"Solar PV is given the realistic load factor of 11 %". I can't seem to find out whether the 11% refers to a 12 hour or a 24 hour day! Should I assume that night time counts for Solar PV as well?
We've had a 2.5Kw domestic solar PV for the past 12 years or so. In that time it has generated on average 4.94kWh/day. This is 8% of capacity for a 24 hour day. We live in the unsunny south west of Scotland in what I presume is an average site.
Is 11% realistic or should it be even lower given practical experience?
However, the crucial figure is that for Januarys, our month of greatest electricity demand, solar in Britain generates at just 4% CF. And contributes NetZero to January's daily peak demands.
Seems to me that Net Zero and Energy Security are mutually exclusive, at least with the cretinous approach currently being pursued by most governments and political parties.
I think the approach, however you want to describe it, is currently driven by #GroupThink. The lack of any 'red team' counter-narrative from people with sufficient science / engineering know-how is palpable.
The really big fly in the ointment for wind and solar is curtailment. As more and more capacity is added, output soars on windy and sunny days. But once there is enough capacity to meet demand, adding more on these days just produces a useless surplus. Add more capacity, and the number of hours with surpluses increase, while the surpluses in already surplus hours grow bigger. All while doing very little to increase output on windless days. The number of useful hours from adding another wind farm drops, so it must earn its cost over fewer and fewer useful hours of output.
By the time we reach about 50GW of wind capacity against current demand the useful output is down to about half, so the real cost is double. Crank up to 90GW and the useful marginal output is under 20%, making that extra GW over 5 times as costly. On average, about half of all output is useless.
Cue storage. But storage is very costly, and it's inefficient, with large losses coverting surpluses for storage and converting them back again. Moreover, to earn its keep storage needs a margin between input cost and output realisation. The margin earned depends not only on the price difference, but also the throughput. Storage that turns over frequently needs a much smaller margin to be viable. When you are faced with the need for interseasonal storage, or worse storage across perhaps several years, the economics get shot to pieces, and storage losses increase. It's cheaper to curtail. But that isn't cheap, as we have already seen.
I agree with you about the true believers. I have almost given up trying to engage with people on this subject on platforms such as Linkedin due to the almost religious tone of their replies. In fact "engaging" is an exaggeration as most do simply not engage.
So we agree that, without some technological advance which at present has not happened and is not in sight, achievement of carbon zero is probably not possible.
However, I worry that in saying this we are giving the government a get out: "It's not possible, we'd be better off doing nothing." Which, I assume, explains the over-simple messages of the "true believers"
I also worry that by aiming blindly for zero carbon we may go down unproductive rabbit holes and end up not reducing GHG emissions or even possibly increasing them.
A better plan would be to do simulations based on scenarios which we think really are possible and base our strategy on that. At present, I am not aware of either those simulations or a strategy.
But somebody (apart from Tesla) must be doing something like this.
The last person who I'm aware of who used this kind of approach was David JC Mackay. I spoke to one of the presenters at a climate change meeting recently about his work and the response was a patronising "oh things have moved on a bit since then". However the person was not able to point me to an updated version of the same thing.
Mackay's (reluctant) conclusion was that it was not possible for the UK to rely only on renewables; wind, solar and tidal to generate electricity. I would be half way to believing if someone could show me a calculation, even at the back-of-an-envelope level of Mackay, that it was now possible.
Coal-based energy began in the UK centuries ago. I just found out from a Guardian article .../environment/gallery/2015/dec/18/coal-mining-britain-brief-history-in-pictures that "In 1575, the first coal mine was sunk under the Firth of Forth. By 1700, British coal output stood at about 3m tonnes, increasing to meet demand for fuel to power steam engines".
So coal then oil tech have had very looooong times to develop. Equally, investments into infrastructure and technology and everything has had plenty of time to be funded. And there have been many failures along the way- dry wells etc. the costs of which have been borne by private investors.
Now we have a state-sponsored "climate emergency" and governments picking 'winners' from the limited span of technologies available, funded by subsidies of various forms, all against looming 'legally-binding targets'.
(Except, parliament is sovereign in the UK, and no future parliament can be bound by a predecessor, i.e. laws can be repealed.)
Net Zero was easy to promise when the free money fountain was flowing. Now that's changed.
I suspect we'll get to the point in the UK of having some power outages, and then the uproar will drown out the "true believers" especially if there are deaths.
Meantime I expect money we can ill afford will continue to be spent on the 'winners' that were picked.
"To put it another way: the only way Solar PV and Wind can currently be accommodated by the GB power grid, is by having an equal capacity of controllable dispatchable fossil generation available at all times. Even California is waking up to this reality on their grid."
I think this is they key thing which I haven't seen mentioned in any other discussion. As far as I can see, to guarantee no blackouts, the UK will need to maintain a non-solar or wind generating capacity equal or close to 100% of the peak electricity demand.
The capacity will not be used for a significant amount of the time but it will need to be kept in working order, maintained continuously, and renewed at the end of its life. The fuel supply and fuel transport infrastructure for these facilities, the personnel to run them and the expertise to maintain them will also need to be sustained and guaranteed. The cost of this duplicate generating system will be high.
I really don't see an alternative to this. Providing sufficient storage does not look to me to be practical or even possible. Creating sufficient interconnection with other parts of the world which might have surplus seems to me to be pretty much in the realms of science fiction too. Guaranteeing that the storage or the source of the energy supplied by interconnection is "zero carbon" seems also in the realms of fantasy.
I suppose that a mix of all these; fossil fuel and nuclear generating capacity, storage and interconnection is the most likely scenario which will eventually evolve, however that will not be "zero carbon".
Thank you Andrew, and with current technology: exactly.
The HM Gov line seems to be a mixture of "the tech we'll need to make it all work will be developed shortly, don't worry" and "we'll use smart technology to manage demand" (also known as "the peasants will have their power turned off when supply fails to match demand").
Too many people appear to be "true believers" who, even *if* they read my posts, simply dismiss the data. They're too personally invested.
And I'm sure many people who work with or for "true believer companies / organisations" won't stick their heads above the parapet in case it damages their career.
"Solar PV is given the realistic load factor of 11 %". I can't seem to find out whether the 11% refers to a 12 hour or a 24 hour day! Should I assume that night time counts for Solar PV as well?
We've had a 2.5Kw domestic solar PV for the past 12 years or so. In that time it has generated on average 4.94kWh/day. This is 8% of capacity for a 24 hour day. We live in the unsunny south west of Scotland in what I presume is an average site.
Is 11% realistic or should it be even lower given practical experience?
Hi Jim
""Solar PV is given the realistic load factor of 11 %". I can't seem to find out whether the 11% refers to a 12 hour or a 24 hour day!"
That'd be over the entire year.
https://i.postimg.cc/5NF3PcBz/2021-Solar-generation-4-of-our-energy-mix-9-8-Capacity-Factor.jpg
However, the crucial figure is that for Januarys, our month of greatest electricity demand, solar in Britain generates at just 4% CF. And contributes NetZero to January's daily peak demands.
Thanks, Ron. So my figure of 8% is the compatible one. The supplier of my panels predicted 9.8% using various tables and magic incantations.
Your point about Januarys is well made. Perhaps we'll all have to learn to hibernate.
Hello Jim, Ron,
The load factor as calculated in DUKES 6.3 is based on 8760 hours per year, i.e. all day every day.
Your panel supplier presumably had access to this type of info:
https://www.photonenergy.co.uk/solar-map-of-the-uk
... together with local factors - shading, angle of your panels, etc.
Hibernation, I like it!
Seems to me that Net Zero and Energy Security are mutually exclusive, at least with the cretinous approach currently being pursued by most governments and political parties.
Thanks, Robin.
I think the approach, however you want to describe it, is currently driven by #GroupThink. The lack of any 'red team' counter-narrative from people with sufficient science / engineering know-how is palpable.
But, y'know, Everything is Awesome!
https://www.youtube.com/watch?v=9cQgQIMlwWw
The really big fly in the ointment for wind and solar is curtailment. As more and more capacity is added, output soars on windy and sunny days. But once there is enough capacity to meet demand, adding more on these days just produces a useless surplus. Add more capacity, and the number of hours with surpluses increase, while the surpluses in already surplus hours grow bigger. All while doing very little to increase output on windless days. The number of useful hours from adding another wind farm drops, so it must earn its cost over fewer and fewer useful hours of output.
By the time we reach about 50GW of wind capacity against current demand the useful output is down to about half, so the real cost is double. Crank up to 90GW and the useful marginal output is under 20%, making that extra GW over 5 times as costly. On average, about half of all output is useless.
Cue storage. But storage is very costly, and it's inefficient, with large losses coverting surpluses for storage and converting them back again. Moreover, to earn its keep storage needs a margin between input cost and output realisation. The margin earned depends not only on the price difference, but also the throughput. Storage that turns over frequently needs a much smaller margin to be viable. When you are faced with the need for interseasonal storage, or worse storage across perhaps several years, the economics get shot to pieces, and storage losses increase. It's cheaper to curtail. But that isn't cheap, as we have already seen.
I agree with you about the true believers. I have almost given up trying to engage with people on this subject on platforms such as Linkedin due to the almost religious tone of their replies. In fact "engaging" is an exaggeration as most do simply not engage.
So we agree that, without some technological advance which at present has not happened and is not in sight, achievement of carbon zero is probably not possible.
However, I worry that in saying this we are giving the government a get out: "It's not possible, we'd be better off doing nothing." Which, I assume, explains the over-simple messages of the "true believers"
I also worry that by aiming blindly for zero carbon we may go down unproductive rabbit holes and end up not reducing GHG emissions or even possibly increasing them.
A better plan would be to do simulations based on scenarios which we think really are possible and base our strategy on that. At present, I am not aware of either those simulations or a strategy.
But somebody (apart from Tesla) must be doing something like this.
The last person who I'm aware of who used this kind of approach was David JC Mackay. I spoke to one of the presenters at a climate change meeting recently about his work and the response was a patronising "oh things have moved on a bit since then". However the person was not able to point me to an updated version of the same thing.
Mackay's (reluctant) conclusion was that it was not possible for the UK to rely only on renewables; wind, solar and tidal to generate electricity. I would be half way to believing if someone could show me a calculation, even at the back-of-an-envelope level of Mackay, that it was now possible.
Hello again Andrew,
I try to take a long view.
Coal-based energy began in the UK centuries ago. I just found out from a Guardian article .../environment/gallery/2015/dec/18/coal-mining-britain-brief-history-in-pictures that "In 1575, the first coal mine was sunk under the Firth of Forth. By 1700, British coal output stood at about 3m tonnes, increasing to meet demand for fuel to power steam engines".
Drilling for oil seems to have begun in the 1850s, see for example ...thoughtco.com/edwin-drake-first-oil-well-1859-1773897
So coal then oil tech have had very looooong times to develop. Equally, investments into infrastructure and technology and everything has had plenty of time to be funded. And there have been many failures along the way- dry wells etc. the costs of which have been borne by private investors.
Now we have a state-sponsored "climate emergency" and governments picking 'winners' from the limited span of technologies available, funded by subsidies of various forms, all against looming 'legally-binding targets'.
(Except, parliament is sovereign in the UK, and no future parliament can be bound by a predecessor, i.e. laws can be repealed.)
Net Zero was easy to promise when the free money fountain was flowing. Now that's changed.
I suspect we'll get to the point in the UK of having some power outages, and then the uproar will drown out the "true believers" especially if there are deaths.
Meantime I expect money we can ill afford will continue to be spent on the 'winners' that were picked.
"To put it another way: the only way Solar PV and Wind can currently be accommodated by the GB power grid, is by having an equal capacity of controllable dispatchable fossil generation available at all times. Even California is waking up to this reality on their grid."
I think this is they key thing which I haven't seen mentioned in any other discussion. As far as I can see, to guarantee no blackouts, the UK will need to maintain a non-solar or wind generating capacity equal or close to 100% of the peak electricity demand.
The capacity will not be used for a significant amount of the time but it will need to be kept in working order, maintained continuously, and renewed at the end of its life. The fuel supply and fuel transport infrastructure for these facilities, the personnel to run them and the expertise to maintain them will also need to be sustained and guaranteed. The cost of this duplicate generating system will be high.
I really don't see an alternative to this. Providing sufficient storage does not look to me to be practical or even possible. Creating sufficient interconnection with other parts of the world which might have surplus seems to me to be pretty much in the realms of science fiction too. Guaranteeing that the storage or the source of the energy supplied by interconnection is "zero carbon" seems also in the realms of fantasy.
I suppose that a mix of all these; fossil fuel and nuclear generating capacity, storage and interconnection is the most likely scenario which will eventually evolve, however that will not be "zero carbon".
Thank you Andrew, and with current technology: exactly.
The HM Gov line seems to be a mixture of "the tech we'll need to make it all work will be developed shortly, don't worry" and "we'll use smart technology to manage demand" (also known as "the peasants will have their power turned off when supply fails to match demand").
Too many people appear to be "true believers" who, even *if* they read my posts, simply dismiss the data. They're too personally invested.
And I'm sure many people who work with or for "true believer companies / organisations" won't stick their heads above the parapet in case it damages their career.