I seem to remember someone posted here about a "virtual host" error when
trying to access gridwatch.templar but can't find the post.

I have the same thing on Firefox 8.0 running on Linux (Fedora 15); the
error "Virtual host not found on this server" appears, yet Firefox 8.0
running in an XP virtual host on the same box works.

Not whinging, just odd behaviour.

--
(\__/)
(='.'=)
(")_(")

In article , Mike Tomlinson
writes

I have the same thing on Firefox 8.0 running on Linux (Fedora 15); the
error "Virtual host not found on this server" appears, yet Firefox 8.0

Ignore me. I'd put "http://gridwatch.templar.co.uk" in the non-working
browser and "http://www.gridwatch.templar.co.uk" in the working one.

Suggestion: under the line "ServerName www.gridwatch.templar.co.uk", add
an alias "ServerAlias gridwatch.templar.co.uk" in httpd.conf.

--
(\__/)
(='.'=)
(")_(")

Mike Tomlinson wrote:
In article , Mike Tomlinson
writes

I have the same thing on Firefox 8.0 running on Linux (Fedora 15); the
error "Virtual host not found on this server" appears, yet Firefox 8.0

Ignore me. I'd put "http://gridwatch.templar.co.uk" in the non-working
browser and "http://www.gridwatch.templar.co.uk" in the working one.

Suggestion: under the line "ServerName www.gridwatch.templar.co.uk", add
an alias "ServerAlias gridwatch.templar.co.uk" in httpd.conf.

THAT wont work..cos gridwatch.templar.co.uk points at another server
entirely :-)

howver, that might be adjusted...

On 24/11/2011 11:58, Mike Tomlinson wrote:

I seem to remember someone posted here about a "virtual host" error when
trying to access gridwatch.templar but can't find the post.

I have the same thing on Firefox 8.0 running on Linux (Fedora 15); the
error "Virtual host not found on this server" appears, yet Firefox 8.0
running in an XP virtual host on the same box works.

Not whinging, just odd behaviour.

Seems to work OK here. BTW Wind power output is pegged to the endstop at
3.1GW and has been since 10am this morning. Maybe fsd should be 5.0GW

Regards,
Martin Brown

Martin Brown wrote:
On 24/11/2011 11:58, Mike Tomlinson wrote:

I seem to remember someone posted here about a "virtual host" error when
trying to access gridwatch.templar but can't find the post.

I have the same thing on Firefox 8.0 running on Linux (Fedora 15); the
error "Virtual host not found on this server" appears, yet Firefox 8.0
running in an XP virtual host on the same box works.

Not whinging, just odd behaviour.

Seems to work OK here. BTW Wind power output is pegged to the endstop at
3.1GW and has been since 10am this morning. Maybe fsd should be 5.0GW

the meter won't get damaged from a very short and *very* occasional
overload :-)


Regards,
Martin Brown

Chris Hogg wrote:
On Thu, 24 Nov 2011 16:14:52 +0000, Martin Brown
wrote:

On 24/11/2011 11:58, Mike Tomlinson wrote:
I seem to remember someone posted here about a "virtual host" error when
trying to access gridwatch.templar but can't find the post.

I have the same thing on Firefox 8.0 running on Linux (Fedora 15); the
error "Virtual host not found on this server" appears, yet Firefox 8.0
running in an XP virtual host on the same box works.

Not whinging, just odd behaviour.

Seems to work OK here. BTW Wind power output is pegged to the endstop at
3.1GW and has been since 10am this morning. Maybe fsd should be 5.0GW

Regards,
Martin Brown

Forgive my ignorance, but what is the maximum installed capacity for
wind power in the UK ATM, and shouldn't the scale be set to that
value?

Why? you never SEE that much.

Its about 3,8GW of actual metered stuff.

BM reports says weirdly that the forecast is for 3742, but there is
actually only 3731 installed (metered)!!

There's about another 2GW of rip off embedded paid 'on spec' on a guess
as to what it generates.

Of course it never makes the peak, because the grid cant handle it, and
half the time the windmills have to be feathered as well in strong winds..

Still its a day for the wind lobby to grab onto.. I think its well over
a year since they claimed 'wind supplied 10% of all our electricity'
(for nearly ten minutes at 5 a.m.)

I assume this is how the maxima on the other scales are set.

They are set by sheer 'what's the highest conceivable value'

Before the London sodding array came on board 3GW was an absurd scale..




And while I'm asking questions, what's the significance of the red and
orange segments on the coal, nuclear and ccgt dials?

Very little. They looked pretty.

The theory is they are putative danger points.



Also, I see the
French, Dutch and Irish ICT scales go from -ve to +ve, presumably
depending on which way the power is going. Would I be right in
assuming that -ve values refer to power being exported from the UK,
and +ve values to imported power?

Yes.



The irish ICT has been ****ed for months, the french has been at 1GW
most of the summer, touched 2GW briefly but is back to 1.5GW..I guess
that's inverter modules or something.

Torness was told to get off the grid due to grid problems..not sure if
its back on..the whole network is a bloody mess at the moment.

Thank god we have coal.

Martin Brown wrote:
On 24/11/2011 11:58, Mike Tomlinson wrote:

I seem to remember someone posted here about a "virtual host" error when
trying to access gridwatch.templar but can't find the post.

I have the same thing on Firefox 8.0 running on Linux (Fedora 15); the
error "Virtual host not found on this server" appears, yet Firefox 8.0
running in an XP virtual host on the same box works.

Not whinging, just odd behaviour.

Seems to work OK here. BTW Wind power output is pegged to the endstop at
3.1GW and has been since 10am this morning. Maybe fsd should be 5.0GW


I fixed the addresses so most typos work...

DNS may take time to propagate tho
Regards,
Martin Brown

On 24/11/2011 17:56, The Natural Philosopher wrote:
Martin Brown wrote:

Seems to work OK here. BTW Wind power output is pegged to the endstop
at 3.1GW and has been since 10am this morning. Maybe fsd should be 5.0GW

the meter won't get damaged from a very short and *very* occasional
overload :-)

Smiths industries knew how to make things that would last.
PS. I hope there is no radium on the dial pointers. :-)

Regards,
Martin Brown

Martin Brown wrote:
On 24/11/2011 17:56, The Natural Philosopher wrote:
Martin Brown wrote:

Seems to work OK here. BTW Wind power output is pegged to the endstop
at 3.1GW and has been since 10am this morning. Maybe fsd should be 5.0GW

the meter won't get damaged from a very short and *very* occasional
overload :-)

Smiths industries knew how to make things that would last.
PS. I hope there is no radium on the dial pointers. :-)

Smiths industries have just supplied me with a 3.5GW meter.
Now installed.
There's lots of radium in the dials.


I believe in hormesis ;-)


Regards,
Martin Brown

En el artículo , The Natural Philosopher
escribió:

The irish ICT has been ****ed for months

what's wrong with it?

, the french has been at 1GW
most of the summer,

Thought they were well provided for with nukes.

--
(\_/)
(='.'=)
(")_(")

Mike Tomlinson wrote:
En el artÃ*culo , The Natural Philosopher
escribió:

The irish ICT has been ****ed for months

what's wrong with it?

Its busted.

Agh

"Work is continuing to repair the fault on the Moyle Interconnector
south cable. Following protracted de-trenching operations, the cable has
been cut and one of the ends recovered onto the repair vessel for fault
location testing.

Up to this point, the impact on the repair programme of environmental
factors has been greater than expected. Overall delays to the original
programme of approximately 10 days have been experienced to date. It is
hoped that a revised expected return to service date will be known in
the coming days, taking into account the impact of now known
environmental factors on the remaining work."

That was 9 days ago..

, the french has been at 1GW
most of the summer,

Thought they were well provided for with nukes.

yebbut all that goes to italy, germany and spain.

Who don't want the nasty things on their soil.

En el artÃ*culo , The Natural Philosopher
escribió:

Following protracted de-trenching operations, the cable has
been cut and one of the ends recovered onto the repair vessel for fault
location testing.

Probably nicked by copper thieves in scuba kit...

"On 26th June 2011 at 0417 a fault was recorded on one of two 250 MW
cables that comprises the Moyle electricity interconnector, which
connects the electricity systems of Northern Ireland and Scotland. As a
result, the Interconnectors capacity for the transfer of electricity
between Scotland and Northern Ireland has been halved. The fault has
been confirmed as a short circuit between the integrated return
conductor and earth. Testing has shown the fault to be located offshore,
approximately 17km from the Northern Ireland shoreline in a water depth
of 140m."

"Due to the nature of working offshore, a typical repair schedule for
this type of fault could be in the region of six months."

Wonder if they used something similar to TDR to locate the fault?

To lose one 450MW cable could be regarded as unfortunate, to lose two
looks like carelessness. :-)

--
(\_/)
(='.'=)
(")_(")

Mike Tomlinson wrote:
En el artÃ*culo , The Natural Philosopher
escribió:

Following protracted de-trenching operations, the cable has
been cut and one of the ends recovered onto the repair vessel for fault
location testing.

Probably nicked by copper thieves in scuba kit...

"On 26th June 2011 at 0417 a fault was recorded on one of two 250 MW
cables that comprises the Moyle electricity interconnector, which
connects the electricity systems of Northern Ireland and Scotland. As a
result, the Interconnectors capacity for the transfer of electricity
between Scotland and Northern Ireland has been halved. The fault has
been confirmed as a short circuit between the integrated return
conductor and earth. Testing has shown the fault to be located offshore,
approximately 17km from the Northern Ireland shoreline in a water depth
of 140m."

"Due to the nature of working offshore, a typical repair schedule for
this type of fault could be in the region of six months."

Wonder if they used something similar to TDR to locate the fault?

To lose one 450MW cable could be regarded as unfortunate, to lose two
looks like carelessness. :-)

Nah. They bought the cable at B & Q - Oirish cheapskates.

On 24/11/2011 18:26, The Natural Philosopher wrote:
Martin Brown wrote:
On 24/11/2011 17:56, The Natural Philosopher wrote:
Martin Brown wrote:

Seems to work OK here. BTW Wind power output is pegged to the endstop
at 3.1GW and has been since 10am this morning. Maybe fsd should be
5.0GW

the meter won't get damaged from a very short and *very* occasional
overload :-)

Smiths industries knew how to make things that would last.
PS. I hope there is no radium on the dial pointers. :-)

Smiths industries have just supplied me with a 3.5GW meter.
Now installed.
There's lots of radium in the dials.


I believe in hormesis ;-)

:-)
I have held a piece of Trinitite glass (long after the event).

While I have your attention is there any chance of doing a more detailed
probe to determine the proportion of wind turbines that are actually
generating against the official total installed capacity.

I am convinced that some near me I pass regularly where 2 out of 3 are
feathered most days are installed to farm renewable grants rather than
wind and it would be very interesting to see. Even the best windfarms
seem to have at least 10% of turbines feathered at any one time.

I suspect certain wind farm players are not to put too fine a point on
it corrupt or at the very least gaming the system. Visibility of this
charade would do wonders for encouraging wind farms only to be built in
locations where the average wind speed is high enough to be worthwhile.

--
Regards,
Martin Brown

"The Natural Philosopher" wrote in message
...
Chris Hogg wrote:
On Thu, 24 Nov 2011 16:14:52 +0000, Martin Brown
wrote:

On 24/11/2011 11:58, Mike Tomlinson wrote:
I seem to remember someone posted here about a "virtual host" error
when
trying to access gridwatch.templar but can't find the post.

I have the same thing on Firefox 8.0 running on Linux (Fedora 15); the
error "Virtual host not found on this server" appears, yet Firefox 8.0
running in an XP virtual host on the same box works.

Not whinging, just odd behaviour.

Seems to work OK here. BTW Wind power output is pegged to the endstop at
3.1GW and has been since 10am this morning. Maybe fsd should be 5.0GW

Regards,
Martin Brown

Forgive my ignorance, but what is the maximum installed capacity for
wind power in the UK ATM, and shouldn't the scale be set to that
value?

Why? you never SEE that much.

Its about 3,8GW of actual metered stuff.

BM reports says weirdly that the forecast is for 3742, but there is
actually only 3731 installed (metered)!!

There's about another 2GW of rip off embedded paid 'on spec' on a guess as
to what it generates.

Of course it never makes the peak, because the grid cant handle it, and
half the time the windmills have to be feathered as well in strong winds..

snip

Interesting.
I happen to know someone who might have an insight into all this and I will
ask, but you seem to be saying that the wind farms are not built with enough
big wires to feed maximum load into the grid (or if not, inbound of the
connection point the grid cannot cope).

Intriguing design approach, if true :-(


--
No plan survives contact with the enemy.
[Not even bunny]

Helmuth von Moltke the Elder

(\__/)
(='.'=)
(")_(")

David WE Roberts wrote:

you seem to be saying that the wind farms are not built
with enough big wires to feed maximum load into the grid (or if not,
inbound of the connection point the grid cannot cope).
Intriguing design approach, if true :-(

Perhaps more a case that when the wind blows the owners of the windmills
are keen to sell their expensive electrons, but the grid has mostly
contracted in advance to buy cheaper predictable electrons from elsewhere?

Do the windfarms have contracts that force the grid to buy* their
output, similar to solar PV?



* or compensate them for not buying it.

Martin Brown wrote:
On 24/11/2011 18:26, The Natural Philosopher wrote:
Martin Brown wrote:
On 24/11/2011 17:56, The Natural Philosopher wrote:
Martin Brown wrote:

Seems to work OK here. BTW Wind power output is pegged to the endstop
at 3.1GW and has been since 10am this morning. Maybe fsd should be
5.0GW

the meter won't get damaged from a very short and *very* occasional
overload :-)

Smiths industries knew how to make things that would last.
PS. I hope there is no radium on the dial pointers. :-)

Smiths industries have just supplied me with a 3.5GW meter.
Now installed.
There's lots of radium in the dials.


I believe in hormesis ;-)

:-)
I have held a piece of Trinitite glass (long after the event).

While I have your attention is there any chance of doing a more detailed
probe to determine the proportion of wind turbines that are actually
generating against the official total installed capacity.

I am convinced that some near me I pass regularly where 2 out of 3 are
feathered most days are installed to farm renewable grants rather than
wind and it would be very interesting to see. Even the best windfarms
seem to have at least 10% of turbines feathered at any one time.

I suspect certain wind farm players are not to put too fine a point on
it corrupt or at the very least gaming the system. Visibility of this
charade would do wonders for encouraging wind farms only to be built in
locations where the average wind speed is high enough to be worthwhile.

you find the web site, and I will scrape the data.

I have found that there is almost zero real hard data online about
almost anything.

The internet is full of opinions, and spin, but appalingly low actual
real hard facts.

Despite the fact that the world is littered with sensors.

Its a shame, because sites that would do things like showing you how
high the river down the road is, or where all the trains actually are,
at any given moment, could be unbelievably useful.


I wondered about a sort of 'you have data, post it here' sort of site..

so all the people with e.g. home weather stations could post a location
and data, and one could build a map..

But then I realised all the AGW tools would simply add 5 degrees and troll..

On 25/11/2011 10:42, The Natural Philosopher wrote:
Martin Brown wrote:

While I have your attention is there any chance of doing a more
detailed probe to determine the proportion of wind turbines that are
actually generating against the official total installed capacity.

I am convinced that some near me I pass regularly where 2 out of 3 are
feathered most days are installed to farm renewable grants rather than
wind and it would be very interesting to see. Even the best windfarms
seem to have at least 10% of turbines feathered at any one time.


you find the web site, and I will scrape the data.

Don't hold your breath but I will see if I can find anything useful.

I have found that there is almost zero real hard data online about
almost anything.

Astronomy and HEP is actually quite well catered for. The Web was
actually put together to allow CERN to share data on the Internet. We
used JANET to move some astronomy data around long before that. You
could be very unpopular for moving big files (big then was small today).

The internet is full of opinions, and spin, but appalingly low actual
real hard facts.

Despite the fact that the world is littered with sensors.

Its a shame, because sites that would do things like showing you how
high the river down the road is, or where all the trains actually are,
at any given moment, could be unbelievably useful.

Realtime RTC info on route maps is pretty useful and available now.

I wondered about a sort of 'you have data, post it here' sort of site..

so all the people with e.g. home weather stations could post a location
and data, and one could build a map..

But then I realised all the AGW tools would simply add 5 degrees and
troll..

Careful. AGW is real enough even if the enviros and greens overplay it.
The really bad guys are the deniers for hire that work for various US
ultra-right wing "think tanks" and have previous for doing big tobaccos
dirty work by convincing people to keep smoking. They use the same
disinformation and smear tactics against AGW and climate researchers.

--
Regards,
Martin Brown

Andy Burns wrote:
David WE Roberts wrote:

you seem to be saying that the wind farms are not built
with enough big wires to feed maximum load into the grid (or if not,
inbound of the connection point the grid cannot cope).
Intriguing design approach, if true :-(

Perhaps more a case that when the wind blows the owners of the windmills
are keen to sell their expensive electrons, but the grid has mostly
contracted in advance to buy cheaper predictable electrons from elsewhere?

Do the windfarms have contracts that force the grid to buy* their
output, similar to solar PV?



yes.

If te grid cant take it, they get paid copmpensation.


* or compensate them for not buying it.

yes.

Martin Brown wrote:
On 25/11/2011 10:42, The Natural Philosopher wrote:
Martin Brown wrote:

While I have your attention is there any chance of doing a more
detailed probe to determine the proportion of wind turbines that are
actually generating against the official total installed capacity.

I am convinced that some near me I pass regularly where 2 out of 3 are
feathered most days are installed to farm renewable grants rather than
wind and it would be very interesting to see. Even the best windfarms
seem to have at least 10% of turbines feathered at any one time.


you find the web site, and I will scrape the data.

Don't hold your breath but I will see if I can find anything useful.

I have found that there is almost zero real hard data online about
almost anything.

Astronomy and HEP is actually quite well catered for. The Web was
actually put together to allow CERN to share data on the Internet. We
used JANET to move some astronomy data around long before that. You
could be very unpopular for moving big files (big then was small today).

The internet is full of opinions, and spin, but appalingly low actual
real hard facts.

Despite the fact that the world is littered with sensors.

Its a shame, because sites that would do things like showing you how
high the river down the road is, or where all the trains actually are,
at any given moment, could be unbelievably useful.

Realtime RTC info on route maps is pretty useful and available now.


Yes, thats the one area where it works properly.

I wondered about a sort of 'you have data, post it here' sort of site..

so all the people with e.g. home weather stations could post a location
and data, and one could build a map..

But then I realised all the AGW tools would simply add 5 degrees and
troll..

Careful. AGW is real enough even if the enviros and greens overplay it.
The really bad guys are the deniers for hire that work for various US
ultra-right wing "think tanks" and have previous for doing big tobaccos
dirty work by convincing people to keep smoking. They use the same
disinformation and smear tactics against AGW and climate researchers.

Its not a question of denying it, its a question of denying the magnitude.

Obviously CO2 does something: the question is what?, and how much?

If you take out the fudge factors that are built in to make it fit the
curves (that are increasingly being challenged in their validity) the
answer would seem to be:

'it warms things up, but not by a noticeable amount: Other things, some
of which we don't really understand, make a far larger impact'

If you take out the fudge factor its about 0.25 C over the next century.
Hardly worth wrecking the world's economy for.

http://www.clarewind.org.uk/events-1.php?event=32

is worth a glance to summarise some of the other possibilities.

On 25/11/2011 11:23, The Natural Philosopher wrote:

snip

This leads to a basic principle that can be expressed thus:

"Costs are proportional to the set of the worst cases. Earnings are
proportional to the average case."

This has a huge impact in terms of renewable generation from
intermittent sources. Basically the engineering has to be able to absorb
the peak generator output (or the source must be throttled back and the
energy discarded) BUT the income is calculated ion the average power
output - in the case of wind that's a 4:1 difference. Or more. That is
on average the size of the generator and link wires is 4 times greater
than on average, it needs to be.

Irrelevant for domestic PV installations. 4KW is well below the load
that even the meanest domestic connection will supply so no additional
infrastructure is required.

It gets worse. The backup likewise has to be as good as the worst case
wind output. One of the things that has become established over the last
year or two is that national wind output can, on occasion, drop to as
near zero as makes no difference.

Solar PV is even worse. It's guaranteed to do this every night.

Solar PV doesn't really need any hot reserve, let alone spinning
reserve. With a multitude of very small generators over an extended area
the actual output could be predicted to very close limits merely on the
basis of cloud cover and date.

Solar PV may do little to help with the 5.30 pm peak but almost all of
its output (all for most of the year) will fall within the high demand
zone during the day unlike the output of windmills which is much less
predicable and close to random in distribution through 24 hours.

snip

--
Roger Chapman

Roger Chapman wrote:
On 25/11/2011 11:23, The Natural Philosopher wrote:

snip

This leads to a basic principle that can be expressed thus:

"Costs are proportional to the set of the worst cases. Earnings are
proportional to the average case."

This has a huge impact in terms of renewable generation from
intermittent sources. Basically the engineering has to be able to absorb
the peak generator output (or the source must be throttled back and the
energy discarded) BUT the income is calculated ion the average power
output - in the case of wind that's a 4:1 difference. Or more. That is
on average the size of the generator and link wires is 4 times greater
than on average, it needs to be.

Irrelevant for domestic PV installations. 4KW is well below the load
that even the meanest domestic connection will supply so no additional
infrastructure is required.

It gets worse. The backup likewise has to be as good as the worst case
wind output. One of the things that has become established over the last
year or two is that national wind output can, on occasion, drop to as
near zero as makes no difference.

Solar PV is even worse. It's guaranteed to do this every night.

Solar PV doesn't really need any hot reserve, let alone spinning
reserve. With a multitude of very small generators over an extended area
the actual output could be predicted to very close limits merely on the
basis of cloud cover and date.


it doesn't matter.

You STILL have to ramp up gas to cope at sunset, and that gas needs to
be warmed up on the way, and while it ramps up, its wasting gas, and
when it ramps down, its losing stored heat.

It makes **** all difference if you KNOW what variation you have in
advance - you still have to DEAL with it.


Solar PV may do little to help with the 5.30 pm peak but almost all of
its output (all for most of the year) will fall within the high demand
zone during the day unlike the output of windmills which is much less
predicable and close to random in distribution through 24 hours.


Wrong again, the forecasts are accurate to 70% typically.

It is not the unpredictability of intermittency that is the problem its
the variation, and, in particular, the slew rate.



snip

On 25/11/2011 12:45, The Natural Philosopher wrote:

snip

This leads to a basic principle that can be expressed thus:

"Costs are proportional to the set of the worst cases. Earnings are
proportional to the average case."

This has a huge impact in terms of renewable generation from
intermittent sources. Basically the engineering has to be able to absorb
the peak generator output (or the source must be throttled back and the
energy discarded) BUT the income is calculated ion the average power
output - in the case of wind that's a 4:1 difference. Or more. That is
on average the size of the generator and link wires is 4 times greater
than on average, it needs to be.

Irrelevant for domestic PV installations. 4KW is well below the load
that even the meanest domestic connection will supply so no additional
infrastructure is required.

It gets worse. The backup likewise has to be as good as the worst case
wind output. One of the things that has become established over the last
year or two is that national wind output can, on occasion, drop to as
near zero as makes no difference.

Solar PV is even worse. It's guaranteed to do this every night.

Solar PV doesn't really need any hot reserve, let alone spinning
reserve. With a multitude of very small generators over an extended
area the actual output could be predicted to very close limits merely
on the basis of cloud cover and date.


it doesn't matter.

You STILL have to ramp up gas to cope at sunset, and that gas needs to
be warmed up on the way, and while it ramps up, its wasting gas, and
when it ramps down, its losing stored heat.

Reading the above paragraph a stranger to this argument could easily
believe that a) PV goes from full output to zero in an instant and b)
that demand is at a constant level 24/7. For some of the year at least
declining output from PV would parallel declining demand lessening the
need for intervention.

It makes **** all difference if you KNOW what variation you have in
advance - you still have to DEAL with it.

Now what was that difference you were describing not so long ago - oh
yes, the difference between hot reserve and spinning reserve. Knowing
more accurately what is to come should make a difference.

Solar PV may do little to help with the 5.30 pm peak but almost all of
its output (all for most of the year) will fall within the high demand
zone during the day unlike the output of windmills which is much less
predicable and close to random in distribution through 24 hours.


Wrong again, the forecasts are accurate to 70% typically.

Accuracy on which particular factors?

And I see that you at least think that maximum wind power at the time of
minimum demand is not a problem.

It is not the unpredictability of intermittency that is the problem its
the variation, and, in particular, the slew rate.

I am tempted to say what has that got to do with the price of fish.
Without cloud cover the rise of solar power from early daylight to solar
noon with be slow and smooth with the decline after noon likewise. Cloud
cover will have an effect but with the PV generation widespread the rate
of change due to changes in cloud cover will be small.

snip



--
Roger Chapman

On 25/11/2011 11:23, The Natural Philosopher wrote:
When designing a machine, (or indeed a piece of software), a very high
proportion of the cost and indeed materials, goes into meeting worst
case event handling:

Indeed. When I used to design software professionally I estimated that
at least 90% of the program was there to protect the system from the
user and only 5% - 10% did anything useful (though woe betide you if you
omitted the 90%). In addition, it was pointless to optimise the code
since, once again 90% of the time was spent inside the operating system
and you were at the mercy of IBM, ICL et al.

Another Dave

On 25/11/2011 12:45, The Natural Philosopher wrote:
Roger Chapman wrote:
On 25/11/2011 11:23, The Natural Philosopher wrote:

It gets worse. The backup likewise has to be as good as the worst case
wind output. One of the things that has become established over the last
year or two is that national wind output can, on occasion, drop to as
near zero as makes no difference.

If we are becalmed in a winter blocking high and also very cold which
causes high demand for heating too. Last year was a good example. You
basically have to provide enough other capacity to handle that worst
case scenario or drop people off the grid in rolling blackouts.

Solar PV is even worse. It's guaranteed to do this every night.

Solar PV doesn't really need any hot reserve, let alone spinning
reserve. With a multitude of very small generators over an extended
area the actual output could be predicted to very close limits merely
on the basis of cloud cover and date.

it doesn't matter.

You STILL have to ramp up gas to cope at sunset, and that gas needs to
be warmed up on the way, and while it ramps up, its wasting gas, and
when it ramps down, its losing stored heat.

Actually I don't think you do - at least not with the amount of solar
power that is installed in the UK at present. The load demand curve is
on the decline by sunset anyway except perhaps in the far north and deep
midwinter so as long as the amount of solar dropping off is less that
the amount of load being shed it acts to smooth things out.

It makes **** all difference if you KNOW what variation you have in
advance - you still have to DEAL with it.

If you know that both load and generation are going to go down it is a
lot more helpful than if they are anti-correlated.

That is the reason why at lower latitudes solar PV can make a lot more
sense (though solar hot water is better) - peak demand there for AC is
strongly correlated with sunshine and having an array on the roof helps
decrease inbound radiative heat load. A win win situation. I have to say
it is madness subsidising them in the UK and Germany.

Solar PV may do little to help with the 5.30 pm peak but almost all of
its output (all for most of the year) will fall within the high demand
zone during the day unlike the output of windmills which is much less
predicable and close to random in distribution through 24 hours.


Wrong again, the forecasts are accurate to 70% typically.

It is not the unpredictability of intermittency that is the problem its
the variation, and, in particular, the slew rate.

The slew rate on solar will be fairly soft since unless they are
tracking arrays they taper off at a predictable rate at sunset. And peak
demand is during daytime so they are positive load correlated. Their
total output is a useless fraction of load barely worth the effort of
measuring but that is a different matter entirely.

--
Regards,
Martin Brown

On 25/11/2011 11:38, The Natural Philosopher wrote:
Martin Brown wrote:
On 25/11/2011 10:42, The Natural Philosopher wrote:

But then I realised all the AGW tools would simply add 5 degrees and
troll..

Careful. AGW is real enough even if the enviros and greens overplay
it. The really bad guys are the deniers for hire that work for various
US ultra-right wing "think tanks" and have previous for doing big
tobaccos dirty work by convincing people to keep smoking. They use the
same disinformation and smear tactics against AGW and climate
researchers.

Its not a question of denying it, its a question of denying the magnitude.

There are far too many deniers for hire paid to mislead the public.
Exxon has been sponsoring a fair number of players to spread massive
amounts of disinformation to the public. Bad enough that the Royal
Society got annoyed enough to write them an open letter to cease and
desist funding deliberate misrepresentation of the science.


Obviously CO2 does something: the question is what?, and how much?

Agreed. On this I prefer looking at model fits on the available data and
it looks pretty much like the recent GHG forcings have been of the order
of 1K/century (but with most of it in the last fifty years) with various
periodic terms and annual noise thrown in to make spotting the trends
harder. Atmospheric CO2 continues to rise at an ever increasing rate
from fossil fuels - sooner or later it will get to the point where
permafrost melting will cause a sudden positive feedback.

Since you are clearly good at data mining try passing HADCRUT or the new
longer global temperature time series though a low pass filter with a
sharp 11 year high frequency cutoff (11 year boxcar will do). This zaps
any solar sunspot cycle contributions and most of the inter annual
noise. I think you will be surprised with what is left. I was.

If you take out the fudge factors that are built in to make it fit the
curves (that are increasingly being challenged in their validity) the
answer would seem to be:

'it warms things up, but not by a noticeable amount: Other things, some
of which we don't really understand, make a far larger impact'

If you take out the fudge factor its about 0.25 C over the next century.

It is more likely to be around 2K but could be higher.

Hardly worth wrecking the world's economy for.

No. We have merchant bankers to do that for us by trading worthless
pieces of digital paper and then demanding massive taxpayer bailouts. So
long as they get their *BIG* bonuses they do not care.

At least AGW mitigation would produce real engineering infrastructure
jobs if managed correctly. I don't favour anything beyond no regrets
energy saving measures at present of the sort that were last seen in the
OPEC induced oil crisis of the 1970's "Save It" campaign.

http://www.clarewind.org.uk/events-1.php?event=32

is worth a glance to summarise some of the other possibilities.

I am a physicist by training I have a pretty good idea how to sort the
wheat from the chaff. My position on this is roughly in line with BP.

--
Regards,
Martin Brown

Roger Chapman wrote:
On 25/11/2011 12:45, The Natural Philosopher wrote:

snip

This leads to a basic principle that can be expressed thus:

"Costs are proportional to the set of the worst cases. Earnings are
proportional to the average case."

This has a huge impact in terms of renewable generation from
intermittent sources. Basically the engineering has to be able to
absorb
the peak generator output (or the source must be throttled back and the
energy discarded) BUT the income is calculated ion the average power
output - in the case of wind that's a 4:1 difference. Or more. That is
on average the size of the generator and link wires is 4 times greater
than on average, it needs to be.

Irrelevant for domestic PV installations. 4KW is well below the load
that even the meanest domestic connection will supply so no additional
infrastructure is required.

It gets worse. The backup likewise has to be as good as the worst case
wind output. One of the things that has become established over the
last
year or two is that national wind output can, on occasion, drop to as
near zero as makes no difference.

Solar PV is even worse. It's guaranteed to do this every night.

Solar PV doesn't really need any hot reserve, let alone spinning
reserve. With a multitude of very small generators over an extended
area the actual output could be predicted to very close limits merely
on the basis of cloud cover and date.


it doesn't matter.

You STILL have to ramp up gas to cope at sunset, and that gas needs to
be warmed up on the way, and while it ramps up, its wasting gas, and
when it ramps down, its losing stored heat.

Reading the above paragraph a stranger to this argument could easily
believe that a) PV goes from full output to zero in an instant and b)
that demand is at a constant level 24/7. For some of the year at least
declining output from PV would parallel declining demand lessening the
need for intervention.

It makes **** all difference if you KNOW what variation you have in
advance - you still have to DEAL with it.

Now what was that difference you were describing not so long ago - oh
yes, the difference between hot reserve and spinning reserve. Knowing
more accurately what is to come should make a difference.


Only in your mind.

You still have to put your foot on the accelerator to get up the hill
whether you know about it in advance or not.

Solar PV may do little to help with the 5.30 pm peak but almost all of
its output (all for most of the year) will fall within the high demand
zone during the day unlike the output of windmills which is much less
predicable and close to random in distribution through 24 hours.


Wrong again, the forecasts are accurate to 70% typically.

Accuracy on which particular factors?

power output over time.

And I see that you at least think that maximum wind power at the time of
minimum demand is not a problem.

at the moment its relatively pathetic so it isn't.


It is not the unpredictability of intermittency that is the problem its
the variation, and, in particular, the slew rate.

I am tempted to say what has that got to do with the price of fish.
Without cloud cover the rise of solar power from early daylight to solar
noon with be slow and smooth with the decline after noon likewise. Cloud
cover will have an effect but with the PV generation widespread the rate
of change due to changes in cloud cover will be small.


Bull****

clouds reduce power from a solar panel by 4-10 times.

Clouds are not amenable to prediction.

And none of it matters: all it does is reduce the amount of spinning
reserve you need. Hot standby still needs to be cued in for diurnal
valuations.



snip

Martin Brown wrote:
On 25/11/2011 12:45, The Natural Philosopher wrote:
Roger Chapman wrote:
On 25/11/2011 11:23, The Natural Philosopher wrote:

It gets worse. The backup likewise has to be as good as the worst case
wind output. One of the things that has become established over the
last
year or two is that national wind output can, on occasion, drop to as
near zero as makes no difference.

If we are becalmed in a winter blocking high and also very cold which
causes high demand for heating too. Last year was a good example. You
basically have to provide enough other capacity to handle that worst
case scenario or drop people off the grid in rolling blackouts.

Solar PV is even worse. It's guaranteed to do this every night.

Solar PV doesn't really need any hot reserve, let alone spinning
reserve. With a multitude of very small generators over an extended
area the actual output could be predicted to very close limits merely
on the basis of cloud cover and date.

it doesn't matter.

You STILL have to ramp up gas to cope at sunset, and that gas needs to
be warmed up on the way, and while it ramps up, its wasting gas, and
when it ramps down, its losing stored heat.

Actually I don't think you do - at least not with the amount of solar
power that is installed in the UK at present. The load demand curve is
on the decline by sunset anyway except perhaps in the far north and deep
midwinter so as long as the amount of solar dropping off is less that
the amount of load being shed it acts to smooth things out.

It is accepted that the huge sums spent on solar power have achieved
approximately zero impact on anything except consumer prices.


It makes **** all difference if you KNOW what variation you have in
advance - you still have to DEAL with it.

If you know that both load and generation are going to go down it is a
lot more helpful than if they are anti-correlated.

shame that demand peaks just after dark then isn't it?

That is the reason why at lower latitudes solar PV can make a lot more
sense (though solar hot water is better) - peak demand there for AC is
strongly correlated with sunshine and having an array on the roof helps
decrease inbound radiative heat load. A win win situation. I have to say
it is madness subsidising them in the UK and Germany.

you can do a LOT better in those climates by building in thermal mass.
typically the higher temperatures are in dry desert climates. The night
time temperatures are surprisingly low.


Solar PV may do little to help with the 5.30 pm peak but almost all of
its output (all for most of the year) will fall within the high demand
zone during the day unlike the output of windmills which is much less
predicable and close to random in distribution through 24 hours.


Wrong again, the forecasts are accurate to 70% typically.

It is not the unpredictability of intermittency that is the problem its
the variation, and, in particular, the slew rate.

The slew rate on solar will be fairly soft since unless they are
tracking arrays they taper off at a predictable rate at sunset. And peak
demand is during daytime so they are positive load correlated. Their
total output is a useless fraction of load barely worth the effort of
measuring but that is a different matter entirely.

They taper off a lot faster than that if - for example - convection
cloud builds rapidly.

But it doesn't matter..you can ramp up CCGT in about an hour. If you
have 5 hours to get 5GW up you need to get cracking and start the lot.

If the sun goes behind clouds nationally - and it can - you need to have
5GW spinning reserve.

Martin Brown wrote:
On 25/11/2011 11:38, The Natural Philosopher wrote:
Martin Brown wrote:
On 25/11/2011 10:42, The Natural Philosopher wrote:

But then I realised all the AGW tools would simply add 5 degrees and
troll..

Careful. AGW is real enough even if the enviros and greens overplay
it. The really bad guys are the deniers for hire that work for various
US ultra-right wing "think tanks" and have previous for doing big
tobaccos dirty work by convincing people to keep smoking. They use the
same disinformation and smear tactics against AGW and climate
researchers.

Its not a question of denying it, its a question of denying the
magnitude.

There are far too many deniers for hire paid to mislead the public.
Exxon has been sponsoring a fair number of players to spread massive
amounts of disinformation to the public. Bad enough that the Royal
Society got annoyed enough to write them an open letter to cease and
desist funding deliberate misrepresentation of the science.


Obviously CO2 does something: the question is what?, and how much?

Agreed. On this I prefer looking at model fits on the available data and
it looks pretty much like the recent GHG forcings have been of the order
of 1K/century (but with most of it in the last fifty years) with various
periodic terms and annual noise thrown in to make spotting the trends
harder. Atmospheric CO2 continues to rise at an ever increasing rate
from fossil fuels - sooner or later it will get to the point where
permafrost melting will cause a sudden positive feedback.

No it wont. Thats an assumption.


Since you are clearly good at data mining try passing HADCRUT or the new
longer global temperature time series though a low pass filter with a
sharp 11 year high frequency cutoff (11 year boxcar will do). This zaps
any solar sunspot cycle contributions and most of the inter annual
noise. I think you will be surprised with what is left. I was.

If you take out the fudge factors that are built in to make it fit the
curves (that are increasingly being challenged in their validity) the
answer would seem to be:

'it warms things up, but not by a noticeable amount: Other things, some
of which we don't really understand, make a far larger impact'

If you take out the fudge factor its about 0.25 C over the next century.

It is more likely to be around 2K but could be higher.


No. I said IF YOU TAKE OUT THE FUDGE FACTOR.

The WHOLE IPCC positions relies on the ASSUMPTION that any temperature
rise we cant account for MUST be accounted for by CO2 AND by 'positive
feedback factors' .

No one knows what these are, what value to place on them or wherther
they even exist.

The more the studies come out, the more they seem to NOT exist.

Vis the latest offering in 'Ccience' (Climate Sensitivity Estimated from
Temperature Reconstructions of the Last Glacial Maximum)


where they estimate that IF the sensitivity to CO2 was what the IPCC
says it is, the whole world would have frozen solid in the last ice age.
Oddly, it did not.

They are coming out with far lower temperature rises due to AGW. There
main conclusion is that its 'unlikely to be serious'



Hardly worth wrecking the world's economy for.

No. We have merchant bankers to do that for us by trading worthless
pieces of digital paper and then demanding massive taxpayer bailouts. So
long as they get their *BIG* bonuses they do not care.

At least AGW mitigation would produce real engineering infrastructure
jobs if managed correctly.

But it won't be, because its being managed by governments and lobby groups

I don't favour anything beyond no regrets
energy saving measures at present of the sort that were last seen in the
OPEC induced oil crisis of the 1970's "Save It" campaign.

http://www.clarewind.org.uk/events-1.php?event=32

is worth a glance to summarise some of the other possibilities.

I am a physicist by training I have a pretty good idea how to sort the
wheat from the chaff. My position on this is roughly in line with BP.

BP?

On 25/11/2011 15:59, The Natural Philosopher wrote:

snip

This leads to a basic principle that can be expressed thus:

"Costs are proportional to the set of the worst cases. Earnings are
proportional to the average case."

This has a huge impact in terms of renewable generation from
intermittent sources. Basically the engineering has to be able to
absorb
the peak generator output (or the source must be throttled back and
the
energy discarded) BUT the income is calculated ion the average power
output - in the case of wind that's a 4:1 difference. Or more. That is
on average the size of the generator and link wires is 4 times greater
than on average, it needs to be.

Irrelevant for domestic PV installations. 4KW is well below the load
that even the meanest domestic connection will supply so no additional
infrastructure is required.

It gets worse. The backup likewise has to be as good as the worst case
wind output. One of the things that has become established over the
last
year or two is that national wind output can, on occasion, drop to as
near zero as makes no difference.

Solar PV is even worse. It's guaranteed to do this every night.

Solar PV doesn't really need any hot reserve, let alone spinning
reserve. With a multitude of very small generators over an extended
area the actual output could be predicted to very close limits merely
on the basis of cloud cover and date.


it doesn't matter.

You STILL have to ramp up gas to cope at sunset, and that gas needs to
be warmed up on the way, and while it ramps up, its wasting gas, and
when it ramps down, its losing stored heat.

Reading the above paragraph a stranger to this argument could easily
believe that a) PV goes from full output to zero in an instant and b)
that demand is at a constant level 24/7. For some of the year at least
declining output from PV would parallel declining demand lessening the
need for intervention.

It makes **** all difference if you KNOW what variation you have in
advance - you still have to DEAL with it.

Now what was that difference you were describing not so long ago - oh
yes, the difference between hot reserve and spinning reserve. Knowing
more accurately what is to come should make a difference.

Only in your mind.

Just because you are blind to the possibilities ...

You still have to put your foot on the accelerator to get up the hill
whether you know about it in advance or not.

But if you know there is no hill you don't need to plan for that
eventuality.

Solar PV may do little to help with the 5.30 pm peak but almost all of
its output (all for most of the year) will fall within the high demand
zone during the day unlike the output of windmills which is much less
predicable and close to random in distribution through 24 hours.


Wrong again, the forecasts are accurate to 70% typically.

Accuracy on which particular factors?

power output over time.

At what anticipation?

And I see that you at least think that maximum wind power at the time
of minimum demand is not a problem.

at the moment its relatively pathetic so it isn't.

You sure about that?

It is not the unpredictability of intermittency that is the problem its
the variation, and, in particular, the slew rate.

I am tempted to say what has that got to do with the price of fish.
Without cloud cover the rise of solar power from early daylight to
solar noon with be slow and smooth with the decline after noon
likewise. Cloud cover will have an effect but with the PV generation
widespread the rate of change due to changes in cloud cover will be
small.


Bull****

You have no real answer to that then.

clouds reduce power from a solar panel by 4-10 times.

Clouds are not amenable to prediction.

Cloud cover on a national scale is.

And none of it matters: all it does is reduce the amount of spinning
reserve you need. Hot standby still needs to be cued in for diurnal
valuations.

So a reduction in the need for spinning reserve is of no account then.

--
Roger Chapman

Roger Chapman wrote:
On 25/11/2011 15:59, The Natural Philosopher wrote:

snip

This leads to a basic principle that can be expressed thus:

"Costs are proportional to the set of the worst cases. Earnings are
proportional to the average case."

This has a huge impact in terms of renewable generation from
intermittent sources. Basically the engineering has to be able to
absorb
the peak generator output (or the source must be throttled back and
the
energy discarded) BUT the income is calculated ion the average power
output - in the case of wind that's a 4:1 difference. Or more.
That is
on average the size of the generator and link wires is 4 times
greater
than on average, it needs to be.

Irrelevant for domestic PV installations. 4KW is well below the load
that even the meanest domestic connection will supply so no additional
infrastructure is required.

It gets worse. The backup likewise has to be as good as the worst
case
wind output. One of the things that has become established over the
last
year or two is that national wind output can, on occasion, drop to as
near zero as makes no difference.

Solar PV is even worse. It's guaranteed to do this every night.

Solar PV doesn't really need any hot reserve, let alone spinning
reserve. With a multitude of very small generators over an extended
area the actual output could be predicted to very close limits merely
on the basis of cloud cover and date.


it doesn't matter.

You STILL have to ramp up gas to cope at sunset, and that gas needs to
be warmed up on the way, and while it ramps up, its wasting gas, and
when it ramps down, its losing stored heat.

Reading the above paragraph a stranger to this argument could easily
believe that a) PV goes from full output to zero in an instant and b)
that demand is at a constant level 24/7. For some of the year at least
declining output from PV would parallel declining demand lessening the
need for intervention.

It makes **** all difference if you KNOW what variation you have in
advance - you still have to DEAL with it.

Now what was that difference you were describing not so long ago - oh
yes, the difference between hot reserve and spinning reserve. Knowing
more accurately what is to come should make a difference.

Only in your mind.

Just because you are blind to the possibilities ...

You still have to put your foot on the accelerator to get up the hill
whether you know about it in advance or not.

But if you know there is no hill you don't need to plan for that
eventuality.


? what? so you are saing that as soon as you get to East Angleuia, you
are going to remove te 2 liter engiobne from your car and install a
200CC bike engine?

Get real.

You SEEM to be under a misapprehension that the power is wasted on
spinning reserve. That's not so. The power is wasted bringing warm or
cold kit up to power, and when it finally gets to cool down again, and
its lost when you are running a constant heat-loss heat engine
throttled back to less power them it normally delivers.

Whether you know in advance or not what its going to be makes zero
difference.


Solar PV may do little to help with the 5.30 pm peak but almost all of
its output (all for most of the year) will fall within the high demand
zone during the day unlike the output of windmills which is much less
predicable and close to random in distribution through 24 hours.


Wrong again, the forecasts are accurate to 70% typically.

Accuracy on which particular factors?

power output over time.

At what anticipation?

see BMreports wind outturn data.

And I see that you at least think that maximum wind power at the time
of minimum demand is not a problem.

at the moment its relatively pathetic so it isn't.

You sure about that?

Yes.

It is not the unpredictability of intermittency that is the problem its
the variation, and, in particular, the slew rate.

I am tempted to say what has that got to do with the price of fish.
Without cloud cover the rise of solar power from early daylight to
solar noon with be slow and smooth with the decline after noon
likewise. Cloud cover will have an effect but with the PV generation
widespread the rate of change due to changes in cloud cover will be
small.


Bull****

You have no real answer to that then.

clouds reduce power from a solar panel by 4-10 times.

Clouds are not amenable to prediction.

Cloud cover on a national scale is.


No it is not.

If you knew ANYTHING about meteorology you would know that the
occurrence and incidence of convection cloud is VERY difficult to predict.

But it isn't relevant. Knowing doesn't change the efficiency dynamics of
the needful backup.



And none of it matters: all it does is reduce the amount of spinning
reserve you need. Hot standby still needs to be cued in for diurnal
valuations.

So a reduction in the need for spinning reserve is of no account then.

Not really no. You need enough in any case to cope with unplanned
outages from any power sources.

Below that minimum which is currently well above wind and PV generation
needs you cannot go anyway safely.

On 25/11/2011 19:23, The Natural Philosopher wrote:

snip

Solar PV is even worse. It's guaranteed to do this every night.

Solar PV doesn't really need any hot reserve, let alone spinning
reserve. With a multitude of very small generators over an extended
area the actual output could be predicted to very close limits merely
on the basis of cloud cover and date.


it doesn't matter.

You STILL have to ramp up gas to cope at sunset, and that gas needs to
be warmed up on the way, and while it ramps up, its wasting gas, and
when it ramps down, its losing stored heat.

Reading the above paragraph a stranger to this argument could easily
believe that a) PV goes from full output to zero in an instant and b)
that demand is at a constant level 24/7. For some of the year at least
declining output from PV would parallel declining demand lessening the
need for intervention.

It makes **** all difference if you KNOW what variation you have in
advance - you still have to DEAL with it.

Now what was that difference you were describing not so long ago - oh
yes, the difference between hot reserve and spinning reserve. Knowing
more accurately what is to come should make a difference.

Only in your mind.

Just because you are blind to the possibilities ...

You still have to put your foot on the accelerator to get up the hill
whether you know about it in advance or not.

But if you know there is no hill you don't need to plan for that
eventuality.

? what? so you are saing that as soon as you get to East Angleuia, you
are going to remove te 2 liter engiobne from your car and install a
200CC bike engine?

Well if you will talk in riddles ...

Get real.

You SEEM to be under a misapprehension that the power is wasted on
spinning reserve. That's not so. The power is wasted bringing warm or
cold kit up to power, and when it finally gets to cool down again, and
its lost when you are running a constant heat-loss heat engine throttled
back to less power them it normally delivers.

Spinning reserve is a perpetual motion machine?

Whether you know in advance or not what its going to be makes zero
difference.

Solar PV may do little to help with the 5.30 pm peak but almost
all of
its output (all for most of the year) will fall within the high
demand
zone during the day unlike the output of windmills which is much less
predicable and close to random in distribution through 24 hours.


Wrong again, the forecasts are accurate to 70% typically.

Accuracy on which particular factors?

power output over time.

At what anticipation?

see BMreports wind outturn data.

When I last looked at that page I nearly died of boredom in the time it
took to load.

And I see that you at least think that maximum wind power at the time
of minimum demand is not a problem.

at the moment its relatively pathetic so it isn't.

You sure about that?

Yes.

So it doesn't cause the base load operators to operate at reduced
efficiency?

It is not the unpredictability of intermittency that is the problem
its
the variation, and, in particular, the slew rate.

I am tempted to say what has that got to do with the price of fish.
Without cloud cover the rise of solar power from early daylight to
solar noon with be slow and smooth with the decline after noon
likewise. Cloud cover will have an effect but with the PV generation
widespread the rate of change due to changes in cloud cover will be
small.


Bull****

You have no real answer to that then.

clouds reduce power from a solar panel by 4-10 times.

Clouds are not amenable to prediction.

Cloud cover on a national scale is.


No it is not.

If you knew ANYTHING about meteorology you would know that the
occurrence and incidence of convection cloud is VERY difficult to predict.

The weather forecasters don't seem to have any problem in predicting
mist or cloud cover.

But it isn't relevant. Knowing doesn't change the efficiency dynamics of
the needful backup.

I was under the impression that the point at issue was the
predictability of PV output.

And none of it matters: all it does is reduce the amount of spinning
reserve you need. Hot standby still needs to be cued in for diurnal
valuations.

So a reduction in the need for spinning reserve is of no account then.

Not really no. You need enough in any case to cope with unplanned
outages from any power sources.

But domestic PV is made up of a multitude of very small inputs. The
closest you will ever get to a major outage is a local breaker taking
out a district which will actually reduce demand on the grid rather than
add to it.

Below that minimum which is currently well above wind and PV generation
needs you cannot go anyway safely.

Could you please rephrase that in understandable English.

--
Roger Chapman

On Fri, 25 Nov 2011 12:33:33 +0000, Roger Chapman wrote:

Irrelevant for domestic PV installations. 4KW is well below the load
that even the meanest domestic connection will supply so no additional
infrastructure is required.

At the current low density of domestic PV systems but how many would
you need in a given area before the substation connected to them
became "undersized"?

Base load of an occupied house is around 1kW but these PV system have
peak output during the day when, generally speaking, homes are empty.
So most of that 4kW will be exported from each installation. Now if
the substation is sized on 1kW/home average once you get over 25% of
homes with PV systems there is potential for the substation to become
overloaded.

Not to mention what happens to the voltage in the area when all these
things are trying to export and that export disappears in seconds as
a clouds shadow moves across the neighbourhood.

--
Cheers
Dave.

unlike the output of windmills which is much less
predicable and close to random in distribution through 24 hours.

Damn. Can't find out who wrote that...

.... but. You'll find there is a diurnal pattern in the wind. It often
goes light around sunset, especially in areas where there's a sea breeze
powered by temperature difference between the land and the water.

Andy.

On 25 Nov,
Roger Chapman (and others) wrote:

And I see that you at least think that maximum wind power at the time
of minimum demand is not a problem.

at the moment its relatively pathetic so it isn't.

You sure about that?

It seems to have been around 50% of nuclear output for the last day or two,
7.5% oftotal. Not an insignificant amount.

Last time I looked at electicity generation output, gas, nuclear and coal
were all about 33%, now coal is not far off 50%, nuclear about 16% and gas
most of the remainder.

What has caused the drop in nuclear? It can't be all down to the
decommisioning of magnox, surely?

--
B Thumbs
Change lycos to yahoo to reply

Andy Champ wrote:

unlike the output of windmills which is much less
predicable and close to random in distribution through 24 hours.

Damn. Can't find out who wrote that...

... but. You'll find there is a diurnal pattern in the wind. It often
goes light around sunset, especially in areas where there's a sea breeze
powered by temperature difference between the land and the water.

only at ground level

Up a 100ft its blowing just the same.

Andy.

wrote:
On 25 Nov,
Roger Chapman (and others) wrote:

And I see that you at least think that maximum wind power at the time
of minimum demand is not a problem.
at the moment its relatively pathetic so it isn't.
You sure about that?

It seems to have been around 50% of nuclear output for the last day or two,
7.5% oftotal. Not an insignificant amount.

Last time I looked at electicity generation output, gas, nuclear and coal
were all about 33%, now coal is not far off 50%, nuclear about 16% and gas
most of the remainder.

What has caused the drop in nuclear? It can't be all down to the
decommisioning of magnox, surely?

Torness was off line.
Grid fault.

Takes a few days to come back on.

That's about 1GW

Couple of other reactors are running low due to end of life constraints
- no point in fixing em as they are due to close soon.

Al.so the sea is warm. That drops the power output from the final stage
condensers

On 25/11/2011 22:38, Andy Champ wrote:

unlike the output of windmills which is much less
predicable and close to random in distribution through 24 hours.

Damn. Can't find out who wrote that...

... but. You'll find there is a diurnal pattern in the wind. It often
goes light around sunset, especially in areas where there's a sea breeze
powered by temperature difference between the land and the water.

Twas me.

It is my understanding that sea breezes are essentially a local
phenomenon and would not effect either off shore or inland wind farms.
It is quite possible that there is a statistically significant pattern
to wind but looking at the wind speed record from my weather station
over the last few weeks it is not immediately obvious.


--
Roger Chapman

On 25/11/2011 21:58, Dave Liquorice wrote:

Irrelevant for domestic PV installations. 4KW is well below the load
that even the meanest domestic connection will supply so no additional
infrastructure is required.

At the current low density of domestic PV systems but how many would
you need in a given area before the substation connected to them
became "undersized"?

Base load of an occupied house is around 1kW but these PV system have
peak output during the day when, generally speaking, homes are empty.
So most of that 4kW will be exported from each installation. Now if
the substation is sized on 1kW/home average once you get over 25% of
homes with PV systems there is potential for the substation to become
overloaded.

As TNP has yet to point out substations will be sized for the 'worst
case scenerio (not to mention future expansion) which could be the
5.30pm peak on the worst day of the year.

A significant number of houses will be occupied all day most days of the
week (pensioners, young families, shirkers, etc.) and even those that
are not have some maybe intermittent load such as freezers.

Not to mention what happens to the voltage in the area when all these
things are trying to export and that export disappears in seconds as
a clouds shadow moves across the neighbourhood.

You may have a point there but shadows move at the same speed as clouds
and the edge is rarely (never?) so significantly pronounced as to be an
on/off switch. The panels will continue to operate at a reduced level
even when not in direct sunlight.

Harry mentioned a figure of 90,000 recently. If the number rises to say
110,000 before the rate of increase reduces to insignificant that is
still only 0.5% of households. I think from now on we are only going to
see PV panels on new builds where they can be built in from scratch
with, in time, significant savings in roof construction to offset the
cost of the panels. How much does half a roof of tiles (or slates) cost.
The only price I know off hand (because I happened to be costing my roof
recently) is £420+ a ton for second hand Yorkshire stone slates (in the
order of 15 - 20 tons per roof). Concrete tiles would be much cheaper
and should weigh much less.

--
Roger Chapman

Roger Chapman wrote:
On 25/11/2011 21:58, Dave Liquorice wrote:

Irrelevant for domestic PV installations. 4KW is well below the load
that even the meanest domestic connection will supply so no additional
infrastructure is required.

At the current low density of domestic PV systems but how many would
you need in a given area before the substation connected to them
became "undersized"?

Base load of an occupied house is around 1kW but these PV system have
peak output during the day when, generally speaking, homes are empty.
So most of that 4kW will be exported from each installation. Now if
the substation is sized on 1kW/home average once you get over 25% of
homes with PV systems there is potential for the substation to become
overloaded.

As TNP has yet to point out substations will be sized for the 'worst
case scenerio (not to mention future expansion) which could be the
5.30pm peak on the worst day of the year.

A significant number of houses will be occupied all day most days of the
week (pensioners, young families, shirkers, etc.) and even those that
are not have some maybe intermittent load such as freezers.

Not to mention what happens to the voltage in the area when all these
things are trying to export and that export disappears in seconds as
a clouds shadow moves across the neighbourhood.

You may have a point there but shadows move at the same speed as clouds
and the edge is rarely (never?) so significantly pronounced as to be an
on/off switch. The panels will continue to operate at a reduced level
even when not in direct sunlight.

Harry mentioned a figure of 90,000 recently. If the number rises to say
110,000 before the rate of increase reduces to insignificant that is
still only 0.5% of households. I think from now on we are only going to
see PV panels on new builds where they can be built in from scratch
with, in time, significant savings in roof construction to offset the
cost of the panels. How much does half a roof of tiles (or slates) cost.
The only price I know off hand (because I happened to be costing my roof
recently) is £420+ a ton for second hand Yorkshire stone slates (in the
order of 15 - 20 tons per roof). Concrete tiles would be much cheaper
and should weigh much less.

I think from now on solar PV will die a death and be as common as
Formica on new builds.

Quite simply no one is going to pay extra to have it, as it represents
an overhead maintenance wise, and a dubious benefit.