Posted by Morris Dovey on July 10, 2011, 9:28 pm
These folks just gained some pretty good bragging rights:
"Big day for CSP as Gemasolar feeds the grid for 24 hours
Torresol’s Gemasolar power-tower installation has become the world's
first concentrating solar power (CSP) plant to feed an uninterrupted
supply of electricity into the grid over 24 hours."
It's only a 19.9MW plant and they say this plant won't do that
year-round, but it's a major step forward...
Posted by andrew on July 11, 2011, 6:39 pm
Morris Dovey wrote:
The 400C delta T across the heat exchange to the salt looks a bit wasteful??
Posted by Morris Dovey on July 11, 2011, 7:55 pm
On 7/11/11 1:39 PM, andrew wrote:
Right - it /is/ Spain - and I got the info from an NZ, so I don't know
how I managed to screw that up. :-/ Thanks!
It is a large âˆ†T, but that didn't surprise me so much - the losses do
seem to increase rapidly as the temperature goes up.
I've been edging toward experimenting with target geometry to see if it
can be used to reduce some of that loss - and if interested, you're
welcome to have a look at
The nay-sayers' favorite rejoinder to solar power advocacy is "Yeah, but
what about the time between sunset and dawn?" - so I'm pleased to see a
demonstration that overcomes that objection, and I'm not particularly
put off by any lack of efficiency in the initial implementation.
Now that it's been shown to work, perhaps more people will take an
interest in supporting efforts to make it work better.
Posted by andrew on July 11, 2011, 9:45 pm
Morris Dovey wrote:
Yes and that's why I would have thought going for this option was less than
Interesting and too clever for me. Where I live (51N) there's not a lot of
direct sunlight so PV trumps other solar to electricity. On the large scale
solar high temperature thermal seems to be a less resource intensive means.
As far as I can make out all these concentrators do is to increase the
angle at which the photons come from to balance the fact that the target re
radiates through 2PI steradians. I've been told of a theoretical nanotube
solution that does the same by making the emitter effectively the same
angle as the receiver, but I don't know if it is done in practice.
My main point would be that with very high voltage DC electricity can be
transmitted over large distances and high head hydro is an efficient means
of storage. In Europe and North Africa there are too many international
boundaries to negotiate but in north America...
Posted by Morris Dovey on July 12, 2011, 1:07 am
On 7/11/11 4:45 PM, andrew wrote:
I'm at 41.6°N 93.6°W so I have slightly longer days; and the jet stream
delivers more arctic high pressure systems (with crystal-clear skies)
during the cool half of the year - and we usually have a fair amount of
clear weather during summer and early autumn. It's a little better than
what you have but nowhere near as good as in the desert southwest.
I don't mind saying that there are times when we'd really appreciate the
loan of the gulfstream to temper the winter cold. ;-)
They do a little more - they allow designing systems which benefit from
higher operating temperatures. I have an interest in Carnot cycle
engines - and their efficiency is determined by the difference between
their "hot" side and their "cold" side temperatures; and it's generally
a lot easier/more economical to concentrate more input to the hot side
than it is to cool the cold side. I'm hoping to run my next solar engine
with a 400°C hot side for exactly that reason.
I don't either - but I suspect we'll be hearing a lot more. At some
point the entire receiver may be carbon.
I think you're under-estimating the considerable talents of North
American politicians (and energy suppliers) for courageously stepping
forward to rescue defeat from the jaws of victory.