Author Topic: Uh oh: "Detroit’s LED streetlights going dark after a few years"  (Read 2523 times)

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Offline james_s

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Re: Uh oh: "Detroit’s LED streetlights going dark after a few years"
« Reply #25 on: May 19, 2019, 08:20:12 pm »
It's not a myth, there are good ones that do last as specified, but there is a lot of junk too. Making something that lasts like that costs money, too many people shop by price.
 

Offline floobydust

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Re: Uh oh: "Detroit’s LED streetlights going dark after a few years"
« Reply #26 on: May 19, 2019, 08:57:03 pm »
How much more is the cost of "really good" LED streetlights?

Take two streetlight fixtures - (8hrs/day average on time):
lasts 10,000hrs or 3.4 years
lasts 30,000hrs or 10.3 years

So union labour has to drive out there, bucket loader truck and replace the cheap lamp fixture three times, compared to once for the expensive fixture. Guys get to keep a job changing streetlights. I'd guess several $100 taxpayer's cost to do this, plus disposal/warranty hassles.

The "really good" expensive LED streetlights may or may not be worth it?
 

Offline james_s

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Re: Uh oh: "Detroit’s LED streetlights going dark after a few years"
« Reply #27 on: May 19, 2019, 10:30:34 pm »
You're expecting logic and long term thinking, which is rare in bureaucratic projects like city streetlighting. When two contractors bid on a project, the one with the lowest bid is likely to win, two lights may have the same claims of lifespan and look similar on paper but one is half the cost. If it ends up failing years earlier the money has already been spent, the company that made it might be gone.
 

Offline floobydust

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Re: Uh oh: "Detroit’s LED streetlights going dark after a few years"
« Reply #28 on: May 19, 2019, 11:31:28 pm »
Yes it's a terrible analysis. It was a $185-million project.
Most of the numbers are about using fewer (65,000 vs 88,000) streetlights due to LED's luminance.
Preliminary quotes per cobrahead were $185 ea.
Savings almost $3M/yr in electricity. No figures for any maintenance costs  :palm:

"Maintenance savings are more difficult to quantify than energy savings given the extraordinary
circumstances surrounding the failed condition of the previous system. Certainly the conventional need for relamping fixtures every 4-5 years will be eliminated following the substitution of LED luminaires, although they eventually need replacement as well (perhaps on a 15-20 year cycle)."

Restoring Detroit’s Street Lighting System pdf
 

Offline IDEngineer

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Re: Uh oh: "Detroit’s LED streetlights going dark after a few years"
« Reply #29 on: May 20, 2019, 12:03:43 am »
You're expecting logic and long term thinking, which is rare in bureaucratic projects like city streetlighting. If it ends up failing years earlier the money has already been spent, the company that made it might be gone.
The best public contracts I've seen include a bond that the contractor must post against future claims. If the company goes out of business, the bond helps pay for it rather than the entire burden falling on the taxpayers. This protects the public from the standard dodge of "Do the job, then close that company and open a different one to leave the liability behind". I've most often seen this done for road construction where the new surface is supposed to be "guaranteed" for 10-20 years of useful life. The bond allows another company to come in and repair/resurface if necessary within the guarantee period.

The cynic in me says that politicians don't always do this because they are in cahoots with the bidders.
 
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