Re: Anyone moved to LED Lighting?

["Robert Green" <robert_green1963@xxxxxxxxx>]

"dgk" <dgk@xxxxxxxxxxxxx> wrote in message
news:0974j5tuphuiiv2en63d2ktd6d0p4cjcfg@xxxxxxxxxx
> On Tue, 22 Dec 2009 12:55:59 -0500, "Josepi" <JRM@xxxxxxxxxxxx> wrote:
>
>
> >
> >As aemeijers@xxxxxxx pointed out, it's very hard to accurately assess the
> >benefit of CFLs because of the complexity of the issue.  Few models seem
to
> >include the fact that in the winter, incandescent bulbs actually help
heat
> >the home.  The true cost/benefits of CFLs over tungsten bulbs are
incredibly
> >complex and that allows either side of the argument to spout nearly any
> >numbers they feel like.  All they need do is adjust the underlying
> >parameters or ignore facts like the future cost of removing mercury from
> >the environment the same way we're now removing asbestos.
> >
>
> You would also need to factor in extra cooling in summer which likely
> offsets the winter heat gain.

Not necessarily.  The days are (usually) much longer in the summer, so the
need for inside lighting is far less than in winter.  CO2 and other emission
savings are dependent on a lot of things, like whether dirty or pricey power
plants come on line to handle peak loads, whether the electricity would be
generated anyway, etc. and whether excess can be transferred or sold.

Remember, when building your model, to factor in the line loss involved in
transmitting power far away from its point of generation.  Also remember
that at night, voltage in most systems is at its highest because of the
excess generating capability, at least compared to the daytime load.  Does
having 122VAC at your outlet instead of 110VAC really translate into a
substantial emission savings?  I doubt it, but it's one of the ways power
plant operators cope with varying demand.

When people simply equate the money they save by using fluorescents into a
directly proportional amount of emission reduction, that's not a valid
comparison.  Electricity used at night, during "off-peak" hours is usually
cheaper for a reason.  It's partly because electricity has to be used when
generated or it's lost.  Each plant is different.  Some have to keep those
baseload generator turbines spinning, still outputting CO2, mercury, etc. to
be ready to cope with increased demands or generator failures.  How can
someone really calculate accurate savings without factoring all these
elements into their models?

You can't simply shut down a 200 ton turbine:  if they aren't kept spinning
their main shafts will deform and become unbalanced and they'll shake
themselves apart. You can't slow them down to lower the output.  When they
are generating electricity they have to run at a fixed RPM (3600, IIRC) to
create 60Hz AC power.  You can run them at lower torque, but they still need
to spin because some turbines are so massive that it takes hours to get them
up to speed and operating temperature.

Many power system guidelines specify that a significant percentage of their
operating reserve must come
from spinning reserves.  Why?  Because spinning reserves are more reliable,
have fewer issues related to "cold starts" and can respond to demand changes
immediately.  There are often considerable delays getting non-spinning
reserve generators on line and the only options for the operator may then be
to import the needed power or turn to brownouts.

So power savings, when it comes to generation, have to be calculated in
terms that account for a lot of things that are conspicuously absent from
the models and claims of those who believe they are saving the earth with
CFL bulbs.  Even shunting excess power to other parts of the grid has to be
examined closely because there are Joule heating losses that increase the
further away the power is shipped.  Do these savings model accurately
account for the cost of heating the air around the transmission lines when
shunting excess capacity to another part of the grid?  Doubtful.

Then there's the power factor issue to consider.  Are you really saving
money when the power company boosts the voltage at night to compensate for
the lower demand?   When I see statements that say CFLs will save precisely
X amount of dollars and create precisely X fewer emissions, I'm pretty
certain there's a lot of slop in those estimates.  Perhaps so much slop that
the claims come pretty close to meaningless guesses and wishful thinking.

As you examine each input to the model, you'll see that it grows incredibly
complex in a short time.  So much so that when you see a hard, fast number
you can be assured that someone made an awful lot of assumptions to get
there.  At night, when CFL bulbs are typically on, the issue is how much
less carbon and mercury is being emitted through CFL use?  It could be as
much as the greenest greenie claims or as little as next to nothing.

So far, I've not seen a study that even begins to account for all the known
inputs.  At their most primitive, studies simply compare watts and claim the
savings in kilowatt hours translates into equivalent drop in emissions.  But
that's totally fallacious without considering all the other elements of the
equation.

I will give you one common sense test.  How many power plants have been shut
down because of the allegedly tremendous savings we've realized by switching
to CFLs?  By the sound of the claims, you'd expect to see at least one or
two dozen, wouldn't you?

--
Bobby G.