A very windy week at the end of December provides clear evidence of renewable generation being constrained. What implications does that have for the 'plan'?
I'm beginning to believe that a lot of this net-zero stuff is simply political posturing. So that our dear leaders can stand up in front of the world's media and claim they've installed 100% renewables. The fact that, as you have shown, most of this 100% is never used is something that's easy to characterise as a trifling detail that needn't concern the voters.
How many AAs would we need for 16TWh?
Assuming a 1.5V AA battery discharging at 100mA can yield 2Ah we have a capacity of 3Wh per battery.
16TWh = 16 * 10^6 * 10^6Wh requires ~5 trillion AAs. That's a lot of silenced drumming bunnies.
This equates to 125 million tonnes (25 grams each) or 1250 aircraft carriers.
Not trivial for a small island and I hope my arithmetic is correct!
Getting real data on constraints is difficult. You can get an approximation by looking at the wind forecast vs outturn reports - any big change downwards from a high forecast to a lower actual almost certainly represents curtailment, though it is hard to be precise about how much (and that must be a real problem anyway - you can't estimate what wasn't produced with certainty).
A more nitty gritty approach is to look at output wind farm by wind farm, but that is painful in terms of accessing and downloading the data. However, it can be very revealing about what drives curtailments between one wind farm and another. There are various categories of wind farms contractually.
The simplest are those which are just paid market price for their output. These are wind farms that have no Renewables Obligation support, and either have yet to qualify for CFD support because they are not fully commissioned, or have not taken up their CFDs in the present strong market conditions that offer a much better return than their lowball CFD strike price (Triton Knoll, Moray East, Hornsea 2). These will have every incentive to curtail on the economics any time market prices are negative: they can simply buy back any forward sale of output at a negative price and bank the profit, rather than simply accepting the forward sale price at a lower margin. All they stand to lose are REGOs, although those have recently started to become of material value rather than being worth just a few pence per MWh.
Next are wind farms paid Renewables Obligations for every MWh they generate. In order to curtail they need to be compensated for the loss of any ROs they would earn. Different wind farms are entitled to different levels of ROs, so it will be the ones that are on the lowest RO band that are cheapest to curtail, and will be first in the pecking order where a constraint is operationally required because there is insufficient transmission capacity somewhere on the system (the constraint need not be in the immediate vicininty, but might be - more likely it will be the chokepoint of the Scotland-England transmission flows). Meanwhile the more expensive wind farms get to keep on producing. The market price tends to be set by the size of subsidies at risk (RO+REGO), and will be negative, and the curtailment payment will be of similar magnitude.
Wind farms on CFDs get paid their full strike price in compensation when market prices are negative, Their net proceeds are the strike price reduced by the negative market price, which will in most cases still leave them with a handsome income and thus no incentive to curtail. The first exception to this is that should day ahead intermittent market reference prices be negative for six or more contiguous hours no compensation is paid for the duration, and they have full market exposure to negative prices, and thus an incentive to curtail. Future rounds of CFDs will see the six hour minimum dropped, with any hour with negative prices offering no protection - potentially a big income hit compared with earning the strike price on more or less 100% capacity production on a windy day.
The other exception is when National Grid decides to persuade a CFD wind farm to curtail for operational or other reasons. It appears this has been happening with Beatrice quite regularly, despite the fact that it would be entitled to its full strike price - currently £175.47/MWh - if it carried on producing to offset any negative market price. I have yet to track down its compensation payments, but I plan to be asking questions as to why consumers have been paying out very large compensation when much cheaper compensation for RO generators on 1 or 2 ROCs/MWh ought to be available. The Beatrice accounts suggest the compensation has been more than generous. Perhaps they are being asked to free capacity so that National Grid can reduce its liabilities for failure to connect other wind farms at all.
Is it possible to produce truly ‘green’ hydrogen and store it securely?"
So what would we do with that hydrogen taken from storage in our 'all-electric' paradise?
Those who blithely respond "generate electricity with it" would be unaware of reality regarding our existing CCGT & OCGT plants.
Section 3.7.1.9 Gas turbines on page 32 of HSE's "Injecting hydrogen into the gas network – a literature search" informs:
"A particular concern regarding ignition is the presence of hydrogen; since this gas ignites easily, there is concern that even small quantities of hydrogen in natural gas would be catastrophic for turbine behaviour. To illustrate this apprehension one major turbine manufacturer allows only traces of hydrogen in the fuel gas, while another manufacturer allows only 8.5% of hydrogen"
"Some context to those numbers: Dinorwyg stores up to 9,200 MWh and took over a decade to build. In total across the UK we have about 23,700 MWh of pumped storage in 4 schemes."
Chris, the late Prof Sir David MacKay listed our 4x pumped hydro schemes' total capaciity as 26.7GWh.
"There’s only one problem: we don’t have anything near the amount of <B><I>energy</i></b> storage needed..... Sure, there are pumped storage schemes like Dinorwyg in Wales and Nant de Drance in Switzerland which could theoretically store energy for weeks or even across seasons."
Electricity, rather than energy.
Dinorwig stores 9.1GWh and can discharge at 1.8GW
Nant de Drance stores 20GWh and can discharge at 0.9GW
For comparison, Britain has ~40,000 GWh of natural gas underground + LNG storage.
The recently re-opened Rough field now stores 9,350GWh (at a lower pressure than originally), and it alone can discharge at 63.25GW
What are your thoughts on schemes such as the Norway link, where in theory during windy times the power goes to Norway and allows them to refill their hydro reservoirs. And then when it’s calm we buy their hydro power. It sounds like it is effectively wind storage. I think the current connection does 1.5GW. So assuming 50:50 storage vs usage that could be up to 6TWhr of storage?
I've yet to see anyone show that anyone's solved the hydrogen embrittlement problem. Hydrogen leaks out of steel pipelines and embrittles the steel in the process. Hydrogen also has a surprisingly low energy density, as well. It sounds great until you start digging into the entire lifecycle.
I'm beginning to believe that a lot of this net-zero stuff is simply political posturing. So that our dear leaders can stand up in front of the world's media and claim they've installed 100% renewables. The fact that, as you have shown, most of this 100% is never used is something that's easy to characterise as a trifling detail that needn't concern the voters.
How many AAs would we need for 16TWh?
Assuming a 1.5V AA battery discharging at 100mA can yield 2Ah we have a capacity of 3Wh per battery.
16TWh = 16 * 10^6 * 10^6Wh requires ~5 trillion AAs. That's a lot of silenced drumming bunnies.
This equates to 125 million tonnes (25 grams each) or 1250 aircraft carriers.
Not trivial for a small island and I hope my arithmetic is correct!
BTW I tend to agree about peer-review!
Getting real data on constraints is difficult. You can get an approximation by looking at the wind forecast vs outturn reports - any big change downwards from a high forecast to a lower actual almost certainly represents curtailment, though it is hard to be precise about how much (and that must be a real problem anyway - you can't estimate what wasn't produced with certainty).
https://www.bmreports.com/bmrs/?q=foregeneration/dayaheadwindnsolar
A more nitty gritty approach is to look at output wind farm by wind farm, but that is painful in terms of accessing and downloading the data. However, it can be very revealing about what drives curtailments between one wind farm and another. There are various categories of wind farms contractually.
The simplest are those which are just paid market price for their output. These are wind farms that have no Renewables Obligation support, and either have yet to qualify for CFD support because they are not fully commissioned, or have not taken up their CFDs in the present strong market conditions that offer a much better return than their lowball CFD strike price (Triton Knoll, Moray East, Hornsea 2). These will have every incentive to curtail on the economics any time market prices are negative: they can simply buy back any forward sale of output at a negative price and bank the profit, rather than simply accepting the forward sale price at a lower margin. All they stand to lose are REGOs, although those have recently started to become of material value rather than being worth just a few pence per MWh.
Next are wind farms paid Renewables Obligations for every MWh they generate. In order to curtail they need to be compensated for the loss of any ROs they would earn. Different wind farms are entitled to different levels of ROs, so it will be the ones that are on the lowest RO band that are cheapest to curtail, and will be first in the pecking order where a constraint is operationally required because there is insufficient transmission capacity somewhere on the system (the constraint need not be in the immediate vicininty, but might be - more likely it will be the chokepoint of the Scotland-England transmission flows). Meanwhile the more expensive wind farms get to keep on producing. The market price tends to be set by the size of subsidies at risk (RO+REGO), and will be negative, and the curtailment payment will be of similar magnitude.
Wind farms on CFDs get paid their full strike price in compensation when market prices are negative, Their net proceeds are the strike price reduced by the negative market price, which will in most cases still leave them with a handsome income and thus no incentive to curtail. The first exception to this is that should day ahead intermittent market reference prices be negative for six or more contiguous hours no compensation is paid for the duration, and they have full market exposure to negative prices, and thus an incentive to curtail. Future rounds of CFDs will see the six hour minimum dropped, with any hour with negative prices offering no protection - potentially a big income hit compared with earning the strike price on more or less 100% capacity production on a windy day.
The other exception is when National Grid decides to persuade a CFD wind farm to curtail for operational or other reasons. It appears this has been happening with Beatrice quite regularly, despite the fact that it would be entitled to its full strike price - currently £175.47/MWh - if it carried on producing to offset any negative market price. I have yet to track down its compensation payments, but I plan to be asking questions as to why consumers have been paying out very large compensation when much cheaper compensation for RO generators on 1 or 2 ROCs/MWh ought to be available. The Beatrice accounts suggest the compensation has been more than generous. Perhaps they are being asked to free capacity so that National Grid can reduce its liabilities for failure to connect other wind farms at all.
"Hydrogen for Energy Storage?
Is it possible to produce truly ‘green’ hydrogen and store it securely?"
So what would we do with that hydrogen taken from storage in our 'all-electric' paradise?
Those who blithely respond "generate electricity with it" would be unaware of reality regarding our existing CCGT & OCGT plants.
Section 3.7.1.9 Gas turbines on page 32 of HSE's "Injecting hydrogen into the gas network – a literature search" informs:
"A particular concern regarding ignition is the presence of hydrogen; since this gas ignites easily, there is concern that even small quantities of hydrogen in natural gas would be catastrophic for turbine behaviour. To illustrate this apprehension one major turbine manufacturer allows only traces of hydrogen in the fuel gas, while another manufacturer allows only 8.5% of hydrogen"
"Some context to those numbers: Dinorwyg stores up to 9,200 MWh and took over a decade to build. In total across the UK we have about 23,700 MWh of pumped storage in 4 schemes."
Chris, the late Prof Sir David MacKay listed our 4x pumped hydro schemes' total capaciity as 26.7GWh.
https://www.withouthotair.com/c26/page_191.shtml
The Coire Glas project - 1.5GW / 30GWh - is due for completion due late 2029 / early 2030
https://www.inverness-courier.co.uk/news/coire-glas-pumped-hydro-scheme-gets-approval-from-scottish-government-215721/
"There’s only one problem: we don’t have anything near the amount of <B><I>energy</i></b> storage needed..... Sure, there are pumped storage schemes like Dinorwyg in Wales and Nant de Drance in Switzerland which could theoretically store energy for weeks or even across seasons."
Electricity, rather than energy.
Dinorwig stores 9.1GWh and can discharge at 1.8GW
Nant de Drance stores 20GWh and can discharge at 0.9GW
For comparison, Britain has ~40,000 GWh of natural gas underground + LNG storage.
The recently re-opened Rough field now stores 9,350GWh (at a lower pressure than originally), and it alone can discharge at 63.25GW
https://mip-prd-web.azurewebsites.net/DailySummaryReport
What are your thoughts on schemes such as the Norway link, where in theory during windy times the power goes to Norway and allows them to refill their hydro reservoirs. And then when it’s calm we buy their hydro power. It sounds like it is effectively wind storage. I think the current connection does 1.5GW. So assuming 50:50 storage vs usage that could be up to 6TWhr of storage?
I've yet to see anyone show that anyone's solved the hydrogen embrittlement problem. Hydrogen leaks out of steel pipelines and embrittles the steel in the process. Hydrogen also has a surprisingly low energy density, as well. It sounds great until you start digging into the entire lifecycle.