BBC’s Solar Power Misinformation
By Paul Homewood
More disinformation from the BBC:
https://www.bbc.co.uk/news/science-environment-64553915
Amidst the backslapping about how wonderful solar power is, the BBC present this graph:
WOW!! Most people reading this would believe that electricity from fossil fuels is declining rapidly, while solar and wind power now claim a share well over 20%.
Most of those same readers would be unaware what the BBC mean by “capacity”, or that “capacity” and “generation” are two totally separate and different things.
And when we look at generation, we can see how badly misled those readers have been:
BP Energy Review
Far from being major players, wind and solar together only supply 10% of the world’s electricity. And since 2010, the increase in fossil fuel generation has exceeded that of wind and solar.
A rather different picture to the one the BBC would like you believe, I think you might agree!
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NOT A LOT OF PEOPLE KNOW THAT 
A very pertinent comment from the Guido Fawkes website:
” ‘False truth’ seems to be a perfect description of how the BBC operates. Rarely does it outright lie. What it does is manipulate narratives by omitting crucial facts. While a person listening to a BBC news report might hear true facts, they will invariably be given a ‘false truth’.”
Is that true? Or did you hear it on the BBC?
Lying by omission – their normal policy. Closely allied to cherry-picking to avoid inconvenient data.
That’s the same as FakeNews
Trump uses the term to indicate the news item is misleading, rather than necessarily an outright lie
Reliable info on panel efficiency and longevity is long overdue. We study Gridwatch with interest.
This is disgraceful. The BBC goes from very bad to much worse.
And the government cheats on wind and solar, giving them business, taking it from the others.
Wind/solar do not compete in the marketplace; government gives them their place.
I think that I’m a fairly intelligent man and even I can figure out the difference between capacity and actual – so I assume that the bright sparks who put this presentation together also knew the difference. The fact that they – or, in their defence, their management – then went ahead and mis-appropriated their analysis is an outright fraudulent use of data and should be condemned by BBC management, unless they too are part of the fraud.
And fraud is what it is. There is no other word to describe it. Fraud is a criminal offence….
It’s their ‘truth’…
Hourly records of WQeather-Dependent “Renewables result in the following Productivity CapacProductivity measued hourly for 2021 – 2022
Germany – UK – France
2021 2022
onshore wind power 19.3% 26.2
offshore wind power 29.1% 36.9
combined wind power 21.0% 26.1
solar PV power 9.4% 13.5
combined Weather-Dependent power 15.8% 21.6
conventional generation 90.0% 90.0%
For some more graphs, see here:
https://edmhdotme.wordpress.com/2021-european-wind-drought-analysed/
https://edmhdotme.wordpress.com/2022-weather-dependent-renewables-in-germany-uk-and-france/
So why the difference then, and what is “capacity”?
Capacity is the nameplate capacity of a generator, assuming it runs at 100% all the time. Generation is the actual electricity produced.
Whereas a nuclear or gas power station can run close to 100% most of the time, a solar farm can only produce at about 10% of its theoretical capacity, because the sun does not shine at full power all the time.
Put another way a 1000 MW gas plant would generate ten times as much electricity as a 1000 MW solar farm
For wind there is a further complication. This is difficult to explain using the written word.
The energy available depends on the cube of wind velocity. This is from the equation for kinetic energy half mass times velocity squared.
But the mass also depends on the velocity of the wind. Imagine that the wind doing the generating is a cylinder passing through the blades. The mass of air is the density multiplied the volume. The volume of the cyldiner is Pi times square of radius multiplied by length of the cylinder. The length of the cylinder is velocity multiplied by the time. So the final result is that the energy is
Half Pi times radius squared times velocity times air density times velocity squared
Every thing is constant apart from velocity. So the energy is a Constant times velocity cubed.
The optimum output for most wind turbines is around 12-14m/s (around 29mph)
So at 6m/s there is only an eighth of the energy available. As the wind velocity drops further the energy available falls so much the turbine stops producing electricity even in a 7mph wind.
In practice the behaviour of a wind turbine doesn’t follow the limits of the theoretical optimum. It needs a slight breeze to turn at all, and then it does so rather inefficiently, with much of the energy spent on overcoming friction and inertia. Efficiency improves up to the sweet spot, but typically peaks at no more than 45% of the energy of the wind. There is a theoretical limit known as the Betz limit which arises because you cannot stop the wind dead once it has passed through the turbine (which would be needed to extract all the energy), which is 16/27ths of the wind energy, or about 58%. So peak efficiency is in fact around 75% of the theoretical maximum.
The generator is usually sized to reach full power at the higher end of the sweet spot. Once the generator has reached full power, the turbine produces that, with the blades being feathered progressively to avoid overstressing the system. Eventually the stress risk becomes too high, and the generator cuts out altogether. The efficiency curve (with associated power outputs) looks like this:
https://datawrapper.dwcdn.net/GqyyC/1/
The chimera of wind turbines is finally coming into view now that they are poised to make significant, MANDATED, contributions to the grid. In the past, very large fossil or nuke fueled power plants provided immense INERTIA against the insignificant wobble and flicker of wind mills. As wind will be becoming a significant contributor to grid supply–currently less than 10%–some accommodation must be found to provide grid supply INERTIA to smooth out the weak and wobbly wind output, along with all the electrical noise and chaff outputted from solar panels and their related power machinations–chop, chop, chop. Enter ABB, with there Synchronous Capacitors to be added to wind supplied grids, to provide both voltage and frequency stabilization. “What was old is new again”–Ecclesiastes? Look up these hugely parasitic devices on the ABB website. The immense water-to-air cooling systems will give you an idea of all the wasted power needed to make the new GREEN energy palatable to the local grid.
Ben:
Air density can change quite significantly. It is normally quoted as 1.225kg/m^3 in standard wind turbine power curves, which assumes 15 C and sea level 101.325 kPa pressure and dry air. The gas equation PV=nRT can help with the calculations. The average molecular weight of dry air is around 29, but water vapour can drop the density to around 1.217kg/m3. Boost the temperature to 30C and the density falls to 1.146kg/m3. Drop the pressure as in a tropical depression to say 980millibar and we’re down to 1.108kb/m3. Altitude also sees pressure drop
P=P0.exp(-gMh/RT) where h is altitude M is kg/mol g is gravity
so turbines erected on a mountain pass ridge will face a much lower pressure, and even modern hub heights of 150m make a difference (with blade diameter affecting the top even more). The idea is that wind speed compensates.
Moving in the other direction, a cold (-20C) winter high (1030millibar) with dry air would see the density rise to 1.417kg/m^3. You could easily be looking at a 50% variation between extremes. When you look at empirically measured turbine outputs vs wind speed you will see a good spread of points around the theoretical standard conditions curve. These weather variations are a good part of why.
Thanks for the follow ups to my original comment.
I was aware that density of air was a variable and also changes with altitude but the major variable is velocity as the density is a linear relationship velocity is cube.
I’ve never seen an optimum wind speed of less than 12m/s quoted for a large turbine. Although manufacturers no longer seem to make that information available online to the public, presumably it’s not improving.
But the bottom line is you can’t get out more than is available.
For a Siemens Gamesa SG22-122 which has a swept area of 11,690 m². I make it 12,372,696 Joules/sec at 12m/s and density of 1.225kg/m^3 (Joule is equal to 1 kg m^2 / s^2). This is 12.4MW (1W = 1J/s) and the turbine is rated at 2.2MW. I’ve never done this calculation before so if I haven’t got it wrong that’s not a great extraction rate, less than 20%
And when the wind speed really drops or disappears completely, the windmills actually absorb energy when they are rotated to stop brinelling of the bearings.
Ben:
I think that particular turbine is designed for low wind speed environments, so its maximum efficiency is at a rather lower wind speed. That may be more valuable to turbines that sell at market prices (rather than a fixed CFD), which will be low at high wind speeds when most turbines are at high output but much higher as the wind abates. This page explains:
http://drømstørre.dk/wp-content/wind/miller/windpower%20web/en/tour/wres/cp.htm
The guide to the calculator on the next page provides a handy summary of factors with links back to more detailed explanations.
http://drømstørre.dk/wp-content/wind/miller/windpower%20web/en/tour/wres/guidep.htm
I can thoroughly recommend the whole tutorial, although it is now 20 years old. It goes into the factors that affect the economics and practicalities of wind turbine design, throwing up the at times counter-intuitive oddities that arise. Modern turbines are of course much bigger, but we are starting to run into practical design limitations.
The Rampion windfarm is just off shore from the Shoreham gas power station. Both have a nameplate capacity of about 400MW.
The windfarm has a capacity factor of ~35%, which means it generates the full time equivalent of 140MW, however it is not dispatchable i.e it is at the whim of the weather, sometimes it will produce nothing at all, usually in the coldest weather, occasionally it will produce more than 300MW, but sometimes when the power may not be required and it will have to be constrained (dumped).
The power station has a capacity factor in excess of 90%, the full time equivalent of 360MW or more, and it is more controllable up and down to meet demand.
Oh, Rampion takes up 72 sqkm, the power station has the footprint of a very big shed!
Paul has explained it very well, but to add emphasis consider that the Heysham 2 nuclear power plant holds the world record for continuous operation of 940 days.
https://world-nuclear-news.org/C-Record-940-days-of-continuous-operation-for-Heysham-unit-1609164.html#:~:text=De%20Rivaz%20said%20unit%202,nuclear%20reactors%20in%20the%20UK.
Solar plants don’t work in the dark (a daily event) and wind turbines only work when it is either windy or not too windy and then in only a very limited manner. https://energyeducation.ca/encyclopedia/Betz_limit#:~:text=The%20Betz%20limit%20is%20the,the%20turbine%20and%20generate%20electricity.
Heysham no longer has that honour. My faulty memory was that one of the CANDU reactors took the crown fairly soon after Heysham, but I could well be wrong.
https://world-nuclear-news.org/Articles/Kaiga-1-completes-record-breaking-run
my car has the capacity to provide 150 mph however in practice my journeys are somewhat slower……………….
I object to the smooth line for solar pv capacity: it is DOUBLE-OUGHT ZERO most of the time.
Hourly records of Weather-Dependent “Renewables result in the following
Germany – UK – France data gridwatch etc
Productivity Capacity%
measured hourly productivity – capacity percentage for 2021-22
2021 2022
onshore wind power 19.3% 26.2%
offshore wind power 29.1% 36.9%
combined wind power 21.0% 26.1%
solar PV power 9.4% 13.5%
Weather-Dependent power 15.8% 20.6%
conventional generation 90.0% 90.0%
2021 was a poor year for “Renewables” but 2022 was much improved
The extent of the actual measured variability for details see:
https://edmhdotme.wordpress.com/2021-european-wind-drought-analysed/
https://edmhdotme.wordpress.com/2022-weather-dependent-renewables-in-germany-uk-and-france/
https://edmhdotme.wordpress.com/3-graphs-say-it-all-for-renewables/
This is the scale of annual variations that are tolerated by the National Grid in providing a consistent service.
Would anyone sane buy a car costing about 10 times the normal price to buy and run, that can only work one day in five, when you never know which day that might be ? And then insist that its technology is the only way to power the whole economy.
Especially if it was an EV – which would just increase the element of uncertainty.
Yet, there are so-called intelligent people sitting in government over us who think it the way forward: NAY! The way to be World Leaders!! Sheesh!
They are world leaders Harry. The U.K. is the world leader in BS.
Piss Poor Ejukayshun.
Local news is just as bad now.
Hydrogen is a “fuel source”.
And it will solve the “climate Armageddon”.
https://www.theargus.co.uk/news/23312047.hydrogen-strategy-approved-brighton-surrounding-areas/
Paul,
Deliberately or inadvertently (or perhaps through plain ignorance) the media regularly confuses electricity and energy. I suspect the use of nameplate capacity is a deliberate tactic. I looked into this tactic a little over a year ago, here:
They also confuse power and electricity. I suspect most of the media does not know the difference between energy and power (or even that they are not the same).
Not telling the truth–without lying. Well done, BBC. You should work for he Harris/Biden Ministry of Truth. Oh, how the once mighty have fallen, led astray by the emotional rantings of a petulant, chubby, paid-activist teenage girl. Like I said, Brandon is always looking for a few, not so good, men.
I have sent a complaint to the BBC. We should all do the same complaining that capacity does not equal actual generation or even expected generation.
Let me lift a corner on some of the methodology that allows extravagant claims about modelled renewables futures.
Here’s a chart of historic quarterly UK solar average capacity factors, together with a rolling annual average. Tacked on the end is a supposed worst case forecast from EMBER for potential in 2030, used in their modelling of a renewables grid in their recent study. Not only is the annual average higher than anything in the historical record, but the seasonal pattern is not very challenging, with much higher output in Q1 and Q4 and no big early summer peak to create regular large midday surpluses.
Here’s a similar chart for onshore and offshore wind. Again their worst case is better than the best in the real history, and the seasonality is unchallenging. Dig deeper and you find that the length of wind lulls is also rather less than often occurs in the history. Because these assumptions are deeply embedded in the detailed data, only curious minds like mine even think to dig around.
I recently found what appears to be a very lengthy period of almost no wind at the poster boy El Hierro system using wind and pumped hydro in the Canaries – they went most of December being almost entirely reliant on their diesel generators. This is the kind of reality that should be in renewables models.
Not only is the annual average higher, it also smooths out the intermittency of renewables.
Fixed it. When your power is out, you can feel good that the annual numbers are up.
Idau: Many thanks for these posts – really informative about the inner workings behind the scenes.
The assumptions for that “worst case” for offshore wind look particularly heroic. In 7 years’ time all of the existing wind turbines will, presumably, still be in service. We know that their performance degrades with time. So the models must assume an extraordinarly high CF for all new projects to counter that degradation and drag the average up by over 20% from the historic levels.
This makes me wonder what the “best case” looks like!
Why are they using tricks? Maybe they feel very insecure ..
How much energy is required to create burnable biomass ?
Biomass is a varied category, so one needs to see what they include.
In some places, land-fill gas counts, as does “waste” from sawmills or paper/cardboard facilities.
Western Oregon is noted for cheese and butter and, therefore cows. That means manure. So, the Port of Tillamook Bay has a digester:
https://www.2g-energy.com/projects/daritech-tillamook
Thank you for your reply because it shows how diverse the term biomass really is. I should of specified imported wood pellets.
I wonder how effective the scrubbers are on rubbish incinerators.
The reason being round my way the alarmists want to ban wood stoves but cannot say how much CO2 is given off from rubbish incinerators. Their hypocrisy really rankles.
I neither know nor care how much CO2 is emitted by “rubbish incinerators” (hopefully energy from waste plants).
But I remember discussions 20 years ago with senior scientists (yes, they used to exist) working in what had been the Alkali Inspectorate before this was swallowed by the Environment Agency. They showed me the results of testing at the then new Incinerator at Cleveland. Measurement of dioxins, furans, mercury and polychlorinated biphenyls at the top of the chimney confirmed the general effectiveness of the scrubbers and he stated that one would have to sit on top of the smokestack for about a year before inhaling the pollutants from a normal garden bonfire in an evening.
But GangGreen put back the energy from waste concept for most of that 20 years as they wrung their hands about dioxins etc. He advised me 20 years ago that it wasn’t worth the effort to even work up and submit an application.
Not, of course, the only or maybe even the best way to dispose of waste but much better than exporting plastic waste to 3rd World Asia & Africa and then being “shocked” at how much finishes up in rivers and the oceans.
John,
When I was a lad manure was put on the fields as a fertiliser.
In your link it says the fibre residue to horticulture users, doesn’t say if there’s fertiliser content in what’s left.
Do you happen to know?
Personally, I know more about horse manure than others, and it is incompletely digested. Thus, horse manure makes a good soil amendment, not just minerals. In a controlled situation of using the manure in a digester, things are different. I found the following:
From the USA EPA:
Digestate is the material that is left over following the anaerobic digestion process. Digestate can be made into products like:
Bedding for livestock;
Flower pots;
Soil amendments; and
Fertilizers.
When properly processed, dewatered digestate can be used as livestock bedding or to produce products like flower pots.
Digestate can be directly land applied and incorporated into soils to improve soil characteristics and facilitate plant growth. Digestate can also be further processed into products that are bagged and sold in stores. Some emerging technologies can be employed post-digestion to recover the nitrogen and phosphorus in digestate and create concentrated nutrient products, such as struvite (magnesium-ammonium-phosphate) and ammonium sulfate fertilizers.
Ed Hoskins also has a useful piece dealing (inter alia) with the nonsense of using nameplate capacity as a means of comparing different forms of electricity generation:
https://edmhdotme.wordpress.com/2022-weather-dependent-renewables-in-germany-uk-and-france/
I wonder if those who wrote this BBC article are actually even aware of the diference between capacity and output? Perhaps they are just that clueless?
They shouldn’t be and perhaps that is a problem with the BBC, it employs the wrong people, maybe from the Director General down?
Ian, I was surprised that BBC didn’t express the figures for output as ‘x,000 homes equivalent’.
With rising bills and lower consumption the homes equivalent measure is now inflating rapidly. What they always forget is that works for all forms of generation.
If you want to know how earnestly BBC science broadcasting believes in renewable fairytales, then listen to this Inside Science broadcast on 9th Feb
https://www.bbc.co.uk/programmes/m001hx4x
They really believe that renewables will offer the world abundant cheap energy, but the evidence is exactly the opposite.
Or is it me not understanding my energy bill?
Arguing about electricity is a sideshow…
“Five and half times more energy goes through the gas transmission pipes than the electricity system.”
That’s what Jon Butterworth, CEO of National Gas, had to say on whether gas is ‘redundant,’ as many people claim.
https://www.energylivenews.com/2023/02/06/the-backbone-of-energy-in-the-uk-is-gas/
The BBC quotes one of the QE prize winners saying that “”Silicon is an ideal material for photovoltaics. Abundant, non toxic and stable”
Unfortunately the same cannot be said for the making and disposal of solar panels . There is an enormous toxic lake in northern China where all the solar panels are made and solar panels are considered hazardous waste containing lead, cadmium and other carcinogenic chemicals accoding to:
https://www.cfact.org/2019/09/15/the-solar-panel-toxic-waste-problem/
The production of polysilicon for solar panels also requires huge amounts of coal, aiui.
The article was tweeted by @BBCnews and @BBCworld
There was very little discussion and no mention of the graph problem
Here’s the Save The BBC PR account tweeting it
John Dodders @dodders75 tweeted directly to the article writer @bbcAmos
who did NOT reply
BTW Jonathan Amos @BBCAmos tweeted
Well the graph does “overstate the impact” of solar