It is
not taking off very quickly, but it could have a big impact.
rel="tag"
href="http://en.wikipedia.org/wiki/Raleigh%2C_North_Carolina">Raleigh,
NC agreed to the "
href="http://www.raleigh-nc.org/portal/server.pt/gateway/PTARGS_0_2_276_208_0_43/http%3B/pt03/dig_web_content/news/public/News-PubAff-Raleigh_And_Cree_Team_Up-20070214-090845.html">LED
City" initiative, joining with a company located nearby,
href="http://www.cree.com/">Cree Inc.
The initiative is to replace all civic lighting with
href="http://en.wikipedia.org/wiki/Light-emitting_diode"
rel="tag">light-emitting diodes (LEDs).
A few weeks ago,
href="http://en.wikipedia.org/wiki/Toronto" rel="tag">Toronto
href="http://www.semiconductor-today.com/news_items/NEWS_2007/JULY_07/LEDC_110707.htm">signed
up as well. Converting the streetlights in Toronto
should save about six million dollars per year in energy costs.
Now, Ann
Arbor is taking a half-step. They are
href="http://www.ci.ann-arbor.mi.us/Clerks/AgendaDocuments/2007/07-02-07/F-6.pdf">planning
(PDF file) to convert their downtown streetlights. It will
cost about $600,000, but should save $150,000 per year in energy costs.
The project will take two years, involving replacement of
1,400 streetlights.
A couple thoughts come to mind. Since LED's are more directional, this should reduce light pollution. And assuming they prove reliable, they'll save again as they should outlast the vapor lamps. Their savings could end up bigger than expected.
Also, such large-scale purchases will stimulate competition in manufacture of LED lamps, driving down prices.
Wow, gives me a whole different perspective on Raleigh. This actually sounds quite fantastic!
Are LEDs ready for streetlight use yet? I know they're great for traffic lights, where the ability to efficiently generate monochromatic radiation plays in their favor.
There are white LEDs, and some will emit 100 lumens each. It takes a lot of LEDs to get a bright enough light, but it can be done. The up-front cost is still an issue. But theoretically, they should last a really long time. If that turns out to be the case in actual use, then the city will save both on electricity, but also on labor costs.