UK Wind-Generated Electricity on a fairly windy night

[JohnW2]

Exactly, and importing extra from the countries around us to help with the energy shortfall.

Not much, though. This (current) is reasonably typical, although it's more normal for us to be importing 1%-2% of our demand from France, rather than exporting to France, which we are currently doing ...

Kind Regards, John

 

[JohnW2]

From the meter displays it's evident that the 'constant' is the nuclear supply at 5GW. The data table suggests a nominal system demand (supply) of >20GW. It would therefore make sense if the system supply base demand was met by an increase in capacity of the nuclear system to somewhere around 15GW.

Totally agreed - however, see what I have just written to Harry about increasing nuclear generation capabilities - i.e. "don't hold your breath"!

Kind Regards, John

 

[JohnW2]

... I hope that if tidal, or wave power, comes on stream in a meaningful quantity we will use even less gas.

I don't know if we have any in service, yet, but it's clearly not enough for it to appear in the Gridwatch data at all!

The one element I am a bit 'suspicious of is this ...

... which regularly accounts for 5-10% of our de. As I understand it, this relates to the burning of imported 'timber' (I think mainly as 'chippings'), in at least some cases in converted coal-fired facilities. What I don't know is the extent to which the 'products of combustion' are captured/cleaned - and, of course, the import process (I think a lot from Canada) itself brings its own environmental cost.

Kind Regards, John

 

[Harry Bloomfield]

So would I. However, our current nuclear capability is essentially running 'flat out', continuously (i.e,. 24/7, every day) - and it seems that increasing that capacity takes many years and lots of discussion/enquiries/protests/politics/whatever.

Well if they do intend to continue with the EV's and the GSHP and ASHP - we need cheap reliable power sources as a matter of urgency.

 

[Harry Bloomfield]

... which regularly accounts for 5-10% of our de. As I understand it, this relates to the burning of imported 'timber' (I think mainly as 'chippings'), in at least some cases in converted coal-fired facilities. What I don't know is the extent to which the 'products of combustion' are captured/cleaned - and, of course, the import process (I think a lot from Canada) itself brings its own environmental cost.

Lookup Drax. They were adding capture a while ago.

It has changed a lot since I was last in there.

 

[JohnW2]

Not much, though. This (current) is reasonably typical, although it's more normal for us to be importing 1%-2% of our demand from France, rather than exporting to France, which we are currently doing ...

I should perhaps have added that I have to assume that there is some 'commercial' and/or 'political' (rather than sensible/common-sense) reason why we are nearly always importing at least some electricity from France, Holland, Norway, Belgium etc. (particularly France) even at times of relatively low UK demand.

Kind Regards, John

 

[Harry Bloomfield]

I should perhaps have added that I have to assume that there is some 'commercial' and/or 'political' (rather than sensible/common-sense) reason why we are nearly always importing at least some electricity from France, Holland, Norway, Belgium etc. (particularly France) even at times of relatively low UK demand.

Possibly, but I don't know the reason, unless it might be cheaper to import than generate at home.

 

[JohnW2]

Lookup Drax. They were adding capture a while ago.

Thanks. Yes, I was aware of Drax (and the technology) but, as I wrote, I don't know to what extent they are currently capturing carbon (and other pollutants) from their emissions.

Kind Regards, John

 

[JohnW2]

Possibly, but I don't know the reason, unless it might be cheaper to import than generate at home.

As I said, I presume it must be commercial/political/whatever - because we know, from our current ability to service high demand periods (with little import) that we could, if we wished, service lower demand periods without the need for any import.

Edit: "cheaper to import than generate at home" would, of course, be a 'commercial' reason for importing. Does anyone know what is the (electrical) 'efficiency' of the international movement of electricity (i.e. how much is 'lost', in heating the English Channel or inverters/transformers etc.)?.

Kind Regards, John

 

[JohnW2]

Well if they do intend to continue with the EV's and the GSHP and ASHP - we need cheap reliable power sources as a matter of urgency.

We do.

The corollary of that would seem to be that if we do not 'urgently' acquire substantial additional "cheap reliable power sources" then, no matter what 'we' (particularly the government) might want/hope, we would not be able to "continue with the EV's and the GSHP and ASHP" to the extent and/or speed that 'we' hope/intend.

Kind Regards, John

 

[bsr]

Hi

I can try to help:

• As above, wind turbines are feathered in gales due to the potential of gusts to shock load and damage the gearboxes and bearings.
• Nuclear power is currently on the decline with all bar one of the existing UK fleet to shut down by 2030, half will have shut down by the end of next year https://www.edfenergy.com/energy/nuclear-lifetime-management .
• One new nuclear plant is planned for 2027 and another for about 2032. Each is 3.2GW so replaces three of the old reactors.
• There is nearly 30GW of wind in the UK but this typically only works at 30% load factor. Government is aiming for 40GW by 2030 and 100GW by 2050.
• Lots of people are quietly very worried about keeping the lights on 2024-2027
• Expectation is that EVs not an issue provided demand shifting is used ie charging overnight.
• Most imported energy over the interconnector is French nuclear so low carbon.

 

[Harry Bloomfield]

Hi

I can try to help:

• As above, wind turbines are feathered in gales due to the potential of gusts to shock load and damage the gearboxes and bearings.
• Nuclear power is currently on the decline with all bar one of the existing UK fleet to shut down by 2030, half will have shut down by the end of next. year https://www.edfenergy.com/energy/nuclear-lifetime-management .
• One new nuclear plant is planned for 2027 and another for about 2032. Each is 3.2GW so replaces the of the old reactors.
• There is nearly 30GW of wind in the UK but this typically only works at 30% load factor. Government is aiming for 40GW by 2030 and 100GW by 2050.
• Lots of people are quietly very worried about keeping the lights on 2024-2027
• Expectation is that EVs not an issue provided demand shifting is used ie charging overnight.
• Most imported energy over the interconnector is French nuclear so low carbon.

Thanks and yes, that is very helpful - but it fails to explain what we will do when the wind fails to blow?

 

[JohnW2]

Hi, I can try to help:

Many thanks. Very helpful. - I'm gradually learning

As above, wind turbines are feathered in gales due to the potential of gusts to shock load and damage the gearboxes and bearings.

Fair enough. Do all very strong winds count as situations likely to result in potentially damaging gusts, or are there some meteorological circumstances in which 'partial feathering', such as I speculated about, can be utilsed?

Nuclear power is currently on the decline with all bar one of the existing UK fleet to shut down by 2030, half will have shut down by the end of next year https://www.edfenergy.com/energy/nuclear-lifetime-management . .... One new nuclear plant is planned for 2027 and another for about 2032. Each is 3.2GW so replaces three of the old reactors.

I didn't know the details, but that's roughly what I understood. Even 2032 is quite a long way away, but is it the case that there are currently no definite plans for anything new beyond 2032 - and, if so, what is the earliest one might realistically expect that we could see the 'next' (after 2032) one come on-line (assuming someone fairly soon decides to 'plan' it)?

There is nearly 30GW of wind in the UK but this typically only works at 30% load factor. Government is aiming for 40GW by 2030 and 100GW by 2050.

This is presumably a basket into which one must not put too high a proportion of one's eggs, since there are bound to be some significant periods during which there is little/'no' significant wind?

Lots of people are quietly very worried about keeping the lights on 2024-2027

That doesn't surprise me. As I often recall, even before we thought/heard anything about EVs, many were expressing concerns about the adequacy of UK generating capacity to service demand as we moved forwards, particularly as nuclear plants came to the end of their lives (with, at the time, seeming little planning for replacements). The move towards EV and 'heat pumps' has got to make that worse.

Expectation is that EVs not an issue provided demand shifting is used ie charging overnight.

I suppose that is sort-of what I've been suggesting - although, as I've said, it presumably would require some specific active control over the chargers, not the least to avoid (as has been suggested) a lot of EV charging starting during the currently highest demand period in the early evening. What about the proposed move from gas heating to ASHPs and GCHPs - is there an expectation that that could become an 'issue' (in combination with EV charging)?

Most imported energy over the interconnector is French nuclear so low carbon.

Are you saying that that is the reason why we import French electricity even when we have the capacity (hence always take as much electricity from France as thjey are able to provide)? Do you know the answer to the question I recently posed about the efficiency (or otherwise!) of these international transfers of electricity?

Kind Regards, John

 

[SimonH2]

but would I be right in thinking that that will be partially compensated by the fact that, in the UK, cooler weather tends to be associated with more wind?

Well, yes there is some correlation between the cooler times of year and "quantity of wind", but in terms of the extremes that need to be catered for, the coldest weather is typically very low in wind. Look back to December 2010 for an example - static high pressure over the UK (and IIRC, a lot of Europe) leading to naff all wind and exceedingly cold weather. Round here, it barely got above freezing during the day for a fortnight, and was well below freezing overnight. So at least a couple of weeks when ASHPs would mostly be as useful as a chocolate teapot and drawing massive currents due to reduced efficiency - at the same time as windmills being pretty well useless.

Agreed, there is an 'optimum', rather than 'the more the better'.

Yes, each turbine has an optimum wind speed (or range of speeds). Work by some clever aerodynamics experts has progressively widened these ranges over the years so modern mills have wider operating wind speed capabilities. Also, while many earlier mills had synchronous or induction generators and rotor speeds coupled directly to grid frequency, these days they use power electronics so the rotor speed can be coupled to the wind speed which massively increases the useful wind speed range.

I don't know how they do this, but I would have thought that it would be possible to 'partially feather' the blades when wind was very strong, so that they could function close to their 'maximum safe capability', without risk of damage. Is that not the case?

Again - it depends
Fixed blades are simpler and cheaper - both to build and to maintain. Adjustable blades are more complicated, cost more, and have higher maintenance costs. Also, it's not as simple as just turning the blade to match wind speed. If you look along a blade, you'll see a lot of twist - a "flat" blade at the tips which twists over the length until it had quite a high angle from the disk plane at the blade root. Easy to understand - the tip of the blade is moving faster than the root, so it needs a flatter profile to see the same angle of attack relative to the air flow.
It doesn't take much imagination to realise that the twist in the blade is only optimum for one ratio of rotor speed to wind speed. In extreme, it's possible to feather a blade such that parts of it (probably the root) have a negative angle of attack and hence act to brake the rotor rather than drive it.
And as mentioned above, these days with cheap high power electronics, there's no longer a need to keep the rotor speed constant - hence it can be varied (without feathering the blades) to keep the angle of attack at it's optimum. There's a limit to this - blade forces go up (linearly) as rotor speed does, and if the tips go supersonic then noise increase dramatically, and you can get some "interesting" effects.

There's a small wind farm near here where I've been able to go up and have a look around - organised trip with a local engineering society. These are quite old now, small fixed blades, induction generator. When wind speed exceeds a certain level then they have to shut down (which is automatic) - firstly to avoid overloading the generator (and drive chain), and secondly to protect the rotor. This particular design has an outer section of blade that can "pop out" when released, and twists about 90˚ when it does - thus acting as a very powerful air brake. Once the rotor speed is low enough, a mechanical disk brake takes over and locks the rotor.
As an aside, there's a minimum speed below which they generate less power than the ancillaries (e.g. lub oil pumps etc) take - so better to just shut down and shut down the ancillaries.

I continue to be fairly 'impressed'. Now at roughly the peak demand time of day (6pm, total demand = 36.5 GW), wind generation is still slightly ahead of gas ..

We have a steady 'blow' at the moment throughout the UK, strong wind, but not too strong, so pretty well ideal conditions - yet we are still having to call up gas generation. I am not as impressed. Now if the deficit were made up by nuclear, I really would be impressed.

And that highlights one of the problems. It's mostly CCGT that's doing the hard work of matching supply and demand. As the amount of wind capacity goes up, it has a double whammy on the other generators : the bottom of the troughs gets lower, and the variation in demand increases. The operating costs of a gas turbine increase dramatically when following a widely varying load. Thermal cycling takes a huge toll, with stress cracking of the turbine being a big problem - to add some scale, with even a "small" turbine, if you take the upper half of the casing off and put it on the floor, then you can literally walk through it (another organised visit by the local engineering society). And of course, not only is the operator being told to run the machine in the most damaging operating regime possible - he's only getting paid for a relatively small amount of electricity. As a result, many operators have simply shut down, and others have only stayed open due to being given availability payments.

However, our current nuclear capability is essentially running 'flat out', continuously (i.e,. 24/7, every day) - and it seems that increasing that capacity takes many years and lots of discussion/enquiries/protests/politics/whatever.

China has proved that you can build nuclear plants on-time, to budget, and in relatively short timescales. Of course, part of that is not holding lengthy public enquiries, catering to every minority pressure group, etc, etc. Their approach being that "the government" decides what's going to be built, when, and where - and the population simply accepts it or finds themselves in trouble.
But from a talk a few years ago from an industry expert, I gather they were putting up (IIRC) Westinghouse AP1000 systems in around 5-6 years from cutting turf to producing power - with several in progress at the time.

Most imported energy over the interconnector is French nuclear so low carbon.

That's a "disingenuous" description of the sort usually used by various factions of the green lobby.
Just like over here if taken in isolation, if we import power from France, then that nuclear generated power can't be supplying someone else. So somewhere on the continent there will be another power station opening the taps. That could well be in somewhere like Poland where I believe they still burn a lot of coal. The ONLY time that's not the case, and the power can truly be described as low or zero carbon, is when there is no fossil fuel plant running anywhere on the connected grid and renewables or nuclear would be getting an instruction to reduce output. The European grid is a loooooooong way from that, so it's disingenuous at best to be saying that we import "French nuclear" and it's low/zero CO2.

 

[Harry Bloomfield]

And that highlights one of the problems. It's mostly CCGT that's doing the hard work of matching supply and demand. As the amount of wind capacity goes up, it has a double whammy on the other generators : the bottom of the troughs gets lower, and the variation in demand increases. The operating costs of a gas turbine increase dramatically when following a widely varying load.

That is the part which really winds me up, having to build and match the capacity of wind, with conventional plant ready to pick up the load, when wind fails us. To be genuinely green, we need much more than enough wind capacity, enough to be able to store a massive surplus, but storage in the UK has it's own insurmountable issues.

Thermal cycling takes a huge toll, with stress cracking of the turbine being a big problem - to add some scale, with even a "small" turbine, if you take the upper half of the casing off and put it on the floor, then you can literally walk through it (another organised visit by the local engineering society). And of course, not only is the operator being told to run the machine in the most damaging operating regime possible - he's only getting paid for a relatively small amount of electricity. As a result, many operators have simply shut down, and others have only stayed open due to being given availability payments.

I once had a photo of my car, parked under the upper shell of a turbine at Ferry Bridge C, when they had number 2 stripped down, whist I was there adding new instrumentation to the start and standby pumps.

China has proved that you can build nuclear plants on-time, to budget, and in relatively short timescales. Of course, part of that is not holding lengthy public enquiries, catering to every minority pressure group, etc, etc. Their approach being that "the government" decides what's going to be built, when, and where - and the population simply accepts it or finds themselves in trouble.

That was the approach the UK used to take, when the UK used to make some progress in the world

Thanks for that informing summary, greatly appreciated.