The Future of Power Generation in Great Britain

[turbobloke]

rscott said:

V8 Fettler said:

turbobloke said:

Without thinking long and hard, what would that picture look like in a world where our well-informed, wise and selfless politicians have shut down coal stations and are well on the way to the lunacy of decarbonisation?

Rhetorical question.

At the moment the situation mimicks playtime with some naughty games and it's not serious...yet.

I've modelled this very scenario for the UK, but the big unknown is: how low can wind go?

If we have no meaningful mass energy storage then 10TW of installed wind plus Hinkley C / hydro / solar would probably see us through on most days. The issue arises on a day such as today where it is possible that the parasitic load generated by 10TW of large wind turbines in low wind conditions could create a grid with a negative output.

20GW of installed wind produced this earlier:




If it was a dog, you'd have it put down.

What no pictures today?

Could that be because wind is currently suppyling more than coal and nuclear combined?

If so, that's unreliables and intermittency for you.

You'll be aware also that this ^ latest situation you describe is via policy not so much ability. Politicians are closing fossil fuel stations while they've been paying through the nose with our money to push e.g. windymills. There's no need for unreliables at all with sufficient coal, gas and nukes. The notion for not using them has no basis outside ideology..

[PRTVR]

rscott said:

What no pictures today?

Could that be because wind is currently suppyling more than coal and nuclear combined?

The problem is when it's not, you have to have nearly 100% back up from a real power station,
Who pays for the power station to be built and sit there till it's required? This makes for more expensive electricity.

[V8 Fettler]

rscott said:

V8 Fettler said:

turbobloke said:

Without thinking long and hard, what would that picture look like in a world where our well-informed, wise and selfless politicians have shut down coal stations and are well on the way to the lunacy of decarbonisation?

Rhetorical question.

At the moment the situation mimicks playtime with some naughty games and it's not serious...yet.

I've modelled this very scenario for the UK, but the big unknown is: how low can wind go?

If we have no meaningful mass energy storage then 10TW of installed wind plus Hinkley C / hydro / solar would probably see us through on most days. The issue arises on a day such as today where it is possible that the parasitic load generated by 10TW of large wind turbines in low wind conditions could create a grid with a negative output.

20GW of installed wind produced this earlier:




If it was a dog, you'd have it put down.

What no pictures today?

Could that be because wind is currently suppyling more than coal and nuclear combined?

The key risk is grid collapse. 10,000 hours of excess availability of generation is irrelevant when compared to one hour of insufficient generation leading to grid collapse.

[Condi]

alangla said:

OK.. Another stupid question time.
I'm not questioning the figures posted upthread at all, they all seem to match Gridwatch/Elexon.
Looking at spot prices - https://www.bmreports.com/bmrs/?q=balancing/system... - it looks like the price peaked today at around 11:30 (period 23)at £195/MW. This fits largely with the large coal generation figures posted upthread, in fact the price was over £100 from about 07:30 to 13:30. The bit I don't get is that now, at 16:00 (16:30 prices not posted yet), with darkness falling etc, the price seems to be down to about £50 (was £30 at 15:30), with a surplus (if I'm reading the negative figure in the NIV column correctly) in the system. Coal energy is also well down at 5.3GW with CCGT off the scale at 26.4GW How come?
Demand is about 46GW & usually the daily peak is about 17:00 at this time of year. Are the coal providers only interested in £100+ prices and the gas generators already contracted to provide for the afternoon peak?

Not a stupid question, but the Elexon website is only half the story.

The Elexon site just shows the imbalance pricing - IE what NG are having to pay to balance the system in real time. Wholesale prices will have been set in traded markets ahead of time. Markets ahead of time are all based on forecasts of supply and demand, but the system often dispatches long or short, and so NG need to take action to balance it. So what you're seeing is that overnight and into the afternoon the system had dispatched short, and NG were having to buy additional power to balance it, setting the cashout price (imbalance price) at £195/mwh, and then later on the system had dispatched long and NG were turning down plant and cashout was set at £50/mwh. Some more power stations must have been switched on by power companies for the evening to cover the demand peak.

Dont confuse the cashout value with the wholesale price for power - the cashout can be set by a system which is 1mw long or short, but suppliers and users will have bought their power in advance, and generators will have planned their station running usually the day before, although plant can also be turned on/off up/down on the day as well. Not many people will have actually paid £195/mwh for their power in that period - I would guess the wholesale price ahead of time would have been £65-70.

Its very rare (almost impossible) that anyone is actually fully balanced at any given moment, but overall the system has to be balanced, and so NG are constantly turning stations up and down (or switching them on and off), to do so.

jet_noise said:

Is there some regulation requiring distributors(? or other part of the network) to preferentially take wind/solar over fossil fueled supply?

No, but there is a requirement for NG to balance the system as cost efficiently as possible. Wind power is only taken off the system generally as a last resort because it is considerably more expensive for NG (and the customer) than turning down a thermal station, due to loss of subsidy when its not generating. (No generation = no subsidy). It is almost always done for system constraints rather than balancing for energy.

Edited by Condi on Sunday 27th January 09:56

[Talksteer]

PRTVR said:

rscott said:

What no pictures today?

Could that be because wind is currently suppyling more than coal and nuclear combined?

The problem is when it's not, you have to have nearly 100% back up from a real power station,
Who pays for the power station to be built and sit there till it's required? This makes for more expensive electricity.

The government accepted the findings of Dieter Helm's review into power generation.

One of the reforms will be that all suppliers will have to deliver dependable power which means that renewables will need to have a contract with batteries or peakers. Thus intermittent suppliers will pay the grid cost of their intermittency.

Carbon will also be priced in so coal isn't coming back. But nuclear should do pretty well out of such a regime especially if the regulated asset base model is used.

[PRTVR]

Talksteer said:

PRTVR said:

rscott said:

What no pictures today?

Could that be because wind is currently suppyling more than coal and nuclear combined?

The problem is when it's not, you have to have nearly 100% back up from a real power station,
Who pays for the power station to be built and sit there till it's required? This makes for more expensive electricity.

The government accepted the findings of Dieter Helm's review into power generation.

One of the reforms will be that all suppliers will have to deliver dependable power which means that renewables will need to have a contract with batteries or peakers. Thus intermittent suppliers will pay the grid cost of their intermittency.

Carbon will also be priced in so coal isn't coming back. But nuclear should do pretty well out of such a regime especially if the regulated asset base model is used.

But no one is prepared to pay for nuclear, so we are left with wind and gas, not a good position to be in if we have a problem with gas the grid goes down.
How do we compete with countries that use cheep coal power stations, china for example?
It's easy to focus on the production side but it ignores the price to the end user.

[jet_noise]

Condi said:

jet_noise said:

Is there some regulation requiring distributors(? or other part of the network) to preferentially take wind/solar over fossil fueled supply?

No, but there is a requirement for NG to balance the system as cost efficiently as possible. Wind power is only taken off the system generally as a last resort because it is considerably more expensive for NG (and the customer) than turning down a thermal station, due to loss of subsidy when its not generating. (No generation = no subsidy). It is almost always done for system constraints rather than balancing for energy.

Edited by Condi on Sunday 27th January 09:56

Thanks, Condi.

NG= National Grid?
Is above wind cost minus subsidy less than thermal cost?

[Condi]

jet_noise said:

Thanks, Condi.

NG= National Grid?
Is above wind cost minus subsidy less than thermal cost?

NG = National Grid.

Thermal will generally pay NG to turn their stations down. If it costs £60 to generate 1mw, then its cost efficient to offer to pay NG £50 per mw and not generate (IE £10 profit). Some stations will offer to pay more, others will pay less.

Wind gets paid subsidy per mw of generation, and so if they are turned down they lose the subsidy, which can be anything up to £160 per mw for offshore wind. So they demand that £160/mw from NG if they have to be turned down.

Hence why generally thermal is turned up and down for balancing, but wind is only turned up and down for system reasons.

[jet_noise]

Condi said:

NG = National Grid.

Thermal will generally pay NG to turn their stations down. If it costs £60 to generate 1mw, then its cost efficient to offer to pay NG £50 per mw and not generate (IE £10 profit). Some stations will offer to pay more, others will pay less.

Wind gets paid subsidy per mw of generation, and so if they are turned down they lose the subsidy, which can be anything up to £160 per mw for offshore wind. So they demand that £160/mw from NG if they have to be turned down.

Hence why generally thermal is turned up and down for balancing, but wind is only turned up and down for system reasons.

If I'm getting this right then:
NG has to pay a generator even when it's not being used.
It costs almost 3x as much for offshore wind as thermal.
And power is 4x more expensive (than thermal on its own) when there is excess such that one or the other is turned down.

Do those figures include capital costs or are they on top?

[rolando]

On the matter of storage:
Misconceptions about battery storage

[WatchfulEye]

jet_noise said:

If I'm getting this right then:
NG has to pay a generator even when it's not being used.
It costs almost 3x as much for offshore wind as thermal.
And power is 4x more expensive (than thermal on its own) when there is excess such that one or the other is turned down.

Do those figures include capital costs or are they on top?

Energy consumers (or suppliers) will make a forecast of energy demand in advance. They will use that forecast to pre-order electricity from generators.

Sometimes these forecasts are wrong. Let's say consumers have over ordered. The power generators have a contract to deliver, and they are expecting to get paid. However, the customer doesn't want to pay for energy they no longer want or can no longer use.

In this scenario where the forecasts are wrong and the grid is "imbalanced", national grid intervene. They will ask individual generators to under-deliver on their contracts. Not too unsurprisingly, if a generator is being asked not to sell their product which they had planned in advance to sell, they may want some financial compensation.

There is a balancing market - generators submit their prices for "balancing services" (short notice reduction or increase in power output). In the event of an imbalance, national grid will purchase the appropriate amount of "balancing services" from the market, starting with the lowest priced bids.

For something like a wind turbine, there is little scope to increase output on demand at short notice, so a bid for a short notice increase cannot be submitted. As there are no significant marginal costs (such as fuel), then the operator would typically bid their full contracted sale price for reduction (e.g. £160/MWh).

For something like a gas turbine, then provided that the operator has not committed the full output of the plant, they can submit a bid to increase power, at any price above their fuel costs. Similarly, they can also submit a bid to reduce power - let's say they've contracted to sell power at £40/MWh, but their fuel and carbon tax cost is £30/MWh, giving £10/MWh profit. They might be happy to bid £10/MWh for a short term power reduction, as they only want to replace their profit, and don't need to replace their fuel costs.

[jet_noise]

WatchfulEye said:

jet_noise said:

If I'm getting this right then:
NG has to pay a generator even when it's not being used.
It costs almost 3x as much for offshore wind as thermal.
And power is 4x more expensive (than thermal on its own) when there is excess such that one or the other is turned down.

Do those figures include capital costs or are they on top?

Energy consumers (or suppliers) will make a forecast of energy demand in advance. They will use that forecast to pre-order electricity from generators.

Sometimes these forecasts are wrong. Let's say consumers have over ordered. The power generators have a contract to deliver, and they are expecting to get paid. However, the customer doesn't want to pay for energy they no longer want or can no longer use.

In this scenario where the forecasts are wrong and the grid is "imbalanced", national grid intervene. They will ask individual generators to under-deliver on their contracts. Not too unsurprisingly, if a generator is being asked not to sell their product which they had planned in advance to sell, they may want some financial compensation.

There is a balancing market - generators submit their prices for "balancing services" (short notice reduction or increase in power output). In the event of an imbalance, national grid will purchase the appropriate amount of "balancing services" from the market, starting with the lowest priced bids.

For something like a wind turbine, there is little scope to increase output on demand at short notice, so a bid for a short notice increase cannot be submitted. As there are no significant marginal costs (such as fuel), then the operator would typically bid their full contracted sale price for reduction (e.g. £160/MWh).

For something like a gas turbine, then provided that the operator has not committed the full output of the plant, they can submit a bid to increase power, at any price above their fuel costs. Similarly, they can also submit a bid to reduce power - let's say they've contracted to sell power at £40/MWh, but their fuel and carbon tax cost is £30/MWh, giving £10/MWh profit. They might be happy to bid £10/MWh for a short term power reduction, as they only want to replace their profit, and don't need to replace their fuel costs.

Thanks W E.

The usage case (as it's called in my industry) condi is illustrating is solely when the forecast is wrong.
Is there any data to say how often that is?
I understand that usage may be largely predictable but renewable generation (especially wind, day/night and season being obvious general indicators for solar!) does what it does at the weather's whim.
Is some average value used for renewables as an input into these forecasts?

[Evanivitch]

rolando said:

On the matter of storage:
Misconceptions about battery storage

I tend to agree, and it's a point I've discussed repeatedly with people that have celebrated the apparent failure of wylfa newydd.

Batteries can play a role in energy, certainly on a domestic scale for many, but they're not the answer the renewables variation.

[Jambo85]

Condi said:

NG = National Grid.

Thermal will generally pay NG to turn their stations down. If it costs £60 to generate 1mw, then its cost efficient to offer to pay NG £50 per mw and not generate (IE £10 profit). Some stations will offer to pay more, others will pay less.

Wind gets paid subsidy per mw of generation, and so if they are turned down they lose the subsidy, which can be anything up to £160 per mw for offshore wind. So they demand that £160/mw from NG if they have to be turned down.

Hence why generally thermal is turned up and down for balancing, but wind is only turned up and down for system reasons.

Well explained Condi, thanks.

You've got me wondering about the other possibility for balancing - storage. Pumped hydro was the one which came to mind but batteries will be the same if/when we have them in any significant capacity. Who makes the call that a pumped hydro station will soak up the excess capacity in the grid and pump a load of water to the top of a hill? Is it some back and forth between the operator and NG bartering over how cheaply they can have the energy to do it and whether it is worth their while, or can NG tell them they shall be doing it, or somewhere in between?

RE the storage article above about batteries, I'd be interested to know how many MWh of pumped hydro storage we have if anyone knows. I realise it isn't enough btw!

PS great thread - I've been watching it for a while and there are obviously plenty of people who know their stuff sharing what they know, largely informed debate, PH at its best. My qualification is in electrical engineering so I understand the concepts theoretically but never worked in the power sector, so practically and commercially I know nothing.

[alangla]

Jambo85 said:

RE the storage article above about batteries, I'd be interested to know how many MWh of pumped hydro storage we have if anyone knows. I realise it isn't enough btw!

PS great thread - I've been watching it for a while and there are obviously plenty of people who know their stuff sharing what they know, largely informed debate, PH at its best. My qualification is in electrical engineering so I understand the concepts theoretically but never worked in the power sector, so practically and commercially I know nothing.

+1 - thanks especially to Condi for answering my questions, I'm genuinely learning something here.

On the pumped storage question,
Dinorwig is apparently 9.1GWh - https://en.wikipedia.org/wiki/Dinorwig_Power_Stati...
Cruachan is 7.1 GWh - https://en.wikipedia.org/wiki/Cruachan_Power_Stati...
Foyers & Ffestiniog, not clear - https://en.wikipedia.org/wiki/Falls_of_Foyershttps://en.wikipedia.org/wiki/Ffestiniog_Power_Sta...http://sse.com/whatwedo/ourprojectsandassets/renew...

[Condi]

jet_noise said:

Thanks W E.

The usage case (as it's called in my industry) condi is illustrating is solely when the forecast is wrong.
Is there any data to say how often that is?
I understand that usage may be largely predictable but renewable generation (especially wind, day/night and season being obvious general indicators for solar!) does what it does at the weather's whim.
Is some average value used for renewables as an input into these forecasts?

Usage is not as largely predictable as you might think.
Then on top of that, renewable output is naturally variable, even with the best forecasts.
And finally, power stations have a habit of being temperamental. Its a very rare day everything works as expected.

Its a big, ongoing game. And remember, traders are deliberately over or under-buying their demand, turning their stations on/off, etc, all in relation to what they expect the cashout cost to be, and what they can buy or sell to someone else.

You can look on the Elexon website and see what volume of power is being bought and sold by NG to balance the network.

Jambo85 said:

Is it some back and forth between the operator and NG bartering over how cheaply they can have the energy to do it and whether it is worth their while, or can NG tell them they shall be doing it, or somewhere in between?

The company simply submits a price they want to do it for, and NG decide what is cheapest to do. In theory the company could ask for £100 to take the power, and it would still be cheaper than NG paying £150 to the wind turbine to turn off. In practice its better to make it attractive - if NG are going to give you free power to pump water up hill, the same power is then sold back to NG to balance the system the other way at £100. Easy £100 profit.

[WatchfulEye]

jet_noise said:

Thanks W E.

The usage case (as it's called in my industry) condi is illustrating is solely when the forecast is wrong.
Is there any data to say how often that is?
I understand that usage may be largely predictable but renewable generation (especially wind, day/night and season being obvious general indicators for solar!) does what it does at the weather's whim.
Is some average value used for renewables as an input into these forecasts?

The balancing mechanism is a complex thing, and the description above is an oversimplified example of just one facet of balancing. Balancing is needed whenever supply fails to match demand.

This could be because of incorrectly forecasting demand, incorrectly forecasting supply (e.g. variable generation, or unavailability/malfunction of plant), inability to deliver from site of supply to site of demand (e.g. power line failure, or powerlines at maximum capacity).

On top of that balancing services can be procured on different time scales. For example, "reserve" services are procured in advance, and represent a payment from national grid to plant operators to hold their plant in a condition in which they can guarantee availability of additional electricity at short notice - typically 2 minutes for "fast" reserve, or 15 minutes for "short term" operating reserve. An hourly availability fee is paid for each MW of capacity which is made available for reserve. "Response" services are also procured in advance, but represent standing orders to adjust supply/demand on a second-by-second basis in response to grid frequency. All generators have the capability of offering response, but there are technical differences in how it is delivered. Batteries are particularly effective at offering response, due to near instant operation, and the ability to offer "negative" response - by absorbing excess power.

For example, national grid recently procured 200 MW of battery response services at a cost of £7/MW/h for a period of 4 years - in other words, in response to this tender, the operator of a 50 MW battery (capable of discharging or charging at 50 MW with 1 second reposne, for a duration of up to 30 minutes) would receive a payment of £350 for each hour in which the battery is available to automatically respond to grid conditions. Energy for charging/discharge would be billed separately.

There are a variety of other balancing services, such as voltage regulation, "black start" services, and so on, but these are relatively minor costs.

The balancing market summaries are open information:
https://www.nationalgrideso.com/balancing-data/sys...

For example, you can see here that in Nov 2018, national grid spent £111 million on balancing services. Most of this was actually "constraints" - compensation to generators because national grid was unable to collect energy which the generator had already agreed to sell. This is mostly wind energy - wind electricity has a high value to the generator (because of subsidies), but on-shore wind generation is concentrated in rural areas where grid infrastructure is weak and large distances and sensitive environments would entail prohibitive upgrade costs.

[robinessex]

Wouldn't all this 'price for energy' bks go away if we renationalised the whole bloody lot?

[StanleyT]

WatchfulEye said:

Energy consumers (or suppliers) will make a forecast of energy demand in advance. They will use that forecast to pre-order electricity from generators.

Sometimes these forecasts are wrong. Let's say consumers have over ordered. The power generators have a contract to deliver, and they are expecting to get paid. However, the customer doesn't want to pay for energy they no longer want or can no longer use.

In this scenario where the forecasts are wrong and the grid is "imbalanced", national grid intervene. They will ask individual generators to under-deliver on their contracts. Not too unsurprisingly, if a generator is being asked not to sell their product which they had planned in advance to sell, they may want some financial compensation.

There is a balancing market - generators submit their prices for "balancing services" (short notice reduction or increase in power output). In the event of an imbalance, national grid will purchase the appropriate amount of "balancing services" from the market, starting with the lowest priced bids.

For something like a wind turbine, there is little scope to increase output on demand at short notice, so a bid for a short notice increase cannot be submitted. As there are no significant marginal costs (such as fuel), then the operator would typically bid their full contracted sale price for reduction (e.g. £160/MWh).

For something like a gas turbine, then provided that the operator has not committed the full output of the plant, they can submit a bid to increase power, at any price above their fuel costs. Similarly, they can also submit a bid to reduce power - let's say they've contracted to sell power at £40/MWh, but their fuel and carbon tax cost is £30/MWh, giving £10/MWh profit. They might be happy to bid £10/MWh for a short term power reduction, as they only want to replace their profit, and don't need to replace their fuel costs.

Is that what may be described as a BOLA - balance on load offer? I was on an Engineering Institute tour of a power plant when a "BOLA" came in. Basically the 20 of us of the tour were ignored for 20 minutes whilst additional turbines int he plant were brought on line. Hectic it seemed and this was a conventional plant. I guess this is why nuclear is baseload only, you don't want the operators turning nucs on and off and getting stressed?

[Jambo85]

alangla said:

On the pumped storage question,
Dinorwig is apparently 9.1GWh - https://en.wikipedia.org/wiki/Dinorwig_Power_Stati...
Cruachan is 7.1 GWh - https://en.wikipedia.org/wiki/Cruachan_Power_Stati...
Foyers & Ffestiniog, not clear - https://en.wikipedia.org/wiki/Falls_of_Foyershttps://en.wikipedia.org/wiki/Ffestiniog_Power_Sta...http://sse.com/whatwedo/ourprojectsandassets/renew...

Condi said:

The company simply submits a price they want to do it for, and NG decide what is cheapest to do. In theory the company could ask for £100 to take the power, and it would still be cheaper than NG paying £150 to the wind turbine to turn off. In practice its better to make it attractive - if NG are going to give you free power to pump water up hill, the same power is then sold back to NG to balance the system the other way at £100. Easy £100 profit.

Thank you both.

As an observation, the Gridwatch sites don't seem to show a negative generation when pumped hydro is pumping - I guess it is included in the demand curve.