Wind Power and UK Energy Use

[edwin_m]

Solar plus wind is still near 80%. As the grid is working now, when will this issue arise?

This risk is when a generator or some part of the grid unexpectedly goes offline. However, as noted by @AndrewE, there are ways of dealing with this without having to maintain fossil fuel generation.

 

[Nottingham59]

So who is paying for the gas installations sitting on spinning standby for the occasions when a cloud covers the sun.

Solar and wind don't vary that quickly - it takes hours for a weather system to cross the country. Gas plants will be started up and stood down as needed to match demand and a variable supply of renewables.

The national grid seems to have a set minimum for gas generation of around 2GW, as you can see on gridwatch here:

Combined Cycle Gas Turbine(CCGT) power production

GB Combined Cycle Gas Turbine(CCGT) Generation

gridwatch.co.uk

I presume this is set by National Grid to guarantee enough inertia and spinning reserve in the system. Over time, I would expect that minimum level of gas generation to dwindle as battery storage, interconnectors and other generators configure themselves to provide the necessary inertia and load response, but I don't know how long that process will take.

 

[Ken H]

Solar plus wind is still near 80%. As the grid is working now, when will this issue arise?

when there is a sudden drop in renewals output. Maybe as a front goes over. Or a renewable power station suddenly goes off stream. In 2019 a gas turbine and a north sea wind farm went off line at about the same time. There was only just enough to keep the grid stable, but tine frequency monitoring units on the SIemens units on thre west cooast lie all tripped and wrecked the timetable. If there is enough rotating generated electricity the frequency drops slowly due to intertia. Too much inverted created AC electric and it drops out of specification in a few seconds.

 

[AndrewE]

when there is a sudden drop in renewals output. Maybe as a front goes over. Or a renewable power station suddenly goes off stream. In 2019 a gas turbine and a north sea wind farm went off line at about the same time.

You still can't recognise synchronous condensers then? See e.g. "ABB’s synchronous condensers go live in Liverpool to stabilize the UK’s power grid" https://new.abb.com/news/detail/101...-in-liverpool-to-stabilize-the-uks-power-grid ... (and there are several more around the country.) And fronts don't "go over" totally unexpectedly!

There was only just enough to keep the grid stable, but tine frequency monitoring units on the SIemens units on thre west cooast lie all tripped and wrecked the timetable. If there is enough rotating generated electricity the frequency drops slowly due to intertia. Too much inverted created AC electric and it drops out of specification in a few seconds.

Is that an informed opinion from a professional in the industry? I was under the impression that the Grid has paid out for suppliers to invest quite a bit in "rotating generated electricity" - aka synchronous condensers.
and by the way, if a

renewable power station suddenly goes off stream.

then it's probably less likely to be the RE's fault than a grid or substation fault - which is equally likely to affect an old-fashioned fossil-fuel (or for that matter nuclear) power station. If you see a massive plume of "steam" from a nuclear power station it means a turbine has gone abruptly offline. I have seen it!

 

[HSTEd]

then it's probably less likely to be the RE's fault than a grid or substation fault - which is equally likely to affect an old-fashioned fossil-fuel (or for that matter nuclear) power station. If you see a massive plume of "steam" from a nuclear power station it means a turbine has gone abruptly offline. I have seen it!

There are other circumstances where steam will be released from a turbine system other than an unexpected trip.
Especially on the earlier AGR stations, the plants may be running with part of their feedwater system isolated, or having just started up.

 

[AndrewE]

There are other circumstances where steam will be released from a turbine system other than an unexpected trip.
Especially on the earlier AGR stations, the plants may be running with part of their feedwater system isolated, or having just started up.

but it was an ex-nuclear power station engineer who said to me something like "Someone will have a very red face or an uncomfortable interview after that!" I think the loss of a significant weight of pure water from the turbine circuit would have come at an appreciable cost.

 

[HSTEd]

but it was an ex-nuclear power station engineer who said to me something like "Someone will have a very red face or an uncomfortable interview after that!" I think the loss of a significant weight of pure water from the turbine circuit would have come at an appreciable cost.

Water lost from the turbine circuit is a measurable cost, for sure, but a 660MW AGR produces something like a million pounds of electricity per day. If dumping steam from the circuit allows the plant to remain operational then its still probably the correct choice.

 

[Bald Rick]

Currently got circa 80% of our energy coming from all renewables, while also not net importing. The week ahead is also looking at similar wind and sun conditions so should see more of this. Would be good to finally start seeing battery storage usage, I haven't found anywhere with live reporting on when this is charging/discharging, but given it's becoming an increasingly large feature of our grid, this will need to be done promptly.

Dogger Bank A has been coming on line for the last few weeks - right now (2140 Sun) it‘s pumping out 437MW, 37% of its plated capacity. The rest of the North Sea windfarms are nearer 80% of capacity (Seagreen is at 93%), so it is safe to say that there’s more to come.

So who is paying for the gas installations sitting on spinning standby for the occasions when a cloud covers the sun. This is called 'flexing' and is very bad for old gas turbines.

They are not on spinning standby, or at least most of them are not.

The national grid seems to have a set minimum for gas generation of around 2GW, as you can see on gridwatch here:

Combined Cycle Gas Turbine(CCGT) power production

GB Combined Cycle Gas Turbine(CCGT) Generation

gridwatch.co.uk

I presume this is set by National Grid to guarantee enough inertia and spinning reserve in the system. Over time, I would expect that minimum level of gas generation to dwindle as battery storage, interconnectors and other generators configure themselves to provide the necessary inertia and load response, but I don't know how long that process will take.

as little as 4 years ago that gas minimum was 5GW. National Grid had a plan a few years ago to run the whole grid for an hour without any fossil fuels* this year; I don’t know whether that is still on but if it is it will be in the next 6 weeks.

*taking a liberal view of the generation mix of imports

In 2019 a gas turbine and a north sea wind farm went off line at about the same time. There was only just enough to keep the grid stable, but tine frequency monitoring units on the SIemens units on thre west cooast lie all tripped and wrecked the timetable.

It was 20 September 2021
The Siemens units were on the MML and ECML.
Other than that, correct.

(there was a seperate grid frequency event in August 2019)

 

[Nicholas Lewis]

Solar and wind don't vary that quickly - it takes hours for a weather system to cross the country. Gas plants will be started up and stood down as needed to match demand and a variable supply of renewables.

They do clouds cover solar panels very quickly and they deload. The wind gusts and wanes and the turbines power output adjust accordingly. Thing is with wide dispersal of solar and wind farms across the UK these variations tend to be noise in the background when the system is well loaded. It does become more of a challenge to mange frequency when the system is lightly loaded with high renewable penetration which is why NESO deploys a number of ancillary services to manage frequency. The fast acting services of Dynamic Response and Dynamic Moderations are largely battery provided as they can can act very fast to frequency deviations. NESO determines how much capacity to procure every four hours to match generation mix.

The national grid seems to have a set minimum for gas generation of around 2GW, as you can see on gridwatch here:

Combined Cycle Gas Turbine(CCGT) power production

GB Combined Cycle Gas Turbine(CCGT) Generation

gridwatch.co.uk

I presume this is set by National Grid to guarantee enough inertia and spinning reserve in the system. Over time, I would expect that minimum level of gas generation to dwindle as battery storage, interconnectors and other generators configure themselves to provide the necessary inertia and load response, but I don't know how long that process will take.

NESO require a minimum of 120GVAs of inertia currently which is considerably reduced from what used to be available from 10yrs ago when the system was dominated by 500MW coal sets. This can be sourced from CCGTs, hydro and the likes of Drax when their generating. They also have five synchronous condensors now installed around the grid. Then there are sources of synthetic inertia like batteries. If the proposed generation mix is insufficient NESO has contracts for interia support and can call on hydro or gas plants to run virtually unloaded but with the spinning mass of the generator.

NESO are revered around the world and our grid is run very conservatively which comes with a cost but thats the price of keeping the lights on.

 

[InTheEastMids]

In 2019 a gas turbine and a north sea wind farm went off line at about the same time. There was only just enough to keep the grid stable, but tine frequency monitoring units on the SIemens units on thre west cooast lie all tripped and wrecked the timetable

It was 20 September 2021
The Siemens units were on the MML and ECML.
Other than that, correct.

I think it's the 9th August 2019 that Ken H is referring to as that was a gas turbine (Little Barford) and wind farm (Hornsea 1) going offline that caused the frequency drop, power cuts and timetable carnage. Important to remember that this was specific to Thameslink (Cl700, but only operating on overhead?)

Ofgem's report (https://www.ofgem.gov.uk/sites/default/files/docs/9_august_2019_power_outage_report.pdf), page 6 and page 8 carry the following commentary:

The most significant impacts on the rail sector occurred, in particular, when certain Govia Thameslink Railway trains shut down and became stranded due to the configuration of their own on-board automatic safety systems, and this caused other services to be cancelled or delayed.

The major impacts of the outage were on services in other sectors, particularly the rail sector, due to the affected providers’ lack of resilience to the disturbance.

But as others have already implied it is important not to conflate renewable variability with faults. There was a similarly significant upset in 2008 when Sizewell B and Longannet (I think) disconnected almost simultaneously leading to widespread power cuts. You never hear renewables sceptics talk about it for some reason, it's a real puzzler.

 

[Ken H]

They do clouds cover solar panels very quickly and they deload. The wind gusts and wanes and the turbines power output adjust accordingly. Thing is with wide dispersal of solar and wind farms across the UK these variations tend to be noise in the background when the system is well loaded. It does become more of a challenge to mange frequency when the system is lightly loaded with high renewable penetration which is why NESO deploys a number of ancillary services to manage frequency. The fast acting services of Dynamic Response and Dynamic Moderations are largely battery provided as they can can act very fast to frequency deviations. NESO determines how much capacity to procure every four hours to match generation mix.


NESO require a minimum of 120GVAs of inertia currently which is considerably reduced from what used to be available from 10yrs ago when the system was dominated by 500MW coal sets. This can be sourced from CCGTs, hydro and the likes of Drax when their generating. They also have five synchronous condensors now installed around the grid. Then there are sources of synthetic inertia like batteries. If the proposed generation mix is insufficient NESO has contracts for interia support and can call on hydro or gas plants to run virtually unloaded but with the spinning mass of the generator.

NESO are revered around the world and our grid is run very conservatively which comes with a cost but thats the price of keeping the lights on.

Thats all how I understand it. but dont tell me its cheap.

 

[N1]

As an aside, has anyone heard more about JET's flywheel energy storage system being repurposed for Grid Inertia? I recall initial proposals being made in 2023 when JET was decommissioned but nothing since. Maybe wasn't viable?

 

[Trainbike46]

As an aside, has anyone heard more about JET's flywheel energy storage system being repurposed for Grid Inertia? I recall initial proposals being made in 2023 when JET was decommissioned but nothing since. Maybe wasn't viable?

How would it be different from a synchronous condenser? Because it does just sound like a synchronous condenser.

 

[N1]

How would it be different from a synchronous condenser? Because it does just sound like a synchronous condenser.

Synchronous condensers operate at zero toque, they have limited mass associated with the rotating shaft. They provide more power factor control than voltage stabilisation. Fly-wheels are the same but have a mass attached to the shaft, operate with torque and provide voltage and frequency stabilisation, and can output power. The inertia mass does not have to be synchronous.

The existing ones at JET were there to provide power to the fusion experiment plasma pulses, as the grid connection to the site wasn't large enough. There are 2 of them and can output 400MW each.

 

[edwin_m]

I think it's the 9th August 2019 that Ken H is referring to as that was a gas turbine (Little Barford) and wind farm (Hornsea 1) going offline that caused the frequency drop, power cuts and timetable carnage. Important to remember that this was specific to Thameslink (Cl700, but only operating on overhead?)

Ofgem's report (https://www.ofgem.gov.uk/sites/default/files/docs/9_august_2019_power_outage_report.pdf), page 6 and page 8 carry the following commentary:


But as others have already implied it is important not to conflate renewable variability with faults. There was a similarly significant upset in 2008 when Sizewell B and Longannet (I think) disconnected almost simultaneously leading to widespread power cuts. You never hear renewables sceptics talk about it for some reason, it's a real puzzler.

The problem was greatly exacerbated because the 700s, or some of them, were configured so when the frequency went out of tolerance they shut down and could only be restarted by a technician with a laptop. I believe they have since been modified so the driver can just "switch off and on again", and if the frequency is back in spec by then they can continue. I'd also query whether the transformer and the electronics actually needs such a tight limit on supply frequency, or if the limit was just set according to some specification that someone decided it should meet. Either way, the disruption to the rail network was much more a problem with the trains than with the grid.

 

[Ken H]

The problem was greatly exacerbated because the 700s, or some of them, were configured so when the frequency went out of tolerance they shut down and could only be restarted by a technician with a laptop. I believe they have since been modified so the driver can just "switch off and on again", and if the frequency is back in spec by then they can continue. I'd also query whether the transformer and the electronics actually needs such a tight limit on supply frequency, or if the limit was just set according to some specification that someone decided it should meet. Either way, the disruption to the rail network was much more a problem with the trains than with the grid.

if the frequency goes out of tolerance there is a risk the harmonincs in the supply will changee frequency to one wich confuses signalling. A/C track curcuits I think. So they fit an intermediate current monitoring unit to the train so if supply frequency is outside spec, it operates themain circuit breaker.

I dont know of any other satety kit that has a turn off like that. Glad to hear of examples

 

[HSTEd]

CCGTs are notorious for being built in a manner that makes them vulnerable to frequency swings.

Far more so than older CEGB era coal and nuclear plant. Indeed, the CEGBs traditional use of steam turbine driven boiler feed pumps madethis considerably less of a problem.

With a synchronous motor boiler feed pump insufficient supply causes the frequency to drop, which then causes the pump to slow down which reduces boiler water feed rate, which can itself cause a fall in boiler steam output and thus turbine output. Significant effort was historically expended to ensure this would not spiral.

 

[edwin_m]

if the frequency goes out of tolerance there is a risk the harmonincs in the supply will changee frequency to one wich confuses signalling. A/C track curcuits I think. So they fit an intermediate current monitoring unit to the train so if supply frequency is outside spec, it operates themain circuit breaker.

I dont know of any other satety kit that has a turn off like that. Glad to hear of examples

Yes I'm aware of that - Reed track circuits and FDM systems are the worst offenders, as a small induced AC current at the wrong frequency and phase could trigger a wrong side failure. I believe more recent stock like the 700 detects this in the traction package software rather than having an independent monitor like older three-phase drives.

Having said that, para 2.4.12 of the report linked in #310 notes a minimum frequency of "below 48.8Hz" during this event, but only (para 2.4.14) for less than 200ms. According to para 2.7 the lower operating limit for the railway is specified as 47Hz but trains are permitted to reduce performance or disconnect below 49Hz. So maybe it was acceptable for the 700s to shut down, although no similar disruption was mentioned to other classes, which must either not have shut down or did so and then recovered. 2.7 also notes that the 700's software was being upgraded for the driver to reset and continue after such an event.

2% deviation of harmonic frequency would be more than enough to push a "safe" harmonic into a dangerous frequency as defined by BR1914 (restricted access, not quoting). So to be able to meet the criteria of working normally down to 98% of nominal supply frequency, the AC traction that generates the harmonics can't use the mains supply frequency as a reference.

 

[Bald Rick]

I think it's the 9th August 2019 that Ken H is referring to as that was a gas turbine (Little Barford) and wind farm (Hornsea 1) going offline that caused the frequency drop, power cuts and timetable carnage. Important to remember that this was specific to Thameslink (Cl700, but only operating on overhead?)

I may well have got my major power events mixed up. Apologies. Trying to remeber what it was in Sept 2021 - I know there were trains stranded and nothing moved south of St Albans.

Yes when the frequency issue happeened, it was only the 700s (and 717s) on AC, presumably because those in DC don’t see any frequency

(well, they do, but only a ripple).

 

[hwl]

I may well have got my major power events mixed up. Apologies. Trying to remeber what it was in Sept 2021 - I know there were trains stranded and nothing moved south of St Albans.

Yes when the frequency issue happeened, it was only the 700s (and 717s) on AC, presumably because those in DC don’t see any frequency

(well, they do, but only a ripple).

The frequency setting on the TCMS on the 700s hadn't been set correctly so the hard shut off was set much tighter than it should have been at the point where reduced power draw should have started.

There is an excellent youtube channel with in-depth content for a UK EHV engineer an in this episode he covers the recent Spanish problems:

The key take away is that the GB network is less vulnerable, lessons having been learnt from August 2019 and that the GB grid still has plenty of improvements in the pipeline in the next few years and potentially more beyond that.

 

[Trainbike46]

Synchronous condensers operate at zero toque, they have limited mass associated with the rotating shaft. They provide more power factor control than voltage stabilisation. Fly-wheels are the same but have a mass attached to the shaft, operate with torque and provide voltage and frequency stabilisation, and can output power. The inertia mass does not have to be synchronous.

The existing ones at JET were there to provide power to the fusion experiment plasma pulses, as the grid connection to the site wasn't large enough. There are 2 of them and can output 400MW each.

Thanks for explaining, that makes sense!

 

[Nicholas Lewis]

Thats all how I understand it. but dont tell me its cheap.

Its not cheap but neither was heating up thousands of gallons of water in a 500MW steam set so it could sit there spinning ready to pick up load. The really crippling costs is the fact that OFGEM has allowed windfarms to be overbuilt in Scotland and frustrated for over a decade NG, SP and SHETL to expand the grid such that we are shelling out over 3B/yr and rising to manage the transmission constraints.

 

[brad465]

Earlier today there was a point where the wholesale price was -£100 per MWh, and that was while we had a sizeable import need, and remained negative even in the peak hours this evening. Love to know what made this possible.

 

[HSTEd]

Its not cheap but neither was heating up thousands of gallons of water in a 500MW steam set so it could sit there spinning ready to pick up load. The really crippling costs is the fact that OFGEM has allowed windfarms to be overbuilt in Scotland and frustrated for over a decade NG, SP and SHETL to expand the grid such that we are shelling out over 3B/yr and rising to manage the transmission constraints.

The CEGB largely abandoned the hot standby pool for steam turbine generators after the miners strikes in the 1960s.

Units were scheduled to start only when there was a reasonable expectation that they would be needed, other sources were used to cover the fast trip load.
Particularly Ffestiniog power station, slack output from hydropower generators requested from the Scottish Hydro boards and the first 160MW interconnector to France.
When gas turbine generators started to become available they were also used in preferance to steam sets in hot standby.

They would also deliberately overrun in-service coal and oil generators to outputs beyond their normal economic output, accepting increases in fuel consumption and extra maintenance burden to do so. (For example, altering the feedwater and boiler feed rates and tolerating increase exhaust losses in the turbine sets)

Ultimately I agree about the problem being one of insufficient power transmission capability to haul the power away from the massive generating capacity in Scotland. But that's what happens when you try to treat generation and transmission systems as separate entities in service of a pseudo-market......

EDIT:

At this point, the only way I can see out of this mess, given the costs and bottlenecks in offshore HVDC links, is to impose a 800-1200kV grid overlay. That would either have to use gas insulated transmission lines (either in tunnel or on the surface) or overhead lines.

Overhead lines are probably a hard sell to the population of the borders but the potential savings in electricity bills are enormous, and if it is not solved, constraint payments are going to strangle the zero carbon energy system in the cradle.

 

[AndrewE]

Have people read https://www.theguardian.com/busines...a-year-gas-fired-stations-removed-from-market

Energy users ‘could save £5bn a year’ if gas plants are removed from market​

Former energy tsar suggests the ‘radical step’ as one of the few options the government has for cutting bills

which talks about the madness that our price is set by the last (most expensive) generation to enter the market as demand peaks.

Separately I have seen discussion that wind generation being curtailed isn't as appalling as it seems at first sight, as it's not much different to gas turbines being paid lots to come in at the last moment...
Agreed though that running gas turbines in the south just because we can't get power from northern windfarms isn't very clever.

 

[jon0844]

The people pushing oil industry narratives won't be mentioning the cost of keeping gas turbines ready, any more than revealing how much it costs to get oil from the ground and ship it, refine it either (or reveal the literal TRILLIONS in subsidies globally).

They want to point out the money lost by not using wind power in any given day, or the impact of mining metals to make batteries - as if oil just comes up from the ground by itself and runs along pipes straight to a fuel pump.

Even when electricity can be negatively priced, as it has been a lot this year, nobody seems to believe that green energy is better than gas - and that it's the green energy being subsidised most.

 

[bspahh]

There are other circumstances where steam will be released from a turbine system other than an unexpected trip.
Especially on the earlier AGR stations, the plants may be running with part of their feedwater system isolated, or having just started up.

This is a story from Usenet from John De Armond

Ballistic drums (John G. De Armond)

From: jgd@rsiatl.UUCP (John G. De Armond)
Newsgroups: rsi.postings
Subject: jgd; rec.models.rockets; Re: A tale of [nuclear] model rocketry
Date: 13 Dec 89 09:36:45 GMT
Lines: 92

In article <37976@ames.arc.nasa.gov> mike@ames.arc.nasa.gov (Mike Smithwick) writes:
>
>Ok guys, you want great model rocket stories? I got great model
>rocket stories. . .

[a GREAT story deleted ]

>Beat that guys!

Hey, with a challenge like that, who could resist Betcha can't
beat this one.

This story involves TRULY internal combustion propulsion - as in internal
to the atom.

The setting is the Sequoyah Nuclear Plant in Chattanooga, TN. The date is
about 1979 or 80 and we're starting that sucker up for the first time.

I was the shift test engineer, running the startup test program on the evening
shift. Most testing is conducted from the control room. In order
to get to the control room, a stroll across the turbine deck is necessary.
This deck contains the huge (1200 MWe) turbines and a variety of support
equipment. The floor is tiled and the 10 story tall walls are slightly
tinted glass. A glorious sight when bathed in the afternoon sun.

As I was strolling toward the control room, I noticed an Aux. Operator
standing near a device called a moisture separator/reheater. This device is a
large heat exchanger, about 40 feet long and 20 feet in diameter. Its
purpose is to reheat the steam exhausting from the high pressure turbine
in order to dry it before being introducted into the low pressure turbines.
On top of this device is a large safety relief valve with a tailpipe
that extended almost 10 floors through the roof. When this valve opens,
steam at about 900 psi exhausts to atmosphere through this ~36" tailpipe.
The tailpipe is hung from spring hangers and simply floats on the exhaust
flange of the safety valve which allows the pipe to move under
thermal expansion.

Anyway, this operator was standing along side the reheater. In one hand
was a walkie-talkie and in the other hand was a lanyard that ran to the
manual trip lever on one of the safeties. This was not unusual, as the
functionality of these critical valves is tested fairly often. Normally
when the valve trips, there is some steam escaping around the valve, a
loud shreik and a large steam cloud on the roof.

As I was almost to the control room, the operator got some activity on
the handi-talkie and pulled the manual trip lanyard. The noise
from the H-T had gotten my attention and I looked around just in time
for the valve opening. FOOOMsssss!!!! The whole damn tailpipe jumped
up about 6 inches in the air before settling back down.

Since this behavior was quite abnormal, I asked the operator what was
going on. He pointed to the elevator and suggested I go to the roof
to find out. I rode the elevator 5 floors and hoofed it up 5 flights
of stairs and onto the roof. I noticed about 10 guys standing around
near the tailpipe.

As I stepped out, I saw about 6 guys hoisting A 55 GALLON DRUM up and over
the tailpipe. Whoosh. It hit bottom 10 floors below.

A message on the handi-talkie and BOOOMssss!!!!!!!! That damn 55 gallon
drum full of 600 pounds of water had been launched literally out of sight
by 900 psi of steam.

It stayed out of sight a good 30 seconds before it came into view again,
hurtling down over the Chickamauga lake. When it hit the lake, it looked
like a depth charge going off.

I did a 180 degree twist and headed back down the stairs as fast as my
little feet would carry me. As Shultz on Hogan's heros used to say,
"I saw notsing.. I hear notsing.. I know notsing..". I did keep
a piece of strip chart recording that showed the dip in steam pressure
that documents the launch

I heard a few days later that one of their ICBD (Inter County Ballistic
Drums) had been caught by a gust of wind and had come down on a car in
the parking lot, thus ending the era of the nuclear powered missile.
The funny thing is, no one would ever admit to knowing how that drum
ended up on the car, which ended up about 6 inches tall

So if anyone asks if America has ever launched a nuclear powered
missile, you can answer truthful YES!

[BTW, I've waited 10 years to tell this story to ensure that my
memory of the names of those involved has thoroughly faded just in
case the nuke police were to get interested.]


John

 

[Nicholas Lewis]

Have people read https://www.theguardian.com/busines...a-year-gas-fired-stations-removed-from-market

which talks about the madness that our price is set by the last (most expensive) generation to enter the market as demand peaks.

Separately I have seen discussion that wind generation being curtailed isn't as appalling as it seems at first sight, as it's not much different to gas turbines being paid lots to come in at the last moment...
Agreed though that running gas turbines in the south just because we can't get power from northern windfarms isn't very clever.

That article is half correct. Firstly only about 60% of daily energy used goes through the day ahead market which is where marginal pricing applies. The other 30% is run through the forward markets on fixed priced PPA contracts and this is largely renewables selling to companies or wholesalers who want to improve green credentials. The market is being distorted by excess generation in Scotland on windy days and NESO needing to constrain it off and replace it with gas. This is the expensive generation referred to in the article but it’s a small part of overall output and will still be required until the new DC Eastern Green links are commissioned in 29/30. The biggest issue here is market design in that wind farms are incentivised to run despite transmission constraints and the gas plants sit there used less and less in continuous running so they cost more when called on at short notice and for only a few hours. So proposal has some merit but given renewables will still receive their FiT, ROC and CfD payments in additions to merchant power price I doubt savings will be that much but article lacks detail on assumptions. Anyhow just putting all the blame on gas is misleading.Now zonal pricing has been parked and REMA back in the melting pot they do need to come up with something better but don’t think for one minute the renewables owners won’t push back as they also benefit hugely from gas setting the price.

 

[HSTEd]

. The market is being distorted by excess generation in Scotland on windy days and NESO needing to constrain it off and replace it with gas. This is the expensive generation referred to in the article but it’s a small part of overall output and will still be required until the new DC Eastern Green links are commissioned in 29/30. The biggest issue here is market design in that wind farms are incentivised to run despite transmission constraints and the gas plants sit there used less and less in continuous running so they cost more when called on at short notice and for only a few hours.

The problem is the wind programme is still growing rapidly, so constraint payments will likely still be running to billions even once the HVDC links are complete - even if they actually complete by the 2030 target.
Constraint payments are running to several billion pounds per year - which is a significant portion of the total cost of operating the electricity system.

Undersea HVDC has physical limits in terms of output that will prevent it solving this problem on any reasonable time frame. Only on-land transmission can really solve this mess.

 

[Class 317]

The problem is the wind programme is still growing rapidly, so constraint payments will likely still be running to billions even once the HVDC links are complete - even if they actually complete by the 2030 target.
Constraint payments are running to several billion pounds per year - which is a significant portion of the total cost of operating the electricity system.

Undersea HVDC has physical limits in terms of output that will prevent it solving this problem on any reasonable time frame. Only on-land transmission can really solve this mess.

The rapid deployment of BESS systems will start to eat away at curtailment payments over the next few years. Quite a few large ones are planned in Scotland as well as Northern England.

I believe it's being discussed for the next auction round to reduce curtailment payments for new renewable generators in a bid to encourage co location with BESS or other energy storage systems to make most use of new grid connections. Essentially a wind operator would store excess at times of over supply but supply it from the BESS at times of under supply. Payments would need to be structured right to get this outcome.