Interesting. Article on how the upcoming solar eclipse will temporarily
reduce US energy generation by ~9MW due to loss of solar, requiring gas
and hydro reserves to be brought online.

"During the upcoming Aug. 21 eclipse, operators of giant solar fields
from California to the Carolinas will rely on power from fast-start
natural gas generators as well as hydroelectric plants and other sources
to fill the gaps as the sky darkens. The celestial event, the first
total solar eclipse visible in the lower 48 states since 1979, will
provide owners of gas turbines a chance to shine even as the fossil-fuel
is expected to be displaced over time by solar and wind energy"

http://fortune.com/2017/08/09/total-solar-eclipse-natural-gas/

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

9GW?

On 13/08/17 04:06, Mike Tomlinson wrote:

Interesting. Article on how the upcoming solar eclipse will temporarily
reduce US energy generation by ~9MW due to loss of solar, requiring gas
and hydro reserves to be brought online.

"During the upcoming Aug. 21 eclipse, operators of giant solar fields
from California to the Carolinas will rely on power from fast-start
natural gas generators as well as hydroelectric plants and other sources
to fill the gaps as the sky darkens. The celestial event, the first
total solar eclipse visible in the lower 48 states since 1979, will
provide owners of gas turbines a chance to shine even as the fossil-fuel
is expected to be displaced over time by solar and wind energy"

http://fortune.com/2017/08/09/total-solar-eclipse-natural-gas/

I am sure they can cope as the same thing happens every night.


--
Karl Marx said religion is the opium of the people.
But Marxism is the crack cocaine.

Well yes but hang on a moment what about night times?

Its only going to be less than an hour or so and its all over.

I'm wondering why this is a problem, if it is one that is.

Never mind Sodium air batteries are 'just round the corner' as they have
been for ten years or more...:-)
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Mike Tomlinson" wrote in message
...

Interesting. Article on how the upcoming solar eclipse will temporarily
reduce US energy generation by ~9MW due to loss of solar, requiring gas
and hydro reserves to be brought online.

"During the upcoming Aug. 21 eclipse, operators of giant solar fields
from California to the Carolinas will rely on power from fast-start
natural gas generators as well as hydroelectric plants and other sources
to fill the gaps as the sky darkens. The celestial event, the first
total solar eclipse visible in the lower 48 states since 1979, will
provide owners of gas turbines a chance to shine even as the fossil-fuel
is expected to be displaced over time by solar and wind energy"

http://fortune.com/2017/08/09/total-solar-eclipse-natural-gas/

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

En el artículo ,
therustyone escribió:

9GW?

Yes. Just testing.



--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

En el artículo , Chris Hogg
escribió:

But in terms of the US total generating capacity, it's trivial (and I
know you meant 9GW, but it's still trivial, less than 1% in fact).

Agreed. I found it interesting from the viewpoint of having the
necessary alternative capacity available and ready to bring online at a
moment's notice to cope with the sudden loss of solar.

I read an interesting article a couple weeks ago about the Germans
having trouble operating their (remaining) nukes in load-following mode.
Apparently it makes them unreliable and shortens their lifetime.
Something I hadn't expected, given the reaction can me controlled/varied
by using the control rods.

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

En el artículo , The Natural Philosopher
escribió:

I am sure they can cope as the same thing happens every night.

No ****, Sherlock. That 40-year-old theoretical degree stands you in
good stead, doesn't it?

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

On 13/08/2017 11:52, Huge wrote:
On 2017-08-13, Mike Tomlinson wrote:
En el artÃ*culo , Chris Hogg
escribió:

But in terms of the US total generating capacity, it's trivial (and I
know you meant 9GW, but it's still trivial, less than 1% in fact).

Agreed. I found it interesting from the viewpoint of having the
necessary alternative capacity available and ready to bring online at a
moment's notice to cope with the sudden loss of solar.

I read an interesting article a couple weeks ago about the Germans
having trouble operating their (remaining) nukes in load-following mode.
Apparently it makes them unreliable and shortens their lifetime.
Something I hadn't expected, given the reaction can me controlled/varied
by using the control rods.

I used to work with someone who had previously worked on a reactor
simulations. He said that nuclear reactors are like wobbly jelly. If you
put control rods in "here", there are responses over "there" and it
all takes (a long) time to make fine adjustments.



And with at least some designs it's a "bad thing" to keep mechanically
stressing the control rods; and even if those are designed for the job -
or other means used to control output - there's the problem of thermally
stressing the whole thing. That shortens the lifetime which, coming on
top of running at less than full capacity, means load following is a
double-bugger-up to the economics of reactors (ie high capital cost, low
marginal cost of output).

--
Robin
reply-to address is (intended to be) valid

En el artículo , Huge
escribió:

I used to work with someone who had previously worked on a reactor
simulations. He said that nuclear reactors are like wobbly jelly. If you
put control rods in "here", there are responses over "there" and it
all takes (a long) time to make fine adjustments.

That's... confidence-inspiring.

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

Chris Hogg wrote:

in terms of the US total generating capacity, it's trivial (and I
know you meant 9GW, but it's still trivial, less than 1% in fact).
They lose more than that every night.

It's the rate of ramping up and down the non-solar sources that's the
issue, seems like they're going to disconnect the big solar farms in
advance, so it just leaves the Californian versions of Harry to worry
about, who will all of a sudden be asking the grid to make up their loss.

"Brian Gaff" wrote in message news

Well yes but hang on a moment what about night times?

Its only going to be less than an hour or so and its all over.

I'm wondering why this is a problem, if it is one that is.

Never mind Sodium air batteries are 'just round the corner' as they have
been for ten years or more...:-)
Brian

It is your understanding of *where* the corner is in relation to where we
are now that is the problem :-|

On Sun, 13 Aug 2017 08:48:51 +0100, The Natural Philosopher wrote:

On 13/08/17 04:06, Mike Tomlinson wrote:

Interesting. Article on how the upcoming solar eclipse will
temporarily reduce US energy generation by ~9MW due to loss of solar,
requiring gas and hydro reserves to be brought online.

"During the upcoming Aug. 21 eclipse, operators of giant solar fields
from California to the Carolinas will rely on power from fast-start
natural gas generators as well as hydroelectric plants and other
sources to fill the gaps as the sky darkens. The celestial event, the
first total solar eclipse visible in the lower 48 states since 1979,
will provide owners of gas turbines a chance to shine even as the
fossil-fuel is expected to be displaced over time by solar and wind
energy"

http://fortune.com/2017/08/09/total-solar-eclipse-natural-gas/

I am sure they can cope as the same thing happens every night.

Ramp down and ramp up are not usually so quick, though. Time to wind the
gas up and then down is quite short ISTR.

However a fast moving thunder cloud could have a similar effect, no doubt.

Cheers


Dave R

--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On 13/08/2017 04:06, Mike Tomlinson wrote:

Interesting. Article on how the upcoming solar eclipse will temporarily
reduce US energy generation by ~9MW due to loss of solar, requiring gas
and hydro reserves to be brought online.

And, apparently, there's similar planning going on for the near total
eclipse in the UK in 2026.

--
F

En el artículo , Chris Hogg
escribió:

Yes, I saw that. Probably either Mearns' blog or WUWT; can't remember
now

I'll have a furtle and see if I can find it again. Possibly PEI.

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

On 13/08/17 11:38, Mike Tomlinson wrote:
En el artÃ*culo , Chris Hogg
escribió:

But in terms of the US total generating capacity, it's trivial (and I
know you meant 9GW, but it's still trivial, less than 1% in fact).

Agreed. I found it interesting from the viewpoint of having the
necessary alternative capacity available and ready to bring online at a
moment's notice to cope with the sudden loss of solar.

I read an interesting article a couple weeks ago about the Germans
having trouble operating their (remaining) nukes in load-following mode.
Apparently it makes them unreliable and shortens their lifetime.
Something I hadn't expected, given the reaction can me controlled/varied
by using the control rods.

shows how little you know.

waste products change nature under throttled conditions



--
How fortunate for governments that the people they administer don't think.

Adolf Hitler

On 13/08/17 11:39, Mike Tomlinson wrote:
En el artÃ*culo , The Natural Philosopher
escribió:

I am sure they can cope as the same thing happens every night.

No ****, Sherlock. That 40-year-old theoretical degree stands you in
good stead, doesn't it?

What a complete arsehole you really are as well as stupid,.


--
How fortunate for governments that the people they administer don't think.

Adolf Hitler

On 13/08/17 12:09, Mike Tomlinson wrote:
En el artÃ*culo , Huge
escribió:

I used to work with someone who had previously worked on a reactor
simulations. He said that nuclear reactors are like wobbly jelly. If you
put control rods in "here", there are responses over "there" and it
all takes (a long) time to make fine adjustments.

That's... confidence-inspiring.

and wrong for later reactors.


--
"It is an established fact to 97% confidence limits that left wing
conspirators see right wing conspiracies everywhere"

On 13/08/17 12:10, Chris Hogg wrote:
On Sun, 13 Aug 2017 11:38:02 +0100, Mike Tomlinson
wrote:

En el artÃ*culo , Chris Hogg
escribió:

But in terms of the US total generating capacity, it's trivial (and I
know you meant 9GW, but it's still trivial, less than 1% in fact).

Agreed. I found it interesting from the viewpoint of having the
necessary alternative capacity available and ready to bring online at a
moment's notice to cope with the sudden loss of solar.

I read an interesting article a couple weeks ago about the Germans
having trouble operating their (remaining) nukes in load-following mode.
Apparently it makes them unreliable and shortens their lifetime.
Something I hadn't expected, given the reaction can me controlled/varied
by using the control rods.

Yes, I saw that. Probably either Mearns' blog or WUWT; can't remember
now. But it may explain why UK nukes' output is as steady as a rock.

No, it doesn't.

Nukes are run flat out because the fuel costs nowt and thats the most
profitable mode.

A few are throttled back a bit because of weak boilers.

France throtlles its fleet extensivley because they have more than enough.

Works OK with new fuel rods but later in xenon poisoning starts to make
it more difficult.


--
"It is an established fact to 97% confidence limits that left wing
conspirators see right wing conspiracies everywhere"

On 13/08/17 12:16, Andy Burns wrote:
Chris Hogg wrote:

in terms of the US total generating capacity, it's trivial (and I
know you meant 9GW, but it's still trivial, less than 1% in fact).
They lose more than that every night.

It's the rate of ramping up and down the non-solar sources that's the
issue, seems like they're going to disconnect the big solar farms in
advance, so it just leaves the Californian versions of Harry to worry
about, who will all of a sudden be asking the grid to make up their loss.

Ramp rate isn't that huge. Hydro can easily deal with that if they are
ready.

Or if not do the obvious and disconnect some solar early.

Its a non=story.



--
"It is an established fact to 97% confidence limits that left wing
conspirators see right wing conspiracies everywhere"

On 13/08/17 12:45, F wrote:
On 13/08/2017 04:06, Mike Tomlinson wrote:

Interesting. Article on how the upcoming solar eclipse will temporarily
reduce US energy generation by ~9MW due to loss of solar, requiring gas
and hydro reserves to be brought online.

And, apparently, there's similar planning going on for the near total
eclipse in the UK in 2026.

Its not hard.

Just switch the solar off anyway.

Oh. It's on peoples rooves. hahahahaha.

--
There is something fascinating about science. One gets such wholesale
returns of conjecture out of such a trifling investment of fact.

Mark Twain

On 13/08/2017 11:38, Mike Tomlinson wrote:
En el artÃ*culo , Chris Hogg
escribió:

But in terms of the US total generating capacity, it's trivial (and I
know you meant 9GW, but it's still trivial, less than 1% in fact).

Agreed. I found it interesting from the viewpoint of having the
necessary alternative capacity available and ready to bring online at a
moment's notice to cope with the sudden loss of solar.

I read an interesting article a couple weeks ago about the Germans
having trouble operating their (remaining) nukes in load-following mode.
Apparently it makes them unreliable and shortens their lifetime.
Something I hadn't expected, given the reaction can me controlled/varied
by using the control rods.


Depends on the thermal mass in the core.

IIRC the AGR reactors we had(have?) can take days to warm up and
presumably as long to cool down.

Boiling water reactors are somewhat quicker to respond.

En el artículo , Chris Hogg
escribió:

It's here http://tinyurl.com/yb6ebz4v

Thank you. The Taggespiegel link in the first para is the one I saw
(auf deutsch).

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

"David" wrote in message
...
On Sun, 13 Aug 2017 08:48:51 +0100, The Natural Philosopher wrote:

On 13/08/17 04:06, Mike Tomlinson wrote:

Interesting. Article on how the upcoming solar eclipse will
temporarily reduce US energy generation by ~9MW due to loss of solar,
requiring gas and hydro reserves to be brought online.

"During the upcoming Aug. 21 eclipse, operators of giant solar fields
from California to the Carolinas will rely on power from fast-start
natural gas generators as well as hydroelectric plants and other
sources to fill the gaps as the sky darkens. The celestial event, the
first total solar eclipse visible in the lower 48 states since 1979,
will provide owners of gas turbines a chance to shine even as the
fossil-fuel is expected to be displaced over time by solar and wind
energy"

http://fortune.com/2017/08/09/total-solar-eclipse-natural-gas/

I am sure they can cope as the same thing happens every night.

Ramp down and ramp up are not usually so quick, though. Time to wind the
gas up and then down is quite short ISTR.

However a fast moving thunder cloud could have a similar effect, no doubt.

Quite different actually, nothing even remotely like as large and area
affected.

On 8/13/2017 11:38 AM, Mike Tomlinson wrote:
En el artÃ*culo , Chris Hogg
escribió:

But in terms of the US total generating capacity, it's trivial (and I
know you meant 9GW, but it's still trivial, less than 1% in fact).

Agreed. I found it interesting from the viewpoint of having the
necessary alternative capacity available and ready to bring online at a
moment's notice to cope with the sudden loss of solar.

I read an interesting article a couple weeks ago about the Germans
having trouble operating their (remaining) nukes in load-following mode.
Apparently it makes them unreliable and shortens their lifetime.
Something I hadn't expected, given the reaction can me controlled/varied
by using the control rods.

Going back to Privatisation and the original Pool system, it was
accepted that it was better for plant longevity not to load follow with
UK gas cooled reactors, and they had the happy concession of allowing to
stay on the grid once they had been scheduled. They couldn't be "forced
off" other than in exceptional circumstances. The old Pool system meant
they could always "bid zero", so as the cheapest plant they were always
scheduled on.

I believe it has all changed under NETA, but that is far too difficult
for this bear of little brain.

Load following leads to temperature cycling of fuel and all sorts of
other plant, giving thermal stress cycles and hence burning up the
fatigue life.

There are also some subtleties in the nuclear physics if the power
cycles are large.

My understanding is that the French pressurised water reactors are load
cycled somewhat, although of course they manage national demand
variations a lot by exporting surplus.

In fact the British AGRs do load cycle to some extent, because they have
to reduce power during "on-load" refuelling.

On 8/13/2017 12:09 PM, Mike Tomlinson wrote:
En el artÃ*culo , Huge
escribió:

I used to work with someone who had previously worked on a reactor
simulations. He said that nuclear reactors are like wobbly jelly. If you
put control rods in "here", there are responses over "there" and it
all takes (a long) time to make fine adjustments.

That's... confidence-inspiring.

It's a bit simplistic, but there is some truth to it.

Back when Fast Reactors were still under active consideration, there was
some perception that these might be nasty and difficult to control,
compared to the more lumbering thermal reactors.

One of the top management guys (I forget who) used to cover this in
talks to the "informed" public.

His analogy was that people thought of thermal and fast reactors as
being a bit like lorries and racing cars, and that this was, in fact,
correct. In those days, as long as they were not actually being driven
at racing speeds, racing cars were relatively well-behaved and easy to
control. Articulated lorries were not as it was all too easy to
jack-knife. This phenomenon can be described by engineers as a "spatial
instability". And in fact physically large thermal reactors like the old
Magnox plant do have thermal instabilities. You get temperature
oscillations across the diameter (timescale tens of seconds) where one
half rises while the other cools, and then this reverses. It's rather
like some of the vibration modes in a drum-skin. If you think of the
core as having four quadrants (N-S-E-W) you get oscillations where the
temperature of N and S rises while E and W falls, and so forth.

This sort of thing is a pain in the neck for operators, because
obviously you want the outlet gas to be as hot as possible, but there is
an upper temperature limit set by materials. If temperatures are
oscillating and you don't breach the maximum temperature limit, then
your *average* temperature is below the optimum.

However, these oscillations don't run out of control in UK reactors
because other intrinsic factors take over. The reactors have a negative
temperature coefficient of reactivity, for various reasons a rise in
temperature automatically has the same effect as slightly inserting the
control rods.

On 8/13/2017 3:38 PM, dennis@home wrote:
On 13/08/2017 11:38, Mike Tomlinson wrote:
En el artÃ*culo , Chris Hogg
escribió:

But in terms of the US total generating capacity, it's trivial (and I
know you meant 9GW, but it's still trivial, less than 1% in fact).

Agreed. I found it interesting from the viewpoint of having the
necessary alternative capacity available and ready to bring online at a
moment's notice to cope with the sudden loss of solar.

I read an interesting article a couple weeks ago about the Germans
having trouble operating their (remaining) nukes in load-following mode.
Apparently it makes them unreliable and shortens their lifetime.
Something I hadn't expected, given the reaction can me controlled/varied
by using the control rods.


Depends on the thermal mass in the core.

IIRC the AGR reactors we had(have?) can take days to warm up and
presumably as long to cool down.

Boiling water reactors are somewhat quicker to respond.


It's not so much the thermal mass of the core, it is that the power is
deliberately raised gradually to allow things to heat up uniformly, thus
limiting the thermal stresses. It's the thermal diffusivity that
matters, not the specific heat.

It's (sort of) the same reason that if you are towing a dead car, you
edge forward until the tow rope is tight, and then pull off gently. Not
bothering to do this and accelerating hard with a slack tow-rope leads
to unintended consequences.

En el artículo . com,
dennis@home escribió:

IIRC the AGR reactors we had(have?)

We still have them. Hinkley B has just auto-tripped due to a gas pump
failure.

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West

En el artículo ,
newshound escribió:

This phenomenon can be described by engineers as a "spatial
instability". And in fact physically large thermal reactors like the old
Magnox plant do have thermal instabilities. You get temperature
oscillations across the diameter (timescale tens of seconds) where one
half rises while the other cools, and then this reverses. It's rather
like some of the vibration modes in a drum-skin. If you think of the
core as having four quadrants (N-S-E-W) you get oscillations where the
temperature of N and S rises while E and W falls, and so forth.

Presumably this is less of an issue in modern reactors because the
materials science is better understood?

However, these oscillations don't run out of control in UK reactors
because other intrinsic factors take over. The reactors have a negative
temperature coefficient of reactivity, for various reasons a rise in
temperature automatically has the same effect as slightly inserting the
control rods.

I seem to remember that the RBMK reactor at Chernobyl had a positive
CoR, and this was one of the major factors that contributed to the
accident.

That was a fascinating post, thank you.

--
(\_/)
(='.'=) "Between two evils, I always pick
(")_(") the one I never tried before." - Mae West