Solar Power In Summer
By Paul Homewood
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We often tend to think that it is winter when electricity shortages are likely to occur. After all, in summer demand is lower and we have solar power as well.
With this in mind, let’s have a look at the last seven days, which have not been untypical from a weather point of view. Here is the generation mix:
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https://www.solar.sheffield.ac.uk/pvlive/#
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Don’t pay too much attention to the individual bands at the moment. Instead focus on the four bands in the chart below.
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As is often the case in summer, wind power frequently drops away close to zero. Solar power peaked at over 10 GW on some days, but on others it did not even reach 5 GW. Most important of all, of course, is gas which is always on hand, with up to 15 GW required at times, even with I/Cs running at full blast.
In total, gas provided 33%, and nuclear a further 17%. Wind and solar came to 11% and 9% respectively.
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Fast forward to 2035, when the Government hopes we’ll have 70 GW of solar power, compared to the current 16 GW.
In theory that should raise solar output from 410 GWh for the week to about 1800 GWh. However, demand is likely to rise as well, maybe from 4600 to 6000 GWh. In other words the increase in solar power will probably only be enough to cover the extra demand. Wind should add some extra output thanks to new wind farms, but not when the wind does not blow.
That means we will potentially need as much power from non-renewable sources as we do now at times during summer months.
But that’s just the tip of the iceberg.
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Whereas solar power can peak at 10 GW now at midday, this figure will rise to 44 GW when there is 70 GW of capacity. This will always exceed demand, and the surplus will be wasted unless it is exported to Europe, who will have their own surplus solar power. What we manage to export will inevitably be at prices well below CfD strike prices, and it will be billpayers/taxpayers who will end up footing the bill.
There is of course the option of battery storage, both to mop up these surpluses and to supply power at night.
So how much storage would we need, simply to balance solar output throughout each 24 hour period.
Let’s look at the period from noon on the 19th to noon on the 20th:
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https://www.solar.sheffield.ac.uk/pvlive/#
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The average hourly generation through the 24-hour period was 3289 MWh, so how much storage would we need to ensure that this amount of electricity could be fed to the grid every hour of the day and night, while mopping up the midday surplus?
The surplus begins to build up at noon, (remember that the graph starts at noon), and peaks at 27 GWh at around 5pm. By 2am the surplus is entirely used up, and the deficit accumulates to about 13 GWh at about 7.30am.
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I could of course started the graph at 7.30am, which would shown a bigger surplus and no deficit. However the results are exactly the same in terms of storage – that we would need about 40 GWh of battery storage – (27 GWh + 13 GWh).
This is of course just one day, and there will probably be other days when more would be needed. We also need to factor in energy loss during the charging and discharging of the battery. Also the fact that batteries would never be charged to 100%, nor discharged to zero.
But 40 GWh is a good ball park figure, and we can multiply that up to 175 GWh when we have 70 GW of solar power. Currently we have about 2.8 GWh of battery storage around the country, so plainly this does not even start to address the needs imposed by a mass rollout of solar farms.
Looked at another way, we currently have 16 GW of solar power. If solar farms were obliged to provide a steady supply to the grid, they would need to instal 40 GW of battery storage with 1-hour discharge, the typical battery specification. Effectively for every MW of solar capacity, they would have to build 3 MW of storage.
And thjs is just to balance out daily generation, it does nothing to provide seasonal storage.
Comments are closed.
NOT A LOT OF PEOPLE KNOW THAT 
Just think, on a cloudy, rainy day, the solar output from individual sites can drop to 10%-20% of the sunny day output. You need to look at weather.
The stupid government is encouraging the building of massive amounts of BESS (Battery Energy Storage System) capacity. You could not make up the insanity of government energy policy.
Why not? They are making it up as they go along.
Again and again I come back to the tale of the Emperors Clothes….. and what makes me most angry are the ever increasing ranks of weasel and chancers needing more and more gold to make thread for the clothes that of course only clever people ( believers) can see.
No doubt about it, this is the “Get Rich scheme” that all shysters would love to operate. Given that we are currently overpaying via the piss poor negotiations carried by the “experts” in the wonderfully named Department for Energy Security, any surplus Solar or Wind that is going to be “wasted” can be sold to whoever, at whatever price they dictate and the Poor Bloody Taxpayer still pays the difference so no loss to the “producer” thanks to the CfD.
I know of no other industry that has received so much for doing so little.
We are truly Lions led by Donkeys.
I think that is being very rude to donkeys. I think more people would vote for a donkey in July than a Uniparty LibLabCon.
Being the pedant that I am with units, I think it should be:
Effectively for every MW of solar capacity, they would have to build 3 MWh of storage.
H-avoch, never mind the Solar – hiding behind the morning’s Haar til lunchtime. How do you get standby power to power up with uselssUK Weather forecasts over the SOlar array. ButWATCH that ELephant, er, e mm, I mean the HERONs …. hardly any food ( wind ) for them. No amount of extra lochs ( battery reserves) or Pylon Lines ( Canals) is going to bring in Fish -bearing water for them. Doesn’t anybody GET IT – such simple terms !
What will these solar plants be doing in Winter?
A business that can be productive only for half the day and not necessarily every day, for only half the year isn’t a business.
Solar and wind aren’t really businesses they are hobbies.
All hobbies are expensive unless somebody pays for them.
Precisely.
Solar is irrelevant, because we need the energy in the winter, and solar produces naff-all in the winter.
R
We will need more stored backup than that.
Wind and solar can disappear for 10 days (easily), especially in the winter, so by my calculations we need about 30,000 gwh.
ie: 40 gw, for ten days, times three (if we go all electric by 2050) = 29,000 gwh
The Royal Society report said 100,000 gwh, but that was thermic energy, which would be the same as my 30,000 gwh of real electrical energy.
Even if we could boost Dinorwig to 30 gwh, that is still 1,000 Dinorwigs. Where can we build those, and at what cost?
If we thought big, and built some Snowy-2s, that is still 100 Snowy-2s. We don’t have enough hills for 100 Snowy-2s. (And Snowy-2 is now projected to cost 20 billion Oz dollars, up from the original 2 billion.)
Prof McKay (government science advisor) said we should flood the Welsh Valleys and Scottish Glens, for pumped storage. But I think the Welsh and Scots may have so ething to say about that. Although Humza Useless would not have cared, as he was only concerned about Palestinians.
.Warning to any politicians here – who believed the children at the Royal Society, that the complete transition to renewables would only cost £410 billion. Think again, sunshine, my estimate was £4,400 billion. The children at the RS are fervent believers, who are trying to dupe politicians into Greenery, by saying it is cheap. And then, just like Snowy-2, these same gullible politicians will find it very hard to back out, after spending the first trillion. Think also, about the 10-fold increase in HS2 costs.
They are all at it – don’t believe them….!
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The RS were suggesting hydrogen storage, with 800 vast caverns 2,500 ft down below the Yorkshire coast. But not only is large scale hydrolysis and storage of hydrogen untried, uncertain and untested, the storage cycle is only 25% efficient. So we would need a whole raft of new renewables, just to make up for those inefficiencies. Plus another 60 x 2 gw hydrogen burning power stations in Yorkshire, just to supply emergency backup electricity. The RS children forgot to add in the costs of hydrogen’s 75% inefficiencies (again, to dupe naive politicians).
Face facts, unreliable renewables will be our downfall, much as I said back in 2004.
. ‘Renewable Energy our Downfall’
Look, dear politicians, this was easy to assess and project. Anyone with common sense, who has not been taken in by the Green religion, could have told you what needed to be done. I gave you a clear blueprint for the way forward, 20 years ago. A whole generation ago.
All those nuclear power stations could have been built by now, and we would be sitting pretty. But no – arrseholes like Blair and Cameron dithered, not wanting to look unpopular, and have left us in the shiite.
There should be a deep hole somewhere, for Blair and Cameron. Oh, and an even deeper hole for Broone selling all our gold at the bottom of the market – genius that he was…!
Ralph
Think again, sunshine, my estimate was £4,400 billion.
An estimated financial cost to achieve net zero using a UK grid powered by wind/solar and with battery storage to provide backup and stability is approx twenty five trillion £££, to be paid for by the UK population.
Chemical batteries are not possible. A battery capable of 30,000 gwh, would be the size of Coventry.
R
Storage: finite.
Outage: unbounded.
Chemical batteries are not possible.
With current technology, there are several aspects of net zero that are technically feasible but are impractical; high cost typically being a major part of the impracticality. However, these aspects should be costed to demonstrate how impractical net zero is.
… the size of Coventry.
The back of my envelope suggests bigger than Coventry if the design is based on Cottingham:
If 30 000 GWh of stored electricity is required
Cottingham battery rated at c200MWh
Cottingham surface area = “three football pitches” , the Hull Daily Mail https://www.hulldailymail.co.uk/news/hull-east-yorkshire-news/inside-huge-battery-farm-bringing-8295782
Football pitch size varies, can use 5000 m^2 (football = soccer)
There are now 3 projects along the Loch Ness/Lochy rift valley: Coire Glas – 30GWh/1.5GW; Red John (2.8GWh/450MW), renamed since it was acquired by Statkraft:
https://projects.statkraft.co.uk/loch-na-cathrach/
and now another 30GWh/2GW on Loch Ness
GEE unveil plans for 30GWh pumped hydro facility (current-news.co.uk)
Given that these projects will all have incentive to pump and to generate at the same time this is likely to result in much more churn of the lake: they can’t all pretend that the effect will be just a couple of inches. I expect Highlanders will start objecting soon if not yesterday. They’re going to need 4GW of transmission in and out too – more pylons.
Since Coire Glas is costed at £2 billion, sufficient stored backup (30,000 gwh) to keep the lights on, will cost £2 trillion. Before cost overruns…
R
... sufficient stored backup (30,000 gwh) ...
I’m attempting to reconcile your view that 30,000 GWh (which is 30 TWh) is sufficient storage when the Royal Society report refers to 100 TWh of storage (p81 of the report) :
The cost of providing an electricity system of
the kind envisaged in this report should be
analysed in detail. 200 GW of wind and solar
capacity and 100 TWh of storage capacity will
be needed,
I recognise the difference between TWh energy stored as electricity e.g. in a battery and TWh energy stored as fuel e.g. a coal-heap for a coal-fired power station. What I can’t see is where this is detailed in the Royal Society report i.e. what TWh are the Royal Society referring to? Stored electricity or stored fuel?
Feeble excuse: to be fair to me, I’ve only skimmed the report.
Micky.
It is note b on page , which says:
”This is the thermal energy content of the stored energy expressed in terms of the Lower Heating Value – see the Glossary.”
This is pertinent with hydrogen storage, because they claim 33% efficiency (I think more like 25% efficiency).
Whatever the case, that 100,000 gwh comes down to 30 or 25 thousand gwh of real usable energy.
Thanks ralfellis, I found that on page 5. I’ll now need to understand “Lower Heating Value” !
Does anybody know why we continue with solar/wind/battery supply when the only guaranteed output is as near to zero as makes no difference ?
Came across an interesting report by an Australian outfit called Climate Energy Finance entitled ‘2023 China Electricity Mix Yearly Review. Massive Decarbonisation Progress is Key Economic Stimulus’ (30th Jan 2024)
They reported that China’s solar installation reached 609GW by the end of 2023. 20.9% of installed capacity. Then without blushing said solar’s share of electricity generation during 2023 was just 3% “reflecting low solar capacity utilisation rates”
A factor of ~1/7th or around 14% beats most solar in the UK. Perhaps a good site in the SW can match it. Chinese wind is a serious underperformer. Most of China is not that windy. Much of the capacity is not grid connected: it has simply been erected to meet the plan.
There are all sorts of issues with large scale solar. Big farms can fall under the same cloud front with alarming speed, resulting in rapid drops in output that require significant local grid stabilisation: the same effect in reverse can occur as the cloud passes over. This alone will make battery installations almost compulsory.
We’re already seeing the effect of sunny summer Sundays pushing prices into negative territory. For now, exports tend to be limited – suggesting the Continent also mostly generates surpluses in these conditions, and the evidence is that any wind generation is bearing the brunt of the need for curtailment, because solar is not connected at the transmission level controlled by the Grid, which has limited control over solar output, despite their attempts to set up payments for solar curtailment. Last summer, the Grid paid Dutch solar farms up to £550/MWh to curtail rather than export via BritNed.
Maximum output tends to be of the order of 70% of installed capacity, so 70GW of solar could be expected to generate up to 50GW when demand is under 30GW, and some other generation is “must run” for grid stability reasons, so peak surplus output is likely to exceed 30GW, which sets the lower limit on how fast any storage must be capable of charging. It would be even more on a windy and sunny day of course. The planned 4GW/63GWh of pumped storage around Loch Ness is not likely to be useful when the surplus is dominated by solar farms in the South. See the locations of AR5 awarded plant here:
https://datawrapper.dwcdn.net/N76ms/3/
Batteries are in business to make money, and therefore they will try to discharge at the best prices preferentially. That will mean approaching and after sundown in most cases. Given that they must be sized to absorb a surplus, that capacity will also be available for discharge. However, competition may rather cannibalise their revenues, as has already happened to other battery revenue streams such as fast frequency response grid stabilisation, which once earned $17/MW/h of availability, but now struggle to earn 10% of that.
‘Storage’ is not “backup.”
It’s a trick.