[EAS] On valuable artifacts:

[Mike McCarthy]

Ray,

It's not the disposal of incandescent bulbs....which are 99% 
recyclable.  It's the cost to operate and the resultant greenhouse gas 
emissions by the power plant to generate the power (along with the 
transmission losses.

Case in point.  In Illinois at a typical four lane intersection, there 
are at least twelve (often times more with dedicated turn lane 
signalling) 116W bulbs illuminated at any instant.  (Illinois has s 
standard of 3 signalling lights in all directions of travel.) Add in 
right and left turn blubs and that can easily swell to 20 or more at 
fully controlled intesectiona. On big 6 lane intersections, there could 
be as many as 28 lamps illuminated at once. 3.3KW draw.

Multiply the average of 2.0KW by 100,000 or so. The result is about 1/2 
of a single coal fired generation system (200+MW) just for traffic 
lights in Illinois running 24/365.

Across the USA, what are there, some 5M traffic lights on average with 8 
bulbs minimum operating at each? That's 5GW...or 6 coal plants.  I don't 
know the emission ratio of kw to tons of CO2 and other gases, but I seem 
to recall it's a lot. Not to mention the handling of coal ash which is 
lightly radioactive and requires special handling.

Focused LED lamps requires anywhere between 12% and 20% of comparable 
energy.

Next up is the replacement of high pressure/HID street lighting with 
LED's.  Chicago alone has over 100K street lights at 175-400W ea.  
That's the rest of the power plant and then some just for street 
lighting in one city.

So, by converting to LED lamps, Illinois alone will eliminate the need 
for at least one large sized coal fired plant for free public 
lighting...and allow that plant to be revenue producing generation 
capacity allocated for the next data center.....

MM

On 11/18/2012 8:00 AM, ray at electronicstheory.com wrote:
> Perhaps it is just me - but I can't seem to figure out how an 
> incandescent light bulb can be more harmful for the environment than a 
> mercury vapor bulb. For that matter - what is the proper method for 
> disposing of a mercury vapor bulb anyway? Isn't there some ecological 
> impact for allowing mercury vapor to just vent? Personally I think 
> that they are as good for the environment as switching from analog to 
> digital....but certainly doing so wouldn't have raised NEARLY as much 
> tax revenue. 
> Ray Dall Radio Frequency Engineer