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Agile plunge pricing predictions
- Thread starter philgods
- Start date
Glan gluaisne
Active Member
There was never any issue over there being a potential generation shortfall causing power outages at all, if the media were reporting that then it's just fake news, and shows that they just don't understand the contractual basis of the UK electricity supply business. The margin notice is primarily a contractual instrument that enables procurement of electricity from plants that are normally on standby, nothing to do with forecasting possible power outages. The warming up of the shut down coal plants at West Burton and Ratcliffe was routine following the publication of the notice, coal plants are always on standby to fire up if the forecast is that there may be a shortfall. It is potentially costly, though, as electricity from coal carries a price premium.
The only issue might have been if there had been a problem warming these plants up and bringing them online. If that happens, then the margin notice would have remained in place, to allow other plant to come on line. If other plant also suffered warm up problems, and couldn't come online in time, then in the worst case the fields of diesel gensets that are there for last-ditch backup might be fired up. There are loads of options open to NG, including asking DNOs to start priority load shedding, if push comes to shove.
The only issue might have been if there had been a problem warming these plants up and bringing them online. If that happens, then the margin notice would have remained in place, to allow other plant to come on line. If other plant also suffered warm up problems, and couldn't come online in time, then in the worst case the fields of diesel gensets that are there for last-ditch backup might be fired up. There are loads of options open to NG, including asking DNOs to start priority load shedding, if push comes to shove.
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This alarmist trash from the Times
Blackouts fear forces power alarm at National Grid | Business | The Times
Blackouts fear forces power alarm at National Grid
National Grid last night sent out an urgent call for more power stations to fire up to keep Britain’s lights on today...
Blackouts fear forces power alarm at National Grid | Business | The Times
Blackouts fear forces power alarm at National Grid
National Grid last night sent out an urgent call for more power stations to fire up to keep Britain’s lights on today...
Glan gluaisne
Active Member
Alarmist trash sums that up well. Bloody journalists should spend ten minutes reading up on the contractual framework that the NG works to, and reading up on how the NG has pretty robust processes in place to manage the complex balance between supply and demand, in order to keep the grid stable. The generators are all on differing contracts to supply electricity to the grid, with some generators being paid to sit on standby, with set warm up times before they come online. Pretty much all of the coal plant is like this, and stays shutdown for much of the time, barring maintenance runs needed to keep the plant serviceable. It takes a long time to fire a coal generating plant up from cold, though, several hours, so there needs to be a system in place to trigger this, with the higher cost implications that come with it.
If things really do get serious, such as almost happened in the Hornsea/Little Barford incident last year, then NG can, and do, automatically instruct DNOs to selectively load shed, based on the level of frequency dip. This is another contractual process, where all consumers on the lowest priority tariffs are shut down, with the DNOs stepping up the priority tariff list until such time as the grid frequency stabilises. These shut downs are to commercial/industrial consumers, who have agreed to a cheaper tariff in return for accepting that they will lose power first. The priority level of pretty much all commercial/industrial customers is lower than that of things like hospitals, and it's only domestic consumers with smart meters that can be easily shut off, as shutting down LV grid sections normally requires someone to physically go out and disconnect parts of the network, as most of it doesn't have remote switching (one of the primary reasons behind smart metering was originally to provide a quick, remote, shut down, and restart, capability).
If things really do get serious, such as almost happened in the Hornsea/Little Barford incident last year, then NG can, and do, automatically instruct DNOs to selectively load shed, based on the level of frequency dip. This is another contractual process, where all consumers on the lowest priority tariffs are shut down, with the DNOs stepping up the priority tariff list until such time as the grid frequency stabilises. These shut downs are to commercial/industrial consumers, who have agreed to a cheaper tariff in return for accepting that they will lose power first. The priority level of pretty much all commercial/industrial customers is lower than that of things like hospitals, and it's only domestic consumers with smart meters that can be easily shut off, as shutting down LV grid sections normally requires someone to physically go out and disconnect parts of the network, as most of it doesn't have remote switching (one of the primary reasons behind smart metering was originally to provide a quick, remote, shut down, and restart, capability).
Glan gluaisne
Active Member
If anyone wants reassurance, I've just had a quick look at the NG status, and far from there being a shortfall, we are currently exporting just under 1 GW via two of the HVDC interconnects. Ireland is buying "spare" electricity from us at the moment, and we're buying electricity in from France and the Netherlands. The coal plants are starting to come on line, just under 1 GW as of a short time ago, so that's more than the forecast 740 MW shortfall that the NG were asking generators to supply (in reality, bid for, as it's a price-driven market).
I'm going to take advantage of some free ChargePlace Scotland charging tonight whilst it's still free.
When I bought this car I really didn't expect to be monitoring market rates so closely, what with the Tesla share price and the Agile energy price there's a lot of highs and lows not normal with traditional car ownership!
Glan gluaisne
Active Member
Coal is now up around 1.7 GW, so it looks like the coal plants are now pretty much fully online. Octopus will probably be losing money, even at a retail price sitting at the 35/kWh cap, as I suspect that the wholesale spot market price might come close to exceeding the retail price cap for an hour or two today and tomorrow. Right now, renewable generation (which is pretty much our cheapest generator) is way down at just under 7 GW. That's a fraction of what it was a week ago, and is why the price is increasing.
Drew57
Active ember
We've got 35p at 17:00-19:00 tomorrow but even then, a four hour night time slot only averages 7.45p if I needed it (I don't)
Also to get things in perspective, a year ago I was on a tariff around 16p, higher standing charge and £550pa for diesel + car tax.
Also to get things in perspective, a year ago I was on a tariff around 16p, higher standing charge and £550pa for diesel + car tax.
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There is a 12p per kWh penalty on top of their normal margin (2.1) that Octopus insert during the period 16:00 - 19:00 daily so on average Octopus will be doing very nicely. The cap will just eat in to that 12p.
Actually looking at the current UK power generation, maybe the alarmist trash was correct.
The available nukes are at max chat producing just 6.25 GW (1.5GW down from this time last year)
The gas turbines are producing 23GW, the highest figure since Jan 19.
The NG have had to call on the last remaining coal stations to light up - they are producing 2.1GW
Additionally we are sucking hard on the European interconnectors.
Let's hope the wind doesn't drop because it's still supplying 2.9GW
I actually think we are very poorly placed in the event of an "event"
It doesn't bode well for winter.....
The available nukes are at max chat producing just 6.25 GW (1.5GW down from this time last year)
The gas turbines are producing 23GW, the highest figure since Jan 19.
The NG have had to call on the last remaining coal stations to light up - they are producing 2.1GW
Additionally we are sucking hard on the European interconnectors.
Let's hope the wind doesn't drop because it's still supplying 2.9GW
I actually think we are very poorly placed in the event of an "event"
It doesn't bode well for winter.....
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Glan gluaisne
Active Member
It's all about timing. We're using the HVDC interconnects because the price is low from France, Belgium and the Netherlands at the moment - the UK is currently around £70/MWh, France and the Netherlands are around at €45/MWh, so the market is operating normally, and buying from Europe as the price is lower than paying to fire up more coal plants, or, heaven forbid, firing up all the hundreds of standby diesel gensets, that allow some essential services (mainly water) to be disconnected from the grid as a part of structured load shedding.
Peak demand management, if push comes to shove, will be by disconnecting low priority commercial/industrial consumers, if things get really tough, and there is no available generation capacity. Doesn't happen often, but it is a fast-reacting way to deal with a lack of generation or distribution capacity. Some of the reported outages from the Hornsea/Little Barford incident were not failings in the grid, they were agreed disconnections as a part of structured load shedding. At least one consumer, Newcastle Airport, hadn't read the small print when they signed up to a cheaper tariff. They failed to realise the implications of being a first tier disconnect customer - in their case it took them several hours to reboot all their normal operating, safety and security systems when power came back on after they were turned off for a few minutes.
We're still exporting just under 1.4 GW to Ireland at the moment, too. If push came to shove, and it made economic sense to switch those HVDC interconnects off, then that would give us a fair bit more capacity. The estimated requirement for additional peak generation that was advertised in the margin notice first thing this morning was only 740 MW, so not a great deal in the overall scheme of things.
Glan gluaisne
Active Member
Gridwatch gives pretty good information on demand and the breakdown of generation. Spot market pricing is available from a couple of sites, but the actual wholesale prices paid are not made public, so all that's available is base and peak pricing, plus an indicative 30 minute price. Most of the NG procedures and contractual arrangements they have with generators are on their website, so a few hours reading can get you up to speed with how the market operates. A read of some of the reports on grid events provides a useful insight into the challenges involved. I believe that the 1987 storm event report may be available on the web, I have an old photocopy of it. It's interesting, because the UK had two entirely separate grids for about two weeks after the storm - the north and south operated asynchronously after several disconnects severed the country in half, to protect as much of the system as possible from an excessive frequency dip. The NG had to spend days getting the north and south grids phase synchronised, so that there was near-zero phase error when they reconnected the two halves up again. The recent Hornsea/Little Barford incident report is well worth a read (it's online) as it illustrates how the grid has to react in order to arrest a significant frequency dip. As it was, the dip was enough to cause an extensive cascade failure, as lots of distributed generators went offline for self-protection as the frequency dropped below about 49 Hz.
ACarneiro
Active Member
All that drama for a 1Hz frequency change.
The tolerances we work with these days are truly astounding
The tolerances we work with these days are truly astounding
Glan gluaisne
Active Member
All that drama for a 1Hz frequency change.
The tolerances we work with these days are truly astounding
The problem with AC power transmission is that it is incredibly frequency sensitive. A very small dip in frequency signals that demand exceeds supply, and conversely a very small frequency increase signals that supply exceeds demand. NG works to a normal allowable frequency error of 50 Hz, +/- 0.2 Hz. In practice the frequency never usually gets close to those operational limits, it's usually constrained to be within about 0.1 Hz of 50 Hz. There is a statutory obligation on the grid to not allow the frequency to ever be outside a 50 Hz +/- 0.5 Hz band. The NG publish a guide on the mandatory frequency response for generators here: https://www.nationalgrid.com/sites/default/files/documents/Mandatory Frequency Response Guide v1.1.pdf
At 49.5 Hz, a lot of things will start to automatically disconnect themselves from the grid, for self-preservation. This means that things like grid tied inverters, that form part of all the distributed generation around the UK (small scale solar and wind) will all automatically disconnect to prevent damage. One consequence of that is that it makes the grid less stable, as it can result in a cascade failure.
There's a good description of the way that the grid can come close to failing because of a frequency dip and resultant cascade failure in the Hornsea/Little Barford incident report. Worth a read, as it gives a good insight into how some parts of the grid are managed:
https://www.ofgem.gov.uk/system/files/docs/2019/09/eso_technical_report_-_final.pdf
https://www.ofgem.gov.uk/system/files/docs/2019/09/eso_technical_report_-_appendices_-_final.pdf
Both Hornsea and Little Barford received massive fines for breaching their statutory requirements, £4.5 million each, made as "voluntary" payments, as both admitted liability. The frequency dipped down to 48.8 Hz during that event, so every grid-connected small scale generator, such as all the tens of thousands of solar panel installations across the UK, dropped off line to protect themselves. These wouldn't re-connect until the frequency went back above 49.5 Hz for some time, and to get the frequency back up the grid needed DNOs to very quickly load shed. It was the load shedding of commercial consumers, like electric rail services and Newcastle Airport, that caused much of the disruption. Failures within both Newcastle Airport's own systems, and within some electric rolling stock, led to the chaos that ensued. In the case of some trains, the only way to get them to turn back on was for an engineer to connect a laptop to them to manually reboot them, believe it or not.
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MrBadger
Badger out
Fascinating how EV ownership stimulates our interest in such matters. Before getting one, I would have struggled to tell you what unit of measurement was on my leccy bill, let alone what the price for it was. I don’t think I was unusual in that regard either judging by the growing popularity of comparison and auto switch websites for consumers.
Who knew that there was a budding eco-warrior lurking inside me.
Who knew that there was a budding eco-warrior lurking inside me.
Glan gluaisne
Active Member
Is that the data from your PV system during this event?
Seems to illustrate the low frequency disconnect well, with the generated power dropping to zero. It looks as if the data has been smoothed, though, as in reality the frequency dip when the initial problem arose, the shut down of Hornsea and the first generator going offline at Little Barford, was pretty fast. The frequency dropped from close to 50 Hz, down to below the 49.5 Hz disconnect threshold in about 7 or 8 seconds. The frequency recovered back to above 49.5 Hz just over 3 minutes after the start of the event, and was fully recovered back to about 50 Hz by about 4 minutes 45 seconds. The frequency then overshot, as a consequence of load shedding now causing the restored supply capacity to exceed demand - demand had been cut by the DNOs operating LFDD (low frequency demand disconnection) to all their first tier consumers, whilst extra standby generation had come online, plus all the distributed small scale generation automatically started to reconnect.
