency and Conservation Block Grant.
There are about 7,000 streetlights throughout the city, including about 5,000 lights owned by DTE Energy, with energy costs paid by the city. The city energy office is evaluating whether it would save money in energy costs by purchasing those lights and installing the LED street lights.
In 2009, the energy office said it was able to save the city $153,000 in energy costs from streetlight and traffic light energy savings, as well as savings in natural gas costs from locking in prices earlier in the year.
Tina Reed covers health and the environment for AnnArbor.com. You can reach her at tinareed@annarbor.com, call her at 734-623-2535 or find her on Twitter @TreedinAA.
Comments
Walter McBroom
Mon, Feb 1, 2010 : 5:36 p.m.
"I'm not saying they aren't accurate, but I'd like to know how they were arrived at."- Craig Lounsbury These numbers can be arrived at by simple math. 2000 streetlights using 298 watts of energy per hour (250 for the bulb, 48 for the ballast) averaging 12 hours a day for 365 days. This gives us 2,610,480 kWh used at a rate of $0.08 cents per kWh for a total of $208,838.40 electric cost to run the existing lights. Now compare it to 2000 LED Streetlights using 80 watts of energy per hour averaging 12 hours a day for 365 days. This gives us 700,800 kWh used at a rate of $0.08 cents per kWh for a total of $56,064.00 electric cost to operate the LED lights. Now here is the simple math part. $208,838.40 - $56,064.00 = $152,774.40 in total electrical savings in one year. I admit I changed the cost of electricity to $0.08 per kWh to get these numbers to meet with the $153,000 savings. I am sure the city does not pay as much for the electricity if they also are including the traffic light savings. If you know the true cost you can adjust the numbers to get the accurate savings for just the streetlights alone. Hope this helps. Walter McBroom TEU Services, Inc www.ledbyteu.com
C6
Fri, Jan 15, 2010 : 11:13 p.m.
"Don't most streetlights have mercury vapor lamps rather than incandescent?" Most street lights use a high intensity discharge (HID) type lamp, which could be mercury vapor, but typically around Ann Arbor however thankfully isn't. High pressure sodium street lights are more typical here. Here's how to tell the difference. Mercury Vapor (MV) lamps produce light with a bluish-green tint. These are roughly equal in efficiency with fluorescent bulbs, but grow dimmer with age while still consuming the same electrical power. MV fixtures are usually seen around Ann Arbor as the backyard "glare bombs" that have been installed on residental garages and as "yard lights". Metal Halide (MH) lamps are similar to MV, but utilize other metallic elements so that they produce a "white" light. The color from each individual lamp tends to shift a bit from white however, so a row of street lights might each appear to be a slightly different "off-white". MH lamps have a better efficiency than Mercury vapor, but a shorter life. They too suffer from decreasing light output as they age. Some parking lots around Ann Arbor are lit with MH lamps. As stated earlier, High Pressure Sodium (HPS) lamps are the most common type of HID source used in street lights here. They produce an amber-colored light that's uniform from individual lamp to lamp. They're more efficient that MV or MH lamps. HPS lamps have less of a light decrease as they approach end of life, but can tend to cycle off and a minute or so later back on again as they age. Low Pressure Sodium (LPS) is by far the most energy efficient type of HID street lighting. These produce a yellowish light that's monochromatic however and therefore provide poor color rendition that many people find objectionable. Everything illuminated by LPS lamps will appear either orange-yellow, black, or some shade in between. The last I noticed, LPS lamps were used to light the parking on the east side of Ann Arbor's Federal Building. The light output from LPS does not decrease with age, but the power consumption does increase with age. I hope this information is helpful.
Anonymous Due to Bigotry
Fri, Jan 15, 2010 : 5:36 p.m.
I believe the problem with LED lights getting covered with ice/snow was a problem with TRAFFIC lights, not street lighting. I believe we're talking about street lighting here. Regardless, if LED traffic or street lights get covered with ice or snow it could probably be solved by having a work crew patrol around clearing them off or something, but that obviously has to be factored into the cost. If it's cost effective then great! If not then hold off until it becomes cost effective.
pooh bear
Fri, Jan 15, 2010 : 4:50 p.m.
I'm so glad we are converting to LEDs while so many streets are without any lights at all! Drive down Washtenaw near the CCRB, the block of S. Division that just had all that fancy infrastructure work or the 3 blocks of E. Huron near the construction for the Palace of Justice.
Spencer Thomas
Fri, Jan 15, 2010 : 4:33 p.m.
Don't most streetlights have mercury vapor lamps rather than incandescent? The disposal problem for compact fluorescents is real. I've got an increasing pile of these bulbs in the basement waiting for me to take them somewhere for disposal. I love that they generate less heat; I hate that they are not dimmable (unless I pay a *lot* more for them).
brad
Fri, Jan 15, 2010 : 11:45 a.m.
Craig: If replacing your bulbs requires crews with specialized trucks, you'd want a longer-lasting bulb. From the meeting, $83/light per year is from reduced maintenance ($21/light from energy; payback is 4.4 years). I'm also suspicious of the estimates, but reduced maintenance seems real. Last, the City received $2.2m in grants in 2009. Without a manager, would that amount be as high?
Craig Lounsbury
Fri, Jan 15, 2010 : 11:09 a.m.
"First of all, the project is funded by a grant - which means"... its coming out of our collective left pocket instead of our collective right pocket. I'm not against saving money and being green, just show me how the numbers are arrived at. I have filled my house with assorted fluorescent lights. (And yes I know they aren't the same as LED's) When I factor the increased purchase cost, the fact that they do NOT in my experience last as long as claimed, I have to pay AND drive to properly dispose of them, they really don't save me anything. They may actually cost me. So hypothetical numbers on saving are open to suspicion as far as I'm concerned.
C6
Fri, Jan 15, 2010 : 10:33 a.m.
Think of the financial health our city would have if every city manager could save we taxpayers the equalivant of their compensation package with just one of their projects. Not only do solid state (LED) light sources use only a fraction of the energy consumed by the older technology sources they replace, but they're also typically designed to direct their illumination to where it's actually needed rather than up into the sky or a half mile down the street. Decorative sidewalk lighting like the city is replacing with the LEDs shown above, typically misdirect most of their light and waste up to 70 cents of every dollar spent to power them. Typical Cobra Head street lights can waste as much as 30% of the light generated by their 120 watt lamps. Moving to LED technology is a smart move by the city, and I urge them to wrestle control of those 5,000 streetlights away from DTE.
breadman
Fri, Jan 15, 2010 : 10:04 a.m.
I reported a street light out months ago over a cross walk And too this date it is still out. There Are many child(ren) that cross in the dark for ie: the school bus and/or the aata bus. I am talking about a marked cross walk!!!!
tracyann
Fri, Jan 15, 2010 : 9:53 a.m.
@ dading - it's actually traffic lights that had the problems with ice and such. This article is referring to street lights.
xmo
Fri, Jan 15, 2010 : 9:28 a.m.
I am just glad to hear that "going green" can save money. Usually, the only benefit is saving the planet while costing us more money.
breadman
Fri, Jan 15, 2010 : 8:59 a.m.
I reported a street light out months ago over a cross walk And too this date it is still out. There Are many child(ren) that cross in the dark for ie: the school bus and/or the aata bus. I am talking about a marked cross walk!!!!
a2huron
Fri, Jan 15, 2010 : 8:45 a.m.
For some reason, I thought the city had already replaced all lights. I do agree that there appears to be a legitimate concern regarding traffic lights (not this winter, so far).
dading dont delete me bro
Fri, Jan 15, 2010 : 8:36 a.m.
are they going to include heaters w/the LED's? tests have shown that the LED do not generate enough heat to melt snow and ice off the lenses...thus creating traffic hazards. google it. doh!
Craig Lounsbury
Fri, Jan 15, 2010 : 7:27 a.m.
If its true "In 2009, the energy office said it was able to save the city $153,000 in energy costs from streetlight and traffic light energy savings" I bet that would almost pay City Energy Programs Manager Andrew Brix's salary and fringe benefits. Call me cynical, never mind, I'll call myself cynical about the numbers. I'm not saying they aren't accurate, but I'd like to know how they were arrived at.