Tim Keating said:
On Fri, 16 Sep 2005 12:53:21 GMT, "daestrom"
True. But tracker systems raise your prices quite a bit above $4/watt,
add
annual maintenance costs, reduce reliability and shortens expected plant
life.
Tracker cost drop's significantly with scale of economy and on
site manufacturing.
[/QUOTE]
Should, but has it yet?
Trackers are simple electro/mechanical devices.. Not all that
much to go wrong.. As for reliability and time to repair represents
an insignificant impact.. As for overall lifespan.. No change.. If
anything PV's will last longer since they can be oriented to mitigate
the effects of extreme weather. (high winds, hail, etc..)
Steam turbines are incredibly simple devices. So are centrifugal pumps.
Just spinning rotors mounted on a couple of bearings. Yet they require
maintenance every year or two. Tracking mechanisms have to be lubricated,
cleaned of dirt, bugs, whatever, and be re-aligned occasionally. Moving
parts = maintenance.
There are plenty of PV's used in long term installations... I.E.
Remote data loggers, many of which are still located in urban
locations. (gas, oil lines, etc)..
How many of them have been in service for 30 years without major
maintenance? *That's* the question, isn't it?
And there are reliable techniques to accelerate aging and determine
useful lifespan. (I.E. PV's typical twenty year warrantee's reflect
the results of that testing.)
NO...
As NG and Oil costs increase.. their kWh output per dollar DROPS...
I.E. LOWER..
Okay, I see how you mean. Yes, as fuel prices rise, the number of kwh
generated per dollar drops.
no more than $0.30 per watt..
Materials used to build trackers are not all that energy
intensive.
Guess it depends on your idea of 'not all that energy intensive'. But we
were talking costs. A 6 m^2 panel might need 75 to 100 lb of steel, and a
few pounds of copper and other specialties. So an approximately 900 watt
unit takes 100 lb of steel?? (remember, you want this thing to last for
quite a few years). Can you really get a good tracking mechanism for a 6
m^2 panel for just $270??
Nothing misleading... It's a real live number....
Divide yearly output by (total capacity*hours/day*days/year)..
The misleading part is that their capacity factor reduction is by *choice*,
not dictated by physics or plant equipment. Which is what you seem to be
implying when you point out that tracking PV capacity factor is not much
lower than fossil.
A plant that has very low fuel costs, and high capital costs would *choose*
to run 24/7 as a base load unit (which they do). This is exactly what coal
and nuclear do. Base load plants have capacity factors in the 80 and 90%
range. And if the base load in an area won't support running such a plant
24/7, then smart folks don't try and build another one there.
Peaking plants must have a very low $/watt capital cost since they will
*not* be run 24/7. With low capital costs and intermittent operation, they
can have a high fuel cost and still be economical.
The fact that the *average* of a lot of 80-90% base load plants, and 10-25%
peak-load plants is 50% doesn't tell us what the true reliability of a steam
or GT plant actually is.
PV just doesn't have that *choice*. Because PV has a high capital cost and
zero fuel costs, the right 'choice' would be to run it 24/7 also. But
physics and sunshine just will not allow that choice.
Economically, PV has the worst of both worlds. They have a high capital
cost and can only run intermittently, just the opposite of what one wants.
The fact that fuel costs are zero helps a lot, but you still have to pay
back those finance charges, and they can only operate < 50% of the time.
But, they won't operate if they can't get fuel...
Which will be a significant factor in the mid to longer term..
I.E. Neither NG nor OIl avail at any price..
In warm climates like Portugal, demand closely follows A/C usage,
which is a function of sun-light heating the surface.. Which makes
PVc's even more effective..
True. And their other sources of electricity are already very expensive, so
the economics can work for them. But not everywhere is like Portugal.
And it is true that PV's output nearly lines up with peak demand in many
areas (but not exactly, there's a couple of hour difference). So a PV plant
could charge a premium price for their output when its available.
You forgot expensive maintenance costs.
NG turbines don't have an unlimited lifespan, with no more than
ten or twenty thousand hours between EXPENSIVE major overhauls.
As for fuel costs.. they're increasing in leaps and bounds..
US NG costs are already at 8 cents per kWh and increasing..
Note: The above number doesn't represent KG's final cost.. one
MUST pay extra to get the NG delivered..
Short-term 'leaps and bounds' in fuel prices due to distribution and
processing limitations doesn't mean continued long-term prices will continue
to jump around as they have.
Heck, last holiday season, I gained weight in 'leaps and bounds'. If I
extrapolate from my gain between Dec 20th and Jan 3, I was gaining weight at
the rate of 260 lb per year. Statistics can be slippery when you don't use
them carefully.
Tell that to utilities which get no more than 50% utilization from
their current fossil plants..
Again with the disinformation. Utilities get much higher than 50% with
their base-load plants. And they get less than 50% from their peaking
plants. Apples and oranges. Sure, you can claim the *average* is 50%, but
that clouds the real issue. Some of those plants run in the 80-90% range.
It depends on the type and cost of each plant. No PV can ever hope to get
to those levels unless it's in orbit.
To lump all fossil plants together and average their utilization, regardless
of their operational role, is like lumping all modes of transportation
together and saying, "All modes of transportation can only carry, on
average, five passengers." It's technically true, but a meaningless point.
I'll take solar over Fossil fuels any day, and twice on sunday,
And what will you do any night?
it's the only way to a sustainable future..
In your opinion. What about renewable fuel sources, hydro, wind, and other
environmentally friendly technologies? There are a lot of options. PV can
be a part of our future, but there are many technologies to put into a well
diverse mix.
daestrom
