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When it comes to their demand for electricity, the power consumer has a couple of basic needs: when they hit the light switch they assume illumination will shortly follow and that when the kettle is kicked into gear it’ll be boiling soon thereafter. And the power consumer assumes that these – and similar actions in a household or business – will be open to them at any time of the night or day, every day of the year.
For conventional generators, delivering power on the basic terms outlined above is a doddle: delivering base-load power around the clock, rain, hail or shine is just good business. It’s what the customer wants and is prepared to pay for, so it makes good sense to deliver on-demand.
But for wind power generators it’s never about how much the customer wants or when they want it, it’s always and everywhere about the vagaries of the wind. When the wind speed increases to 25 m/s, turbines are automatically shut-off to protect the blades and bearings; and below 6-7 m/s turbines are incapable of producing any power at all.
It’s no wonder that the Brits have noticed that wind power is nothing more than a sick joke.
Even with the most geographically widespread grid-connected set of wind farms in the world (the 3,669 MW of wind power capacity connected to Australia’s Eastern grid across SA, Victoria, Tasmania and NSW) there are dozens of occasions each year when total wind power output struggles to top 2% of installed capacity – and hundreds when it fails to muster even 5%:
The Wind Power Fraud (in pictures): Part 1 – the South Australian Wind Farm Fiasco
The Wind Power Fraud (in pictures): Part 2 – The Whole Eastern Grid Debacle
And see our posts here and here and here.
Now, if the power consumer was given advance warning of when these total output failures were going to occur, they might simply reconsider their selfish demands of having illumination after dark or that hot cuppa in the morning. That way, they might still consider wind power as some kind of “alternative” for conventional power?
But, so far, power consumers remain stubbornly selfish; wedded to the idea that when they hit the switch, their power needs will be satisfied that very instant (the cheek, hey?).
And that’s where the myth about wind power being some kind of “alternative” falls in a heap.
Unless you’re prepared to live like stone-age hermits, power delivered at the whim of mother nature (which in practical terms means no power at all, hundreds of times each year) is NO alternative for power delivered on-demand; anytime of the day or night; every single day of the year – and in volumes sufficient to satisfy all consumers connected to the same network, at the same time.
It was only a matter of time before the data (you know, the stuff that ‘inconvenient’ facts are made of) came to light and exposed the great wind power fraud for what it is: Britain, no exception.
Derek Partington has been perusing the woeful numbers over the last few years and produced the dismal results in this paper: Intermittency of UK Wind Power Generation 2013 and 2014
Derek has a degree in Physics; was formerly a Chartered Engineer and a member of both the Institute of Physics and the Institute of Measurement and Control. He worked for British Steel for 30 years and Local Government for 10 years, in both cases as a Project Manager and Business Analyst; and has been undertaking research into wind turbines for over 6 years.
Here’s the thrust of Derek’s wind industry killing paper.
Intermittency of UK Wind Power Generation 2013 and 2014
Grid, UK
Derek Partington
April 2015
Executive Summary:
This summary covers the principal findings of an analysis of electricity generation from all the UK wind turbines farms which are metered by National Grid, covering the period from January 2013 to December 2014.
The analysis shows:
Monitored wind turbine output (as measured by the National Grid) increased from 5,894MW to 8,403MW over the period.
The average capacity factor of all monitored wind turbines, onshore and offshore, across the whole of the UK, was 29.4% in 2013 and 28.8% in 2014.
The monthly average capacity factor varied from 11.1% (June 2014) to 48.8% (February 2014).
The time during which the wind turbines produced less than 10% of their rated capacity totalled 3,278 hours or 136.6 days over the two year period.
The time during which the wind turbines produced less than 5% of their rated capacity totalled 1,172 hours or 48.8 days over the same period.
Minimum wind turbine outputs averaged 132MW (1.8% of capacity) in 2013 and 174MW (2.1%) in 2014 as measured over 30 minute intervals.
Variations in output of 75 to 1 have been observed in a single month.
Maximum rise and fall in output over a one hour period was about 1000MW at the end of 2014 with a trend increase of about 250MW per year as measured over four years.
There is no correlation between UK wind turbine output and total UK electricity demand, with output often falling as demand rises and vice-versa.
The conclusions to be drawn from the analysis are that the increase in nominal capacity:
Does not increase the average wind turbine capacity factor.
Does not reduce the periods of low (less than 10% of installed capacity) or very low (less than 5%) output.
Does not reduce intermittency as measured by average monthly minimum output.
Does not reduce intermittency or variability as measured by maximum rise and fall in output over one hour period.
Does not indicate any possibility of closing any conventional, fossil-fuel power stations as there is no correlation between variations in output from wind turbines and demand on the Grid.
Therefore, based on the above, there is no case for a continued increase in the number of wind turbines connected to the Grid, or for the associated subsidies for wind energy, since this is an ineffective route to lower carbon dioxide emissions.
In April 2013 The Scientific Alliance published my analysis of electricity generation from all the UK wind turbines which are metered by National Grid, covering the period from January 2011 to December 2012.
This analysis showed:
The average capacity factor of all monitored wind turbines, both onshore and offshore, across the UK was 33.2% in 2011 and 30.7% in 2012
The average capacity factor in any given month varied from 16.2% to 50.8%.
The time during which the wind turbines produced less than 10% of their rated capacity totalled 3,165 hours and the time during which the wind turbines produced less than 5% of their rated capacity totalled 1,200 hours.
The output from wind turbines was extremely intermittent with variations by a factor of 10 occurring over very short periods.
Despite the fact that wind turbines only operate at about 30% of rated capacity on average and are exceedingly variable in their output, leading to long periods of very low output, the wind turbine fleet in the UK has increased significantly since 2012, driven entirely by government policy.
On 5 January 2015 renewableUK (the organisation representing the wind industry) headlined “Electricity needs of more than a quarter of UK homes powered by wind in 2014”.
They said that official statistics from National Grid showed that record amounts of electricity were generated by wind power in 2014:
Wind generated enough electricity to supply the needs of more than 6.7 million UK households last year; a 15% increase on the amount generated in 2013 (up from 24.5 terawatt hours to 28.1TWh in 2014) – just over 25% of all UK homes all year round.
Wind farms feeding into the grid, as well as smaller sites connected to local networks, provided 9.3% of the UK’s total electricity supply in 2014, up from 7.8% in 2013.
Other records were broken in December, with a new monthly high of 14% of all UK electricity generated by wind, beating the previous record of 13% set in December 2013, as well as a new quarterly record of 12% of electricity from wind in the last 3 months of 2014, breaking the previous record of 11% set in Q1 of 2014.
renewableUK continue to state on the Onshore Wind page of their website, “Onshore wind farms reduce CO2 emissions, provide energy security, and contribute to the local and national economy.
“The page also states, “Onshore wind works well in the UK because of the excellent wind resource. It has also become one of the most cost effective forms of renewable energy, providing over 5,000MW of capacity. A modern 2.5MW (commercial scale) turbine, on a reasonable site, will generate 6.5 million units of electricity each year – enough to make 230 million cups of tea.”
On 12 January 2015, the renewableUK home page gave figures “Powered by Wind”: Energy Produced 29,190,769 MWh, powering the equivalent of 6,963,447 homes and giving CO2 reductions (pa) of 12,552,031 tonnes.
These are very impressive figures if taken at face value, but what are the facts behind these statements – can we rely on wind turbines to power our homes and offset the annual release of carbon dioxide from conventional coal and gas burning power stations?
My previous report showed that this could only be true if the wind blew constantly but it does not, it blows very intermittently.
I have continued to analyse the output from the UK wind turbine fleet during 2013 and 2014, as measured by the electricity fed into the grid, in order to determine whether more turbines being brought into operation:
Improves average capacity factors
Reduces the periods of low or very low output
Reduces intermittency
Makes it possible to close any conventional, fossil-fuel power stations by making up for additional demand on the grid at peak times and, based on the analysis, to conclude whether wind turbines in the UK are making any significant contribution to a reduction in CO2 emissions.
Installed and Monitored Capacity
The installed capacity of wind turbines in the UK was quoted as 11,978MW by renewableUK on 12 January 2015 (7,936MW onshore and 4,042MW offshore). By comparison, on the same date the NETA (New Electricity Trading Arrangements) website quoted a capacity connected to the grid of 8,403MW, i.e. only 70% of the total installed capacity quoted by renewableUK.
This ratio has not changed over the years – at the end of 2011 the installed capacity of wind turbines in the UK was quoted as 5,772 MW whereas the monitored capacity, i.e. that monitored by the National Grid, was 4,006 MW. The equivalent figures for the end of 2012 were installed 7,777 MW, monitored 5,705 MW.
This analysis uses the NETA data throughout – the capacity connected to and monitored by the grid.
From the data on the NETA website, it is not possible to distinguish between onshore or offshore wind generation, or that from different parts of the UK. However, as this report covers the overall generation picture across the UK and does not break it down by region, this is of no consequence.
Do more wind turbines improve average output?
The average monitored capacity in 2011 was 3,340MW and the average output was 1,109.5MW giving a 33.2% capacity factor. In 2012 the equivalent figures were 4,696MW monitored by the grid, with an average output of 1,439.5MW or a capacity factor of 30.7%. The data points for each 30-minute period as monitored by the grid are averaged over the full month and a figure for output as a percentage of monitored power is calculated.
The figures show a significant variation in the average monthly capacity factor. The July average was 13.7% and that of December 46.7%. So even monthly averages vary by a factor of more than 3, a similar figure to that noted for 2011 and 2012.
Again the figures show a significant variation from month to month, the June figure being the lowest at 11.1% and February the highest at 48.8% – an increase in variation from month to month of almost 4.4 to1. Therefore from the data analysed the answer is “No, more wind turbines do not, on average, improve the average output.”
This despite there being 2.5 times increase in the installed (average) capacity from 2011 to 2014.
In fact, month to month variation, even in output averaged over the month, has increased significantly in 2014 compared with the previous three years.
If this is to be expected, simply because the installed capacity has increased, then the variation in output may be expected to increase still further as more turbines are added to the Grid, although at this stage we could equally well assume that this is primarily an artifact of the inherent variability of the wind resource.
Do more wind turbines reduce periods of low or very low output?
I have taken low output as being less than 10% of installed capacity and very low output as being less than 5% of installed capacity. Any percentage could have been chosen, but I believe that these are reasonable figures if one is to place any reliance on a sustainable source of supply.
In 2011 there were a total of 485.5 hours, or 20.2 days when output from the total UK wind turbine fleet fell to less than 5% of monitored capacity. The equivalent figures for 2012 were 714.5 hours or 29.8 days.
In 2011 there were a total of 1,370 hours, or 57.1 days when output from the total UK wind turbine fleet fell to less than 10% of monitored capacity. The equivalent figures for 2012 were 1795.5 hours or 74.8 days.
The table below gives the same data for 2013 and 2014, i.e. the total hours per month and per year where total output fell to less than 5% and less than 10% of installed capacity.
The data show no significant difference between the 2011 and 2013 periods and the 2012 and 2014 periods.
It can be seen that there are significant deviations from month to month. In the “worst” month, September 2014, the output from the total UK turbine fleet was less than 5% of their installed capacity for almost 25% of the time. In the same month the turbines failed to reach 10% of their capacity for over 62% of the time.
The graph for September 2014 is given below.
Over the 2-year period there was a total of 1,172 hours, or 48.8 days, when the output was less than 5% of nominal installed capacity.
This compares with 50 days over 2011 and 2012.
Looking at where output was less than 10% of installed capacity, for the two year period this was 3,278 hours , or 136.6 days compared with 131.9 days over 2011 and 2012.
It should be noted that 136.6 days is well over 4 months in total over the 24 month period.
Therefore from the data analysed the answer is “No, more wind turbines do not reduce periods of low or very low output”. (Note: low output is a function of natural variation in the strength of the wind – which, of course, is not influenced by having more wind turbines).
Do more wind turbines reduce intermittency?
The Oxford English Dictionary defines intermittent as “occurring at irregular intervals; not continuous or steady”. It is obvious that wind in the UK intermittent. It is not steady – sometimes the wind blows strongly, sometimes weakly and sometimes not at all. But here we are not concerned with the strength of the wind but its effect on the output of the UK wind turbine fleet.
To demonstrate the intermittency I have plotted the total UK wind turbine output for every month over the 24 months studied.
The graph on the following page shows data from a typical month, from March 2014.
It can be seen that during March 2014, the wind was always blowing somewhere in the UK as the output from all the wind turbines feeding the National Grid never fell to zero. However, the output varied dramatically from day to day, with a minimum output of 75MW and a maximum of 5,582MW – a variation of almost 75-fold.
This graph is quite typical and detailed graphs, with additional data, are given for each of the 24 months analysed in the appendix.
Intermittency can also be presented as daily minima and maxima in any month as shown in the bar chart below for August 2014. This is again a typical month where the average capacity factor was 27.5%.
On a single day, 2nd August, the variation from minimum to maximum is almost 30-fold.
The following table gives the minimum output during each month over the 2 years for which the data was analysed.
Therefore the assumption that the wind is always blowing somewhere in the UK may be true, but at times it is barely blowing enough to generate any significant energy.
In 10 out of the 24 months monitored, the minimum output dropped to 1% of capacity or less at some time. It should also be noted that the minimum output levels have not significantly changed since 2011, even with more wind turbines being installed. The equivalent average minima for 2011 and 2012 were 2.1% and 1.5% respectively.
As can be seen the maximum rise and fall has increased significantly as operational capacity has increased. This is the variation which the grid has to cope with, bringing in conventional fossil fuelled stations when output falls and taking them off line when it rises.
The above data can be plotted to give a trend showing the year on year increase.
It can be seen that The National Grid is now having to cope with variations in output (intermittency) of over 1,100MW over one hour periods. It can also be seen that this variation is increasing by about 250MW per year.
It should also be noted that 1,100MW is 13% of the installed capacity and is over 40% of the average monthly output in 2014.
The peak fall over one hour was 2,153MW in March 2014, a figure which is likely to be exceeded as more turbines are connected to the grid.
Therefore, from the data analysed the answer is “No, more wind turbines do not reduce intermittency. In fact using two alternative measures, minimum output during the month and variation in output over 1 hour, then more turbines increase the impact of intermittency”.
Do more wind turbines make it possible to close any conventional, fossil-fuel power stations by making up for additional demand on the grid on peak times?
If the variation in output matched the increase or decrease in demand on the grid, then there would be no need for back-up in the form of conventional, fossil-fuel power stations.
In order to see if output from wind turbines in any way matches demand, the total output has been plotted against demand on the grid over the last seven months of 2014. In order to fit the graphs on the same scale, UK wind turbine output has been plotted alongside grid demand divided by ten.
A typical week, from October 2014, is shown below. As expected, there is no correlation between output and demand. The output varied over the week from a high of 6,000MW on 6 October to a low of 200MW on 12 October with no form of repetitive pattern in between.
The graph above does show a pattern on some days where output from wind turbines falls as demand rises and vice versa, which is not atypical. In fact over Christmas Day 2014, if wind were relied on to cook the turkey, then there would have been a public outcry as output dropped steadily from over 6,000MW on Christmas Eve to under 200MW on Boxing Day.
Therefore, from the data analysed the answer is “No, more wind turbines do not make it possible to close any conventional fossil fuel power stations”.
As expected, analysis shows that there is no correlation between variations in output from wind turbines and demand on the Grid. Often the opposite is true – when demand rises, output from wind turbines falls and vice versa. This has a significant negative effect as back-up has to be provided from conventional, fossil-fuel power stations not only to cater for increase in demand on the Grid at peak times but also to cover for any possible fall in output from the UK wind turbine fleet at the same time. (It is understood that fossil-fuel generators being run in stop-start mode to provide this back up are very inefficient and may be producing significant additional carbon dioxide than when operating in their designed steady state.) So, taking some of the renewableUK statements:
“Electricity needs of more than a quarter of UK homes powered by wind in 2014” – should this be “Electricity needs of more than a quarter of UK homes powered by wind in 2014 some of the time”?
“Wind farms feeding into the grid … provided 9.3% of the UK’s total electricity supply in 2014” – should this read “Wind farms feeding into the grid … provided 9.3% of the UK’s total electricity supply in 2014 when averaged over the year.”
“Other records were broken in December, with a new monthly high of 14% of all UK electricity generated by wind” – should this be counterbalanced by “but in June 2014 electricity generated by wind was only one quarter of this figure”.
“Onshore wind farms reduce CO2 emissions, provide energy security….”. Taking the analysis in this report, and the previous one, there is no basis for this statement.
There is patently a need to provide back-up for wind turbines which are feeding into the Grid and therefore CO2 emissions may possibly be increased rather than decreased as conventional, fossil-fuel power stations have to be operated inefficiently in order to provide this back up. Similarly there is no energy security if output can fall from over 6,000MW to under 200MW over a 42 hour period as it did over Christmas 2014.
Based on the above, I would like to see evidence that any conventional power station has been able to be closed down as a result of the introduction of over 8,000MW of wind turbine capacity feeding into the National Grid. Similarly I would like to see evidence of reductions in CO2 emissions through the introduction of wind turbines where a holistic approach to meeting the demand on the Grid is taken into consideration.
Conclusions
Over the period studied, January 2013 to December 2014 inclusive, wind turbine operational capacity connected to the UK Grid has increased from 5,894MW to 8,403MW. The operational capacity in January 2011 was 2,490MW; therefore there has been an increase of almost 3.4x over the four year period.
The conclusions to be drawn from the data analysis are:
An increase in the operational capacity does not improve average output. In fact the average monthly capacity factor has fallen over the periods studied, dropping from 33.2% in 2011 to 28.8% in 2014.
An increase in the operational capacity does not reduce the periods of low or very low output as measured by the number of hours per year when output was low (less than 10% of installed capacity) or very low (less than 5% of installed capacity). There is a variation from year to year but no pattern emerges. The mean low output over the four years was 1,617 hours/year with a standard deviation of 197 hours/year and the mean very low output was 599 hours with a standard deviation of 96 hours.
An increase in the operational capacity does not reduce intermittency. If taken as a measure of intermittency, the average monthly minimum expressed as a percentage of installed capacity was 1.9% with no significant variation from year to year.
Taking maximum rise and fall in output over one hour period as a further measure of intermittency, the National Grid is now having to cope with variations in output of over 1,100MW over one hour periods, with this variation increasing by about 250MW per year.
This is very significant as it represents the changes in output which the Grid has to cope with and which has to be compensated by conventional fossil fuelled power stations.
An increase in the operational capacity does not indicate any possibility of closing any conventional, fossil-fuel power stations as there is no correlation between variations in output from wind turbines and demand on the Grid. Often the opposite is true – when demand rises, output from wind turbines falls and vice versa.
This has a significant negative effect as back-up has to be provided from conventional, fossil-fuel power stations not only to cater for increase in demand on the Grid at peak times but also to cover for any possible fall in output from the UK wind turbine fleet at the same time.
Therefore, taking the four criteria above, there is no case for a continued increase in the number of wind turbines connected to the Grid.
As stated in my previous report, it is incumbent upon the Government to ensure that the British consumer is getting value for money from industrial wind turbine installations and that they are not just paying subsidies to developers and operators (through ROCs) whilst getting nothing back in return in terms of CO2 emission reductions through the supplanting of fossil-fuelled power generation.
Based on the results of this and my previous analysis I cannot see why any policy for the continued increase in the number of wind turbines connected to the Grid can be justified.
Derek Partington
Derek’s previous paper can be found here: Intermittency of UK Wind Power Generation 2011 and 2012
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