The Future of Power Generation in Great Britain

[NJH]

Fixed site energy storage.

History has a habit of repeating itself, I can remember when this was supposed to be the next big thing:
http://www.google.com/patents/US6150742

I wonder what happened to all their research.

[WatchfulEye]

NJH said:

Fixed site energy storage.

History has a habit of repeating itself, I can remember when this was supposed to be the next big thing:
http://www.google.com/patents/US6150742

I wonder what happened to all their research.

This type of energy storage is in widespread use where short-term energy storage (seconds) is required, as it is cheaper than batteries.

These flywheel systems are deployed on the London Underground to support traction voltage during acceleration (improving train acceleration, without the need to reinforce the grid supply), and provide a sink for reverse power during regenerative braking (increasing the proportion of energy which is recoverable). Although most are single flywheel type systems, there are some concentric systems on offer, where the inner flywheel is synchronous with the grid frequency, and a magnetic "clutch" can be used to couple the faster spinning outer flywheel to the shaft, and therefore deliver energy to it.

They are also increasingly being deployed in data centre and hospital UPS systems in place of batteries, due to lower maintenance and capital costs. Batteries are not ideal when you only need to support the load for 15 seconds until generators start.

Edited by WatchfulEye on Sunday 6th August 16:20

[Gary C]

WatchfulEye said:

eliot said:

Tech question please;

Why are furnaces sensitive to frequency? Surely that's a pretty 'dumb' load that just needs grunt rather than a nice clean precise 50hz supply.

What other loads are sensitive to frequency - the only obvious ones to me would be electric motors, what critical effect would 1/2hz drop actually cause? (i know it rotates slower, but is that really the end of the world?)

IT equipment all uses swiched mode power supplies - so I can't see how a variation in frequency would make any difference?

Finally - you mentioned dump tubes, can I assume that this sort of alleviates back pressure allowing the turbine to spin faster to correct frequency?
..

I don't think the furnaces are sensitive to frequency, but they are huge loads, and are tolerant to power loss. As a result, they are commonly fitted with low-frequency load-shedding controls, so that they disconnect automatically in the event of a large grid imbalance. However, if the trip system operates too frequently, the disruption to business and loss of production may be intolerable to the furnace operator.

Frequency sensitive loads are basically rotating machines. Motors and generators. For most purposes a 1% drop in speed (0.5 Hz) may be acceptable. However, very large machines, such as multi-MW motors may have vibrational resonance close to, but not exactly, 50 Hz. Similarly, large turbine generators have a similar property, in fact, it is often worse due to the large number of connected rotating components (turbine discs of various diameters, etc.), hence operating a turbine off-frequency while under load is highly inadvisable (typical limits might be +/- 1% indefinitely, down to 1 second at +/- 6%).

There are also some secondary effects on power generators. New designs of CCGT generators tend to use a single shaft synchronous design, rather than a free power turbine. A drop in frequency will therefore reduce the speed of the compressor, and therefore reduce the air flow and therefore power output. For AGR plants, as said above, the gas circulators may be synchronous. If the mains frequency falls, the circulators slow, the core temperature rises due to reduced coolant flow, doppler effect from the core temperature alters the interactions between neutrons and uranium atoms causing the chain reaction to falter and reactor power output to fall.

The dump tubes allow steam to bypass the turbine, and go straight to the condensers. Under normal operation, the bypass valve would be closed, and all steam would go to the turbine. However, if frequency instability is anticipated, some of the steam would be diverted to the condensors instead of the turbine. This would reduce turbine output, which would need to be made up by another plant. However, in the event of a sudden drop in frequency, a reserve is available, by bringing the steam currently going to the condensor and diverting it back to the turbine. This allows the plant to respond to changes in grid condition, without allowing the reactor to operate in steady-state at full power, unaffected by the change in electrical power output.

Can't remember the details, but they were worried about loosing a large furnace which if it's allow to cool means the refectory cracks and it costs a fortune to fix and ngc had some lability at the time. I think they had large synchronous fans ? Rather than pure electric arc ? I'm not a furnace expert, just that ngc got so worried, they started to threaten action under the grid code. We spent millions installing dump tubes and associate plant that in the end never got used. However it was the commissioning of sizewell b that seemed to bring it to a head as a single reactor trip means the loss of ~1.21GW in an instant .

As to the tech of agr's, the slowing of the gas circulators reduces gas flow, therefore the reactor temperature rises yes, but what them happens is the control system inserts th rods to reduce power, which means less heat energy to the boilers which means steam temperature falls, so the control system reduces feed flow, which means less steam to the turbine and less electricity.

[NJH]

WatchfulEye said:

NJH said:

Fixed site energy storage.

History has a habit of repeating itself, I can remember when this was supposed to be the next big thing:
http://www.google.com/patents/US6150742

I wonder what happened to all their research.

This type of energy storage is in widespread use where short-term energy storage (seconds) is required, as it is cheaper than batteries.

These flywheel systems are deployed on the London Underground to support traction voltage during acceleration (improving train acceleration, without the need to reinforce the grid supply), and provide a sink for reverse power during regenerative braking (increasing the proportion of energy which is recoverable). Although most are single flywheel type systems, there are some concentric systems on offer, where the inner flywheel is synchronous with the grid frequency, and a magnetic "clutch" can be used to couple the faster spinning outer flywheel to the shaft, and therefore deliver energy to it.

They are also increasingly being deployed in data centre and hospital UPS systems in place of batteries, due to lower maintenance and capital costs. Batteries are not ideal when you only need to support the load for 15 seconds until generators start.

Edited by WatchfulEye on Sunday 6th August 16:20

Thanks that's some interesting info.

What about high capacity systems?

Batteries are also increasingly being replaced by super-capacitors.

[WatchfulEye]

NJH said:

Thanks that's some interesting info.

What about high capacity systems?

Batteries are also increasingly being replaced by super-capacitors.

Higher capacity systems are being developed, but flywheels aren't ideal for this. In terms of £/kWh flywheels are poor value for money. However, in terms of £/kW for short-term charge/discharge, they are good value.

There has been deployment of a number of grid scale battery storage systems, as part of a pilot project for national grid known as "enhanced frequency response", where NG have been looking for alternative technology solutions for instant responding supplementary power. These projects have mostly used lithium batteries, as far as I can remember. The idea is that they are capable of providing 15-30 minutes of power in response to a drop in grid frequency with no lag time.

There are other potential uses for battery storage. One is for local grid management purposes. Installation of new power lines is expensive and time consuming, and often the new lines are only needed for peak demand which is a few dozen hours per year. Commissioning a multi-million £ power line, which may require a 10 year planning review period (and may still be rejected if required in a heavily built up area) to satisfy demand for only a few hours per year, is not cost effective. In this case, battery storage has a role, and there have been a few deployments for this use.

This type of short-term storage is mainly for grid management purposes - for example, a large power plant trips, and fast-start gas turbines can only guarantee connection and full-load operation within 15 minutes. Traditionally, these services have been provided by a combination of "fast reserve" and "short term operating reserve". Plants offering "fast reserve" to national grid, are capable responding to a demand for power from NG within 2 minutes of request; typically, this would be plants like Dinorwig who just need to open the sluice gates, or gas turbine plants which are operating at less than full load, and have spare capacity immediately available (or increasingly fast-start diesel generators). "Short term operating reserve" is much the same but requires response within 15 minutes (so this would be things like fast-start gas turbines and fast-start diesel generators).

One thing NG which may appear in potential future tenders for EFR, is whether the plant can provide "inertia services". Most large generators are "synchronous" which means that the rotation of the rotor is mechanically locked to the grid frequency. In the event of supply/demand imbalance, kinetic energy of the rotating machinery acts as a buffer to change in frequency. One of the problems with inverter based or asynchronous machines (like PV and wind turbines) is that they offer no inertia. This means that the same imbalance in supply/demand results in faster deviations in grid frequency, and in turn, unless faster frequency response services are provided, the amplitude of frequency deviations may increase.

The latest generations of wind turbines offer software generated inertia - in response to a drop in grid frequency, the electronics will brake the turbine rotor drawing on its kinetic energy to deliver a burst of power into the grid. Because the response is entirely software generated, it can be precisely tuned to the grid behaviour and optimised to minimise frequency deviations; subject to the constraints of finite rotor kinetic energy, and the fact that slowing the rotor below its optimal speed may result in a longer-term reduction in power output.

There is increasing interest in using batteries and capacitors for inertia services, because modern plants of all types tend to have less inertia, and there are increasing periods when large fractions of power are being supplied from inertia-less sources (PV, older wind, interconnectors). One thing to bear in mind is that because wind turbines already contain all the inverter and grid interface technology to provide a software controllable grid-interactive power supply, coupling in an additional energy store in the form of capacitors or batteries makes sense, because much of the required plant is already present.

[ruggedscotty]

WatchfulEye said:

NJH said:

Fixed site energy storage.

History has a habit of repeating itself, I can remember when this was supposed to be the next big thing:
http://www.google.com/patents/US6150742

I wonder what happened to all their research.

This type of energy storage is in widespread use where short-term energy storage (seconds) is required, as it is cheaper than batteries.

These flywheel systems are deployed on the London Underground to support traction voltage during acceleration (improving train acceleration, without the need to reinforce the grid supply), and provide a sink for reverse power during regenerative braking (increasing the proportion of energy which is recoverable). Although most are single flywheel type systems, there are some concentric systems on offer, where the inner flywheel is synchronous with the grid frequency, and a magnetic "clutch" can be used to couple the faster spinning outer flywheel to the shaft, and therefore deliver energy to it.

They are also increasingly being deployed in data centre and hospital UPS systems in place of batteries, due to lower maintenance and capital costs. Batteries are not ideal when you only need to support the load for 15 seconds until generators start.

Edited by WatchfulEye on Sunday 6th August 16:20

Flywheels are not the solution in critical systems, they may be of use in the tube system when reinforcement is needed, providing rotating mass to the system would allow the supply to be maintained by pumping energy into the system when the load drops the voltage, thus maintaining voltage and providing for the increased demand.

However using flywheel UPS for the support of critical supplies isnt to be recommended on several fronts. A UPS can be rated to support a critical load for 30 mins or more. This is a fair chunk of energy indeed. Power outages take many forms, quick transients, micro dips frequency deviations as well as your common power cut. If you use a flywheel and you have a series of dips then each time you are lifting energy from the system slowing down the flywheel. that flywheel needs juice to get the speed back up. it doesnt bode well and if you get an issue with the generator syncronisations if using more than one set to supply the load then you could have a real issue. Batteries provide that stop gap and let you cover many of the eventualities until the generators start and take the load. Flywheels dont. they let you take some of the hit before starting the generators, they provide significant backfill for small outages and supply disturbances.

Ive seen situations where flywheel UPS are being used be caught out and the critical load dropped.

[LongQ]

King Island in the Bass Strait off Tasmania has Wind turbines, a little solar, diesel generators, a flywheel and a resistor together with a large battery installation (the second battery to have been in stalled there) plus demand management and is an active experiment in renewable self sufficiency. The diesel is, or was, intended to be bio-diesel although that seems to have been abandoned after trials.

http://www.kingislandrenewableenergy.com.au/


The link page has a display that is, nominally, a near real time graphic for generation and usage of the system. It used to be quite interesting to watch for a while although when I have run a spot check now and again in recent months (probably about a year now) I have never seen the numbers change and it seems the default graphic is all that is being offered. Normal service had the numbers and graphics changing constantly.

It's a shame that it seems to have been abandoned since the observations were quite instructive.

[hidetheelephants]

Gary C said:

Do you mean fusion ! If so

Cause we can't make it work "

If you mean fission, then, people don't like it, it is expensive, and it takes years to build anything.

A nuclear power station has become such a emotive thing. We can't pretend anymore that it's perfectly safe.

By any objective measure nuclear power is about the safest means of generating electricity available.

Gary C said:

They are very expensive to build and maintain.

How expensive is expensive? The overnight costs are pretty good.

Gary C said:

Small modular reactors may be the answer but maybe a terrorists dream having lots of little ones dotted around the country, where standards slip and regulators become massively stretched trying to keep on top of them all.

Also, security of fuel supplies and costs, now if we went fast breeder, we have enough depleted uranium to last years, but they cost a fortune in backend costs reprocessing the fuel to extract the plutonium.

There's reasonable evidence uranium can be extracted from seawater, so security of supply worries don't mean much even if Australia decided the UK is no longer a suitable customer. The high costs of reprocessing are mostly as a result of solid fuel handling/processing; liquid salt fuel eliminates most of those expensive processes.

Gary C said:

Thorium reactors are interesting, but we need to spend a LOT of money researching an designing and companies are not interested in spending, needs a government to do that.

What's a lot? Collectively there's been over £100bn invested in plant erected in the UK that's good for perhaps 4GW of non-despatchable power, that's a lot.

Even conservative estimates put a FOAK commercial scale MSR as less expensive than EPR on a £ per watt basis; the more adventurous/risky concepts may be far cheaper, the private ventures willing to offer an estimate price a first reactor at $0.5-1bn. It's impossible to quantify costs further without some considerable effort and expense in research, fortunately the chinese aren't fussy about such things and are spending perhaps $100m a year on finding out. Commerce has never been interested in developing nuclear power, only being paid to build it, as the payback period is far too long.

Gary C said:

Just wish we would stop burning all that gas just to make electricity.

Oh well, time to go to sleep, on nights in charge of a nuclear power station tonight

[turbobloke]

Letter to the Editor (Telegraph):

Sir - The Digest of UK Energy Statistics covering 2016 has just been released. Wind generation fell by 7.3%, even though the number of wind turbines rose by 13%. Hydro generation fell by 14%, even though the number of small hydro schemes rose by 20% Luckily, gas rose from 29% of the total to 42% to fill any gaps.
Geoff Moore Alness, Ross-shire

[turbobloke]

From chris watton in another thread,

When the Power Goes Out, So Does Civil Society

Eric Worrall (who he is matters not): "How important is reliable power? Australia seems to be suffering more blackouts recently, as coal plants are decommissioned and shiny renewable installations fail to deliver. Trendy urbanites are starting to notice."

[Tony Wright works for the Sydney Morning Herald, and regularly champions green perspectives. This is him - trendy urbanite]

"You don't need to be one of those wild-eyed doomsday preppers who bury steel containers in their backyards and fill them with canned food to recognise we're a stalled power plant away from chaos."

"The power went out at our house and across our suburb around dinner time on Wednesday. Outside, neighbours returning home sat in their cars in a street as dark as a tomb, their garage doors refusing to answer their electronic clickers. We searched for candles with the light of mobile phones, discovering only that we’d burned them to nothing at dinner parties. We weren’t prepared for this return to an unfamiliar era at all."


It's merely practice for the return to a localised medieval society. Coming soon (2050) to a country near you, courtesy of inadequate renewables and the gullible politicians who are ignorant about their dystopian dreamworld and so remain willing to sleepwalk society into a nightmare.

[V8 Fettler]

Paddy_N_Murphy said:

V8 Fettler said:

Your bizarre response confirms that 5% is probably a reasonable estimate.

My response was that I don't give it a thought as to whether you are annoying.
apologies if the quote was lost on you.



My original comment was and still relevant - you are asked :

V8 Fettler said:

"What is the minimum utilisation ratio for offshore to date? This can be used as an indicator of the capacity of the required back-up systems."

You are giving % answers, which don't help anyone give volume, and you are basing it on "now" which is also pointless as we have established the rate of growth in the power generation makes the 'now' irrelevant (not withstanding the thread title).
Most (all?) on this thread haven't a clue of the volume out there, nor coming.

So these are surely more relevant to what you query of "capacity of the required back-up systems".


When any information is offered, it dismissed or accused of politicking because it doesn't agree with personal opinions.
That is not my concern at all.

In the absence of any meaningful data from you, we'll use the 5% minimum utilisation ratio.

With a broadbrush: if renewables are to dominate power generation in the UK with minimal back-up, then this only really works with total wind generation capacity of at least 600GW+ over a wide geographical area (to achieve 30GW in the worst case scenario), 600GW+ is unlikely, therefore back-up is essential and should be costed in.

How much back-up? 30GW perhaps? Are there fixed and variable costs available per GW of diesel plant or open circuit gas turbine?

Alternatives include rationing and grid collapse.

[wc98]

turbobloke said:

From chris watton in another thread,

When the Power Goes Out, So Does Civil Society

Eric Worrall (who he is matters not): "How important is reliable power? Australia seems to be suffering more blackouts recently, as coal plants are decommissioned and shiny renewable installations fail to deliver. Trendy urbanites are starting to notice."

[Tony Wright works for the Sydney Morning Herald, and regularly champions green perspectives. This is him - trendy urbanite]

"You don't need to be one of those wild-eyed doomsday preppers who bury steel containers in their backyards and fill them with canned food to recognise we're a stalled power plant away from chaos."

"The power went out at our house and across our suburb around dinner time on Wednesday. Outside, neighbours returning home sat in their cars in a street as dark as a tomb, their garage doors refusing to answer their electronic clickers. We searched for candles with the light of mobile phones, discovering only that we’d burned them to nothing at dinner parties. We weren’t prepared for this return to an unfamiliar era at all."


It's merely practice for the return to a localised medieval society. Coming soon (2050) to a country near you, courtesy of inadequate renewables and the gullible politicians who are ignorant about their dystopian dreamworld and so remain willing to sleepwalk society into a nightmare.

there is another alternative to your last line ,that they know fine well where we are headed, but see themselves as part of the chosen group that will have access to power that the plebs won't. i find it hard to ascribe incompetence over deliberate acts on such a major issue .

[turbobloke]

wc98 said:

there is another alternative to your last line ,that they know fine well where we are headed, but see themselves as part of the chosen group that will have access to power that the plebs won't. i find it hard to ascribe incompetence over deliberate acts on such a major issue .

Also, there may well be malign influences in play, from people like this one-time UN fruitloop.

Maurice Strong of the UN as Head of the 1992 Earth Summit in Rio de Janeiro said:

Isn't the only hope for the planet that the industrialized civilizations collapse? Isn't it our responsibility to bring that about?

[Gary C]

hidetheelephants said:

Gary C said:

Do you mean fusion ! If so

Cause we can't make it work "

If you mean fission, then, people don't like it, it is expensive, and it takes years to build anything.

A nuclear power station has become such a emotive thing. We can't pretend anymore that it's perfectly safe.

By any objective measure nuclear power is about the safest means of generating electricity available.

Gary C said:

They are very expensive to build and maintain.

How expensive is expensive? The overnight costs are pretty good.

Gary C said:

Small modular reactors may be the answer but maybe a terrorists dream having lots of little ones dotted around the country, where standards slip and regulators become massively stretched trying to keep on top of them all.

Also, security of fuel supplies and costs, now if we went fast breeder, we have enough depleted uranium to last years, but they cost a fortune in backend costs reprocessing the fuel to extract the plutonium.

There's reasonable evidence uranium can be extracted from seawater, so security of supply worries don't mean much even if Australia decided the UK is no longer a suitable customer. The high costs of reprocessing are mostly as a result of solid fuel handling/processing; liquid salt fuel eliminates most of those expensive processes.

Gary C said:

Thorium reactors are interesting, but we need to spend a LOT of money researching an designing and companies are not interested in spending, needs a government to do that.

What's a lot? Collectively there's been over £100bn invested in plant erected in the UK that's good for perhaps 4GW of non-despatchable power, that's a lot.

Even conservative estimates put a FOAK commercial scale MSR as less expensive than EPR on a £ per watt basis; the more adventurous/risky concepts may be far cheaper, the private ventures willing to offer an estimate price a first reactor at $0.5-1bn. It's impossible to quantify costs further without some considerable effort and expense in research, fortunately the chinese aren't fussy about such things and are spending perhaps $100m a year on finding out. Commerce has never been interested in developing nuclear power, only being paid to build it, as the payback period is far too long.

Gary C said:

Just wish we would stop burning all that gas just to make electricity.

Oh well, time to go to sleep, on nights in charge of a nuclear power station tonight

Its expensive - Capital investment of 100Bn puts a lot of investors off. My company is one of the few prepared to do so, and thats because its heavily embedded in the companies ethos. Not sure what you mean by 'overnight' costs.

Maintenance is expensive - a shutdown costs about 20-30m plus lost generation of ~40-60 days in the order of 80m plus running maintenance costs plus fuel costs plus wast costs plus saving for decommissioning. They are capital intensive and require companies that can think in the order of 30 years investment which is almost unheard of these days.

New reactor designs (as in really new, rather than designs like the EPR which are a development of the PWR) will cost. They always have. The AGR's fleet design costs were largely borne by the Government and not accounted in the build cost.

This puts investors off.

Any reprocessing of spent fuel is expensive, liquid salt is one of the worst materials to handle, especially when highly radioactive.

In the early days, we tried to tell the public that Nuclear was safe, perfectly safe (It was Terry Pratchet's first job !). Winscale, Chenobyl, Toki Muria, Fukushima, have demonstrated its not perfectly safe and trust in the public mind is hard to win back.

Finally, we are pouring real concrete on the site and it really looks as it its going to be built, but the final investment decision was a close run vote. Will Sizewell C get built ?

The fact that the Chinese are leading the research into new reactors really proves my point.

Not disagreeing with your view that nuclear is part of the future, just why its taking so long. I remember the original Hinckley Point C enquiry and the lorry's needed to cart the evidence about and it still didnt happen. To replace all the large coal/gas stations with nuclear would require a huge change in government and public thinking.

[Gary C]

Paddy_N_Murphy said:

But hey, they average PH'er knows better.

But then again, some of us have worked in the industry for 32 years and counting.



The other thing that puts people off is liabilities.

[Ali G]

Gary C said:

Its expensive - Capital investment of 100Bn puts a lot of investors off.

Costs tend to become less by building more - learning curve, experience and efficiency savings

Gary C said:

Maintenance is expensive - a shutdown costs about 20-30m plus lost generation of ~40-60 days in the order of 80m plus running maintenance costs plus fuel costs plus wast costs plus saving for decommissioning. They are capital intensive and require companies that can think in the order of 30 years investment which is almost unheard of these days.

Currently, the only viable 24/365 technology available - given UK Gov Paris Climate Change commitments. Cost is irrelevant under such conditions

Gary C said:

New reactor designs (as in really new, rather than designs like the EPR which are a development of the PWR) will cost. They always have. The AGR's fleet design costs were largely borne by the Government and not accounted in the build cost.

This puts investors off.

Reactor designs may be antiquated - QED

Gary C said:

Any reprocessing of spent fuel is expensive, liquid salt is one of the worst materials to handle, especially when highly radioactive.

In the early days, we tried to tell the public that Nuclear was safe, perfectly safe (It was Terry Pratchet's first job !). Winscale, Chenobyl, Toki Muria, Fukushima, have demonstrated its not perfectly safe and trust in the public mind is hard to win back.

In the days of steam power - boilers used to blow up with varying degrees of regularity resulting in not inconsiderable amounts of death and mutilation until standards in metallurgy and build were enforced.

Life itself is inherently unsafe - no-one gets out alive! Cars crash etc.

Gary C said:

Finally, we are pouring real concrete on the site and it really looks as it its going to be built, but the final investment decision was a close run vote. Will Sizewell C get built ?

The fact that the Chinese are leading the research into new reactors really proves my point.

Not disagreeing with your view that nuclear is part of the future, just why its taking so long. I remember the original Hinckley Point C enquiry and the lorry's needed to cart the evidence about and it still didnt happen. To replace all the large coal/gas stations with nuclear would require a huge change in government and public thinking.

Party politics may tend to concentrate more resources in swinging marginal voters than in communicating with the majority - its a consequence of that democracy thing!

[NJH]

There was a pit accident around the time of the Windscale fire, people conveniently forget all those who lost their lives cutting the black stuff out of holes miles under the ground. Many would like to go back to it tomorrow if they could but the public are still largely scared and mistrustful of nuclear power.

There is a common theme of course and its government, we have a real problem trusting anything done by a government department. I was another one of those people like many of you guys to have worked in this industry. Looking back to my time up north we all had a dim opinion of our own organisation, who would have believed that 20 years later after working across all parts of the UK private Defence engineering industry, that that period was technically, pretty much the high point for me.

[NJH]

On the liquid salt reactor, there are two very different kinds, there are the high temp molten salt concepts:
https://www.ornl.gov/msr

... and there are really old school table top reactors from the days back around the birth of nuclear research where Uranium sulfate was dissolved in water. I don't think we are talking about those.

I can remember as well when this thing was supposed to be the next big thing:
http://fhr.nuc.berkeley.edu

...bringing back the memories again, thanks guys.

[Ali G]

Fast breeder reactor tech from the late '60s

Dounreay

UK Gov said:

PFR had the dual role of providing power to the national grid and offering unique research and development facilities. PFR provided information for future design and operation of large commercial fast reactor stations. It was the final step towards bringing fast reactors into use as conventional power stations.

The United Kingdom decided in the late 1980s that there was no immediate need to take the next step to a conventional station and discontinued the programme.

More need required now, and with a degree of haste to meet commitments made under Paris Agreement!

[V8 Fettler]

Paddy_N_Murphy said:

V8 Fettler said:

In the absence of any meaningful data from you, we'll use the 5% minimum utilisation ratio.

With a broadbrush...... blah blah

Jog on.

Data is available - go find it.
If you can't find it - don't make it up and claim "we'll use".

My broadbrush is derived from http://media.nationalgrid.com/media/1304/fes-2016-...

and




Where's your data?