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Coming shortage of UK generating capacity?
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adam2
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PostPosted: Mon Sep 19, 2016 3:57 pm    Post subject: Coming shortage of UK generating capacity? Reply with quote

For some years the margin of UK generating capacity over demand has been falling, so far without any serious consequences.

Demand has been falling for some years, but available capacity has been falling faster, mainly due to the closure of coal burning power plants.

In at least the last two winters, power cuts have been averted only by luck rather than by availability of a prudent margin of generating capacity.

Some of the more alarmist press reports refer to "running out of power" and seem to imply a reserve or stockpile of electricity that will soon be consumed and result in the lights going out permanently.

Something a lot more dramatic than a shortage of generating capacity would be required to cause a long term blackout.

Much more likely is a shortage of up to a few GW at peak times, resulting in perhaps 5% or at worst about 10% of the country being blacked out for an hour or two on a few or at worst a few dozen winter evenings a year.

It is important to appreciate that any sudden shortage of capacity results in the speedy and fully automatic disconnection of large areas.
There can be no QUESTION WHATSOEVER OF ANY WARNING, CONSULTATION OR EXCEPTIONS under such circumstances. This has happened, though only once in recent years IIRC.

If a bit more warning of potential shortages is available, then a power cut rota can be published and those customers who know in what load group they fall will have some warning as to when they are likely to be cut off.
This happened regularly decades ago, but not recently.
During pre-planned rota cuts EVERY small and medium size customer in the affected area will be cut off. NO EXCEPTIONS can be made for the ill, vulnerable, young children, or vital services such as hospitals, police stations, old peoples homes, pharmacies, transport facilities and the like.

A very small number of large consumers that have their own dedicated high voltage grid connection, AND are judged to be off great importance can be exempted from rota cuts. This applies to only a small number of customers and has to be agreed in advance.
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adam2
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PostPosted: Wed Sep 21, 2016 5:43 pm    Post subject: Reply with quote

Here is my reasonably PESSIMISTIC estimate of available UK generating capacity for the coming winter.
In this I have made moderately pessimistic estimates of peak availability, based so far as possible on previous experience.

CCGT--------24GW a modest increase on last winter to allow for new build.
Nuclear-------6GW it was routinely that low in a recent winter.
Coal----------8GW, a significant reduction due to the many closures.
Hydro--------1 GW, limited but reliable.
Pumped -----2GW cant be sustained but useful for the peak.
Biomass------2 GW was consistant last winter, no change expected.
OCGT/Diesel-1GW increase since last year as more has been built.
Wind----------1GW is often a lot more, but about 1GW can be counted on.
Interconnectors- 1.5GW is about all that be counted on.

Or about 46.5GW in total.
In exceptionally severe weather, peak demand might reach 56 GW though it has not been that high for some years. That would imply a substantial level of disconnections during the winter evening peak, IF demand reached an exceptional 56GW.
At a more likely winter evening peak of 53GW, disconnections could still be significant.

This is however a moderately pessimistic view.
I will repeat the exercise making reasonably optimistic assumptions.
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adam2
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PostPosted: Wed Sep 21, 2016 5:58 pm    Post subject: Reply with quote

Here is a moderately OPTIMISTIC view of available generating capacity for the coming winter evening peak.

CCGT--------26 GW, assuming significant new capacity since last winter
Nuclear-----7.5GW it has fairly regularly been that much.
Coal---------8.5GW, That AFAIK, is about all we have left.
Hydro--------1GW, not expected to alter much.
Pumped------2GW
Biomass------2GW was consistent at that figure last winter
OCGT/Diesel--1.5GW, assumes a fair bit of new capacity.
Wind ---------2GW, might be more, but counting on 2GW is generous.
Interconnectors-2GW, hopefully.

A total of about 52.5GW, making reasonably optimistic estimates and assumptions.

Also optimistically assuming that peak demand does not exceed 52.5GW, then we should just about muddle through.
A cold winter and a series of breakdowns could be interesting though!
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vtsnowedin



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PostPosted: Wed Sep 21, 2016 6:04 pm    Post subject: Re: Coming shortage of UK generating capacity? Reply with quote

adam2 wrote:
For some years the margin of UK generating capacity over demand has been falling, so far without any serious consequences.

Demand has been falling for some years, but available capacity has been falling faster, mainly due to the closure of coal burning power plants.

In at least the last two winters, power cuts have been averted only by luck rather than by availability of a prudent margin of generating capacity.

Some of the more alarmist press reports refer to "running out of power" and seem to imply a reserve or stockpile of electricity that will soon be consumed and result in the lights going out permanently.

Something a lot more dramatic than a shortage of generating capacity would be required to cause a long term blackout.

Much more likely is a shortage of up to a few GW at peak times, resulting in perhaps 5% or at worst about 10% of the country being blacked out for an hour or two on a few or at worst a few dozen winter evenings a year.

It is important to appreciate that any sudden shortage of capacity results in the speedy and fully automatic disconnection of large areas.
There can be no QUESTION WHATSOEVER OF ANY WARNING, CONSULTATION OR EXCEPTIONS under such circumstances. This has happened, though only once in recent years IIRC.

If a bit more warning of potential shortages is available, then a power cut rota can be published and those customers who know in what load group they fall will have some warning as to when they are likely to be cut off.
This happened regularly decades ago, but not recently.
During pre-planned rota cuts EVERY small and medium size customer in the affected area will be cut off. NO EXCEPTIONS can be made for the ill, vulnerable, young children, or vital services such as hospitals, police stations, old peoples homes, pharmacies, transport facilities and the like.

A very small number of large consumers that have their own dedicated high voltage grid connection, AND are judged to be off great importance can be exempted from rota cuts. This applies to only a small number of customers and has to be agreed in advance.
Do your hospitals and police stations not have backup generators in place? Their installation here in the USA is routine down to much lower level priorities such as water or waste water pumping stations.
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Potemkin Villager



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PostPosted: Wed Sep 21, 2016 6:08 pm    Post subject: Re: Coming shortage of UK generating capacity? Reply with quote

adam2 wrote:


Demand has been falling for some years, but available capacity has been falling faster, mainly due to the closure of coal burning power plants.



It certainly is of note that UK demand has peaked! I wonder though
if that is in terms of annual consumption or winter peak demand as well.

This situation could never ever have been begun to be imagined in the halcyon command economy days when Lord Marshall was firmly at the helm of the CEGB in the 1970s.

Then power station (mainly nuclear) building and grid upgrading programmes were hugely lavish and incredibly expensive affairs predicated on highly (some said insanely) optimistic load growth predictions. Indeed the good Lord Marshall, as the name suggests, did bring to the affair a somewhat military approach that didn't seem all that out of place at the height of the cold war .

At first glance it might be simply concluded that reducing demand means that less power stations are needed just as it might be simply concluded that installing more wind and solar PV generation will have the same effect.
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adam2
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PostPosted: Wed Sep 21, 2016 7:03 pm    Post subject: Re: Coming shortage of UK generating capacity? Reply with quote

vtsnowedin wrote:
.]Do your hospitals and police stations not have backup generators in place? Their installation here in the USA is routine down to much lower level priorities such as water or waste water pumping stations.


Yes, hospitals and most police stations do have standby generators and some of these might even work when called upon !

It is however widely and erroneously believed that such facilities will be exempted from power cuts.
I once met a senior police officer who stated that he would "not permit the police station to be cut off. Any person sent to cut us off would not be admitted to the station, or as a last resort would be arrested"

Note that the officer seemed to believe that someone would walk around cutting consumers off one at a time, and that cutting off could be avoided by refusing admission or arresting them. I do not think that he believed me when I stated that power cuts are done remotely, a whole district at a time.

This was after I had pointed out that whilst the police station WAS equipped with a generator, that this was of very limited capacity and supplied only very basic lighting. This consisted of a single 40 watt bulb in each office and some 25 watt bulbs on stairs.
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vtsnowedin



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PostPosted: Wed Sep 21, 2016 10:00 pm    Post subject: Re: Coming shortage of UK generating capacity? Reply with quote

adam2 wrote:
vtsnowedin wrote:
.]Do your hospitals and police stations not have backup generators in place? Their installation here in the USA is routine down to much lower level priorities such as water or waste water pumping stations.


Yes, hospitals and most police stations do have standby generators and some of these might even work when called upon !

It is however widely and erroneously believed that such facilities will be exempted from power cuts.
I once met a senior police officer who stated that he would "not permit the police station to be cut off. Any person sent to cut us off would not be admitted to the station, or as a last resort would be arrested"

Note that the officer seemed to believe that someone would walk around cutting consumers off one at a time, and that cutting off could be avoided by refusing admission or arresting them. I do not think that he believed me when I stated that power cuts are done remotely, a whole district at a time.

This was after I had pointed out that whilst the police station WAS equipped with a generator, that this was of very limited capacity and supplied only very basic lighting. This consisted of a single 40 watt bulb in each office and some 25 watt bulbs on stairs.

The standby generators I have dealt with were sized to keep the facility they were installed for fully functioning for days at a time. They kick on automatically within ten seconds of the loss of mains power and shut down as soon as the mains power resumes. Such units have a program that has them turn on once a week for long enough to fully warm the engine and drive off any accumulated condensation to keep things in working order.
They vary in size from a propane powered V8 truck engine for a pumping station to a locomotive sized cat diesel for a hospital.
If you have such in place then it does not matter if the neighborhood gets cut off by a rotacut. Ten seconds later the lights will be on everywhere it matters. However it would suck to be on the operating room table at a critical point in the procedure when the lights blinked and the heart lung machine hiccuped.
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Potemkin Villager



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PostPosted: Thu Sep 22, 2016 10:38 pm    Post subject: Reply with quote

I am delighted to hear the very convincing sounding assertion that mains fail electrical backup systems in the US operate to peerless German standards of reliability and are designed and maintained to to be totally fit for purpose and ready to spring into faultless action, as and when required, to deliver a seamless DEFCON1 user experience.

This does not square with an experience I noted when visiting Los Angeles a number of years ago. California is region where earthquakes are frequently experienced and respecting this an above average number of (very ugly) power utility lines and transformers are mounted on above ground poles, rather than underground via SWA cables, so that damaged segments can be more easily identified and repaired following an earthquake.

Such an overhead line at Los Angeles International airport was brought down by a truck running into a utility pole. This severed the conductors and the entire airport complex, including radar, computer center (sic) and the air traffic control system was shut down.

Thereafter the computer center UPS batteries apparently faded much more rapidly than anticipated and the backup diesel generator(s) failed to start. The entire air traffic control system for the LA area was out of action for 3 hours, despite a plethora of vehicles with flashing blue lights rushing to the scene, until temporary emergency generators were eventually deployed.

I am very glad I was not flying that day.
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vtsnowedin



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PostPosted: Fri Sep 23, 2016 1:06 am    Post subject: Reply with quote

Potemkin Villager wrote:
I am delighted to hear the very convincing sounding assertion that mains fail electrical backup systems in the US operate to peerless German standards of reliability and are designed and maintained to to be totally fit for purpose and ready to spring into faultless action, as and when required, to deliver a seamless DEFCON1 user experience.

This does not square with an experience I noted when visiting Los Angeles a number of years ago. California is region where earthquakes are frequently experienced and respecting this an above average number of (very ugly) power utility lines and transformers are mounted on above ground poles, rather than underground via SWA cables, so that damaged segments can be more easily identified and repaired following an earthquake.

Such an overhead line at Los Angeles International airport was brought down by a truck running into a utility pole. This severed the conductors and the entire airport complex, including radar, computer center (sic) and the air traffic control system was shut down.

Thereafter the computer center UPS batteries apparently faded much more rapidly than anticipated and the backup diesel generator(s) failed to start. The entire air traffic control system for the LA area was out of action for 3 hours, despite a plethora of vehicles with flashing blue lights rushing to the scene, until temporary emergency generators were eventually deployed.

I am very glad I was not flying that day.

There is sadly a huge difference between design goals and standards and the long term results after real time maintenance practices are accounted for. When was the airport constructed? What were the rules at that time? Did any airplane crash due to the power outage? And how much will it cost to bring that airport fully up to date.
Do the terrorist defeat us by crashing the majority of our planes or by simply making the cost of airport security so high nobody can afford to fly?
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fuzzy



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PostPosted: Fri Sep 23, 2016 4:32 am    Post subject: Reply with quote

I have seen backup electrical systems fail in datacentres. We don't live in age of resistive loads..
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Catweazle



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PostPosted: Fri Sep 23, 2016 9:36 am    Post subject: Reply with quote

fuzzy wrote:
I have seen backup electrical systems fail in datacentres. We don't live in age of resistive loads..


Switch mode power supplies can cause large current spikes at specific points on the AC, now imagine 1000 of them, all the same, off the same backup system.
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Potemkin Villager



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PostPosted: Fri Sep 23, 2016 12:16 pm    Post subject: Reply with quote

vtsnowedin wrote:


There is sadly a huge difference between design goals and standards and the long term results after real time maintenance practices are accounted for. When was the airport constructed? What were the rules at that time? Did any airplane crash due to the power outage? And how much will it cost to bring that airport fully up to date.
Do the terrorist defeat us by crashing the majority of our planes or by simply making the cost of airport security so high nobody can afford to fly?


Good Lord this sounds just like a corporate press release! I can really see what Richard Feynman was up against with the Challenger inquiry.

I don't recall any suggestion in the reporting at the time that the LAX incident was anything other than a genuine accident. Is struck me as unwise and penny pinching to have such a critical piece of real time transport infrastructure dependent on only one point of connection to the grid.

I am intrigued by the low information content euphemism "real time maintenance practices" and wonder what it can really mean.
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vtsnowedin



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PostPosted: Fri Sep 23, 2016 3:46 pm    Post subject: Reply with quote

Potemkin Villager wrote:


Good Lord this sounds just like a corporate press release! I can really see what Richard Feynman was up against with the Challenger inquiry.

I don't recall any suggestion in the reporting at the time that the LAX incident was anything other than a genuine accident. Is struck me as unwise and penny pinching to have such a critical piece of real time transport infrastructure dependent on only one point of connection to the grid.

I am intrigued by the low information content euphemism "real time maintenance practices" and wonder what it can really mean.

Sorry about that. I've worked for government bureaucracies for forty years so speak and write their language. "Real time" means what the actual schedule ends up being as opposed to what was promised in the original proposal.
In proposals everyone shows up on time and does their job properly per specification.
In real time, managers cut budgets, workers do poor work or skip maintenance because it's not "their job" even when it clearly is, and funds get diverted to other more pressing problems.
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BritDownUnder



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PostPosted: Sat Sep 24, 2016 7:59 am    Post subject: Re: Coming shortage of UK generating capacity? Reply with quote

Potemkin Villager wrote:


This situation could never ever have been begun to be imagined in the halcyon command economy days when Lord Marshall was firmly at the helm of the CEGB in the 1970s.

Then power station (mainly nuclear) building and grid upgrading programmes were hugely lavish and incredibly expensive affairs predicated on highly (some said insanely) optimistic load growth predictions. Indeed the good Lord Marshall, as the name suggests, did bring to the affair a somewhat military approach that didn't seem all that out of place at the height of the cold war .


I remember seeing him on TV, must have been during the 1980s. Looking back now he was obviously a very forward thinking man - though he was not a fan of alternative energy I believe - but at the time he seemed to have a funny, even German sounding accent that i could never understand why that was.
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adam2
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PostPosted: Sat Sep 24, 2016 11:16 am    Post subject: Reply with quote

The grid upgrades done in the 1970s were by no means excessive and have proved their worth in the decades since.
Demand continued to rise for many years and the upgrades only just about kept pace with rapidly growing demand.

Demand has fallen in the last few years but this is a very recent phenomena.

Demand is still rising in London and the south east, despite falling nationally, and some major upgrades are underway, with others planned.
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