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Author Topic: Eastern UK Power cuts  (Read 4506 times)
oliver90owner
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« Reply #45 on: August 21, 2019, 03:10:26 PM »

Roger,

I’m no expert and have to read the news (and between the lines, too!), but as I see it the grid must maintain its frequency close to 50Hz.  If it drops excessively, all those spinning  generators must conform - or else havoc will ensue.  Imagine some generators at one frequency and others at a different frequency mixing output on the grid!

Now all the generators are designed for peak efficiency at, or very near to, 50Hz.  If they all start to ‘droop’, down goes their output and the system spirals into darkness in a very short time - because individual turbines would be tripping out due to a perceived overload or something.  

The grid response is there to avoid that happening.  Usually they do a great job and we don’t notice the hiccups they have to plan for and contend with.  On this occasion the grid responded and maintained/recovered the frequency - but had to drop load to manage that.  The rest is history - lots of people complaining about a grid loss when they should have been complaining about the railway chaos.  We all get power cuts from time to time and we cope.  The railways don’t seem able to get restarted after stalling the engine!  

We have all queued behind the learner driver that stalls the engine at some time?  I know I have!  Now imagine every learner driver stalling at the same time in London rush hour traffic and being unable to restart for hours on end!
« Last Edit: August 21, 2019, 03:12:24 PM by oliver90owner » Logged
dan_b
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« Reply #46 on: August 21, 2019, 03:58:21 PM »

I read somewhere that the train issue was actually a result of firstly the demand side response service actually took the track signalling offline, which meant all the trains had to stop on track. And from there the other issues cascaded.
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Nickel2
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« Reply #47 on: August 21, 2019, 04:09:12 PM »

Philip R, My dad told me many years ago that the distribution run some sort of auto-transformer system that drops the voltage at critical load events, hence the current. This as I understood acted as a 'soft' load shedding. We used to see the lights dip when I was a kid and that was the explanation: Lower current = less load, generator frequency increases to stay within range. At night they'd raise the frequency to average it out for the 24 hour period, so that clocks, timers, etc stayed right.
Is it codswallop?  Huh I'd love to know   genuflect
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Westie
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« Reply #48 on: August 24, 2019, 12:35:47 PM »

Philip R, My dad told me many years ago that the distribution run some sort of auto-transformer system that drops the voltage at critical load events, hence the current. This as I understood acted as a 'soft' load shedding. We used to see the lights dip when I was a kid and that was the explanation: Lower current = less load, generator frequency increases to stay within range. At night they'd raise the frequency to average it out for the 24 hour period, so that clocks, timers, etc stayed right.
Is it codswallop?  Huh I'd love to know   genuflect

I think the tap changers are mostly used by DNOs, on their LV distribution networks, to maintain voltage within the statutory limits.  I don't think NG have any centralised access to those systems.

Actually , another question for Philip, where does the NG control end and DNO start, is it at a certain line voltage, IIRC NG control ends below 33kV?
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splyn
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« Reply #49 on: September 01, 2019, 10:22:34 PM »

Dieter Helm's response to the power cuts:

http://www.dieterhelm.co.uk/energy/energy/power-cuts-and-how-to-avoid-them/

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There are three lessons from this power cut. First, what happened in that hour reveals a central truth about our economy, and that is that security of supply is much more valuable now than even a couple of years ago. The economy is digitalising, and almost everything digital is electric. All our main infrastructures now depend upon a reliable supply of electricity. They all depend upon the communications networks, and they need electricity. When the trains ground to a halt, the transport dependency was stark. When the lights went out, so did all the digital devices in houses and commercial buildings. Even the traffic lights failed. We need a higher level of security of supply than ever before, and as we complete the transition to a digital economy (and net zero) we will need ever more security. What was good enough a couple of years ago is not now. What we need in the next decade is a lot more security.

Second, the power cut revealed just how fragile the system is becoming as it relies on more and more intermittent renewables generation. This may not have caused the power cuts, even if a wind farm drops off, the intermittency of the capacity on the system makes it harder to secure supplies. It is just a fact that a power system with lots of intermittent renewables is harder to manage, and need a lot more extra capacity to absorb and manage both anticipated and unanticipated events. Most renewables power is not firm power. More renewables mandated, by the net zero legal requirement, mean more equivalent firm power.

Third, the power cuts also revealed the exposure of the networks themselves and their resilience. It took out not just one part of the networks but several. This matters, as Ofgem is currently determining how much investment, and therefore resilience, the networks will be allowed to build in after the periodic reviews. More resilience means more investment and capital maintenance cost, something Ofgem will have to consider (along with how far the network companies have been doing sufficiently in the past).

His first point, that security of supply is becoming more important as we become ever more reliant on electrical systems is interesting and not one you seen mentioned very often. It's getting ever more difficult to function without apps - paying for parking, or (indeed almost anything in a cashless society), accessing almost any government service, NHS bookings etc.** Witness the chaos at the tills when the VISA/Mastercard systems went down (last year?) preventing people from purchasing anything and having to abandon trolleys full of shopping in the supermarkets. But we seem to be resigned to the fact that our electricity supply is inevitably going to become less reliable. Why do the government and regulators seem to be so complacent or willing to ignore the issue? It can't be Brexit diverting their attention as it has been going on for years before the vote.

As to his comments on the fragility increasing with increasing renewables penetration, that may be true generally but it wasn't the (direct) cause of this incident - it was down to having inadequate reserve margins. There have been several (many) cases of multiple indepenant failures of large generators, including nuclear generators over the decades which have been been managed. I guess it is due to ever increasing sqeezing of profit margins and inadequate investments in infrastructure which are now starting to become evident as the grid shows its age. I can't say I'm optimistic 'that the power cuts will be a wakeup call to BEIS and the government'; I believe that it will take bigger and longer power cuts to get MPs even talking about the issue let alone doing anything.

**My lads think I'm a dinosaur for not using contactless payments but trying to persuade them to always carry some cash, in case the electronic systems stop working, seems to fall on deaf ears. Perhaps a long walk home because they can't buy a bus or train ticket might wake them up to the possibility...
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JohnS
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« Reply #50 on: September 01, 2019, 11:05:32 PM »

I agree with most of Dieter Helm's comments and Splyn's analysis of them.

What we need for the Grid now is a similar battery bank to the one that Elon Musk built in South Australia.  It would provide 'spinning' reserve and peak capping.  I gather that South Australia's has exceeded its expected savings. Perhaps split it into two or three in different parts of the country.

We also need a critical examination of Ofgem's role.  How much have they squeezed profit margins and the 'regulated asset base' of the grid and generators?  It is all very well for civil servants to demand a report and threaten a fine but they need to see if they were at fault.  I once thought that successive government's energy policy of allowing assets to be sold to foreigners and then screwing them on allowable returns was a 'brilliant' idea, but now the short comings are coming back to haunt us.

We also need to examine our own motives.  As eco minded consumers, we benefit from low standing charges and higher unit costs as we buy less energy.  We need to carefully consider if this attitude hinders resilience and pushes costs onto the poorer section of society who can least afford it.  I fundamentally disagree with those who advocate the 'petrol pump' model of no standing charge and everything in the unit price.

15 years ago I was living and working in South Korea.  There the domestic energy price per unit increased with the numbers of units consumed, so the big home owners paid lots lots more than and subsidised the small flat dwellers.
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azps
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« Reply #51 on: September 02, 2019, 07:33:24 AM »

As usual, some thoughtful bits from Dieter, as well as some bits that omit a crucial element or two:

Quote
There are three lessons from this power cut. First, what happened in that hour reveals a central truth about our economy, and that is that security of supply is much more valuable now than even a couple of years ago.

There are indeed new areas where security of electricity supply is more valuable now. However, there are also some areas where it is less valuable. Fridges and freezers are much better insulated now, and there's much lower risk of consequential loss of food from power cuts. We've got sufficient information and communications technology now to do much smarter load disconnection. Until now, there just hasn't been the political or economic incentive to do actually implement it comprehensively and strategically, rather that just piecemeal.

Here we come up against a real crunch - the English predisposition to just muddle through, versus the overwhelming necessity of strategic long-term planning for complete decarbonisation.

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When the trains ground to a halt, the transport dependency was stark.

Well, sort of, but ... when the trains stopped, something went very wrong that had knock-on consequences into the next day, but that wasn't the fault of a transient drop of generation on the grd. The power shouldn't have been cut to trains & signalling, and didn't need to be. It'll be interesting to see why that happened (I do wonder whether someone had decided to cut corners and save a few pennies by going for an contract with interruptible supply, when they really shouldn't have). Furthermore, the trains should have been up and running again in minutes, but the rebooting of the trains by the drivers failed

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Second, the power cut revealed just how fragile the system is becoming as it relies on more and more intermittent renewables generation.

And that's just straight-up untrue. As Splyn notes, that's not what this power cut was about at all. Power cuts were much more common when we relied only on coal and oil for our electricity.

Quote
Most renewables power is not firm power. More renewables mandated, by the net zero legal requirement, mean more equivalent firm power.

And here's a big red flag: "firm power". That phrase is such a dead giveaway that DH is stuck in yesteryear's mindset. This holding of "firm power" as being the holy grail is tied to a grid that was built on baseload, mid-merit, and peaking plant - but even back in those bad old days, baseload plant was the cheapest. Firm power is a problem, as security of supply depends on flexibility. Flexible power is valuable. Agents on the system that can rapidly contribute up-regulation (increasing supply or decreasing demand) are valuable, as are ones that can rapidly contribute down-regulation. But agents that provide inflexible supply are less valuable. Firm power is a red herring.

His first point, that security of supply is becoming more important as we become ever more reliant on electrical systems is interesting and not one you seen mentioned very often.

We have those discussions at work (energy academia), but I don't know where we'd publish it that it would be of any interest to the general public. Where should we be publishing that sort of discourse? I guess it's a bit too late now, anyway ...

Quote
Why do the government and regulators seem to be so complacent or willing to ignore the issue?

Because the government and Ofgem have a process for valuing loss-of-load. That value (VOLL) is then passed on and used by the regulator and industry agents. But the valuation process isn't able to properly consider the full breadth and complexity of the system. It's quite a traditional method that assumes that all the costs are captured if we just ask homes how much they're willing to pay to avoid lost load (or willing to accept in compensation in case of loss of load), and find out how much production would be lost if companies suffer loss of load.
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brackwell
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« Reply #52 on: September 02, 2019, 07:42:41 AM »

Zero problems require infinite resources and investment something i am sure the public do not wish to pay for.  The modern way of working does not allow for failures and errors but they will always exist and accept there are risks with everything we do.  Everytime we go on the roads we accept we could be one of the 30/day killed there and everyday we rely on leccy we have to remember it will not always be there.  Now where are those candles, cash,wind up clocks,batts,blankets ......

The train probs were their own b faults!

Waiting to see the full report.

Ken
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brackwell
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« Reply #53 on: September 02, 2019, 08:16:10 AM »

Long term planning is always touted as the way forward by all those "back seat drivers" but if they had their hands on the steering wheel they would be just as bad.  Why -because we live in a fast changing and oft unpredictable ways.  On ones long term plan would we have taken in to account the plummiting cost of solar, wind and batts and the almost abrupt change to EVs and net zero and then the unknown unknowns just round the corner. Flexible thinking and actions is what is required and that is what makes Britain great.

Ken
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oliver90owner
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« Reply #54 on: September 02, 2019, 09:29:34 AM »

Everytime we go on the roads we accept we could be one of the 30/day killed there ....

C’mon Ken,  I very much doubt that most of the population even think about it, let alone accept it. Smiley Smiley. Certainly most of the younger generation think “it will never happen to me”.

Only when something goes wrong do they wake up to the ‘facts’.  And even then they accept the hyped-up jingoistic journalist reports in the daily fail (or similar publications) or the audible complaints from the ‘unknowing’ on the radio or the litany of conspiracy theories abounding on the internet!
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stannn
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« Reply #55 on: October 04, 2019, 09:47:07 PM »

https://www.rechargenews.com/wind/1859637/questions-remain-over-uk-blackout-part-caused-by-offshore-wind-giant
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Philip R
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« Reply #56 on: October 04, 2019, 11:34:46 PM »

Funny old thing, I recorded a programme, which I have somewhere, a 1988/89 Panorama prior to the privatisation of the CEGB. On it was a younger Dieter Helm, extolling the virtues of a breakup of the state owned CEGB and the high cost of nuclear when built with treasury bond money. How a leopard changes his spots!

Philip R
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