UK Weather Dependent Renewables performance in 2018


Renewable Energy Foundation in the UK have recently try updated their Renewables installation data.

This post uses  that up to date information which shows the total installation of 33.4GW of Renewable Name Plate generation capacity which provides the equivalent if 5.5GW of power to the UK Grid, a combined Renewable capacity factor of 16.6%.

The capacity percentage, or load factor, of any power generating installation is calculated as the actual electrical output achieved annually divided by the nominal maximum Nameplate output.  This article uses the measures of capacity reported in up to date time series data of UK Renewable installations.

The three main forms of UK Weather Dependent Renewable Energy in the UK, Wind Power, (Onshore and Offshore), and on grid Photovoltaic Solar Power.  In the UK these amount to ~75% of all installed Weather Dependent Renewable Energy.  The other “Renewable” energy inputs include traditional Hydro power ~8% and the remainder are other sources such as biomass, waste and landfill gas amounting to ~17%.

When announcements are made about Weather Dependent Renewable Energy installations, they are habitually reported as the full Name Plate rating usually in Megawatts and also disingenuously as the number of homes that could be supplied at their full level of power output.  So such announcements are always over optimistic. The question of Capacity Percentages  /  Load Factors are never fully explained.  So Renewable Energy announcements falsely assume that the wind blows all the time at productive speeds and that the sun shines overhead 24 hours /day.

Renewables performance

The achieved power output of Weather Dependent Renewables is crucially dependent on the vagaries of the weather, (for wind), and the weather in combination with the season and the time of day, (for solar), the useful electrical output achieved by Weather Dependent Renewables is inevitably substantially less that the maximal Name Plate rating of the installation.  Accordingly in 2018 UK Weather Dependent Renewable Energy was contributing only about one sixth of its nominal Name Plate rating to the grid.

Inevitably power production from Weather Dependent Renewables is un-coordinated with the timing of the actual demand for electricity.  In the UK, peak electricity demand occurs on winter evenings when Solar power is non-existent and when weather patterns can on occasions reduce wind speeds widely across the country to virtually nil:  anticyclonic conditions often occur widely across the country, particularly in Winter.  In addition there can be no functional coordination between the timing to the Weather Dependent Renewable Energy production and the Nation’s demand for electricity.

Traditional methods of electricity generation using Fossil Fuels or Nuclear Power are not subject to the vagaries of the weather and can produce electricity whenever needed to match customer demand.  Crucially traditional forms of electricity generation are both non-intermittent and dispatchable to meet demand whenever needed:  they thus provide a much more valuable service to maintain the gird and thus to electricity clients.

When viewed from the needs for the engineering viability of a nation’s electrical supply, without that Green influenced, Government interference, Weather Dependent Renewable Energy generation should never have been considered as functional part of the electrical generating mix.  Without the Government mandates and financial subsidies the Weather Dependent Renewable Energy industry is not a viable business and at the same time it imposes significant extra costs on the other elements of the generation Grid and thus the clients the Grid.

The substantial extra costs and the increasing likelihood of supply failure, although mandated by Government in order to pursue “Green thinking”, are in fact serious burdens on both domestic and industrial electricity consumer.  As the part played by Weather Dependent Renewable Energy grows in the Electrical grid so those cost burdens and the risks to reliability inevitably escalate.

The Renewable Energy industry could not exist without its Government mandated subsidies, consumption mandates and preferential feed-in tariffs.  In summary:  Weather Dependent Renewable Energy is both very expensive and at the same time wholly unreliable.


Calculating capacity percentages

Reporting on Weather Dependent Renewable Energy actually generated after installation is commonly presented as annual Gigawatt Hours (GWhrs) generated per year, noting the amount of electrical power actually supplied to the grid by the installation over the whole year.

Annual Gigawatt hours are easily converted to an equivalent Name plate rating in Gigawatts by dividing by the number of hours in the year (365*24) = 8760.  This output value can be compared with the original Nameplate capacity, to calculate the capacity percentage or load factor of any generating installation.

Importantly, this diminished percentage capacity factor does not account for the usefulness of the electrical power when produced to meet actual electrical demand, because of the inevitable intermittency and non-dispatchability of Weather Dependent Renewable Energy power sources.  In 2018 the combined capacity percentage for UK Weather Dependent Renewables (Wind and Solar) in 2018 was overall ~16.5%.  As the Renewable output is only ~16% of the installation, it becomes essential to ensure that there is always base load power available from other generation sources to ensure that the Grid is maintained and stable.  This process becomes ever more difficult as extra Renewable sources are added and the risk of outages becomes more likely.

Therefore capacity percentage is a generous measure of performance when comparing the usefulness of the electricity generated from Renewable sources with any dispatchable generation.

The Renewable Energy Foundation time series data for the UK 2002 – 2018

The Renewable Energy Foundation, (a promoter of Renewables and Green energy in the UK), provides comprehensive time series data on the progress of Renewable Installations in the UK since 2002.  This included Gigawatt Hour estimations of electrical output by type of generation.

The UK progress in the development of Weather Dependent Renewable installations since 2002 is shown below.

Screenshot 2019-01-04 at 11.54.40.pngEven though the UK, with its adverse weather and Northern situation, is one of the most unfavourable contexts for Solar power, there has been excessive commitment to Solar PV power, trebling the scale of installations in the period 2013 – 2015.  This has specifically shown the irrational and truly pernicious influence of Ed Davey as the then Secretary of State for Energy.

Screenshot 2019-01-05 at 11.00.53.pngIt is incredible, that as a result of his influence, the scale of Solar installations now match Onshore wind power in the UK.  But the capacity / load factors for UK Solar energy is only about 10%.   And Solar energy can never contribute at all at peak load times on winter evenings.  The resulting derisory Solar contribution to UK electrical production is clear from the capacity values shown below.

Screenshot 2019-01-04 at 10.19.53.png

For comparative purposes percentage capacities / load factors achieved since 2002 are shown.  It is clear that 2015 was a particularly productive year for UK Wind power, especially Offshore, whereas 2016 was a poor year for wind power.  In 2017 the output from wind power recovered somewhat. However by 2018 offshore wind power had fallen off with a capacity factor of only 23%, with even poorer performance from Onshore wind power.  Wind power shows a huge degree of variability meaning it can never be regarded as consistent and dependable power source.

There is an “urban legend” that Offshore wind power has a regular capacity value of ~45%.  A level approaching less than 40% was achieved in the peak productive year of 2015 but this level has since fallen to ~23% in 2018, so even Offshore wind power is hardly productive.

The capacity values shown for the UK are the combined values since Renewable installations started in 2002 rather than the current values from 2015.  In 2018 at 16.6% overall was a particularly non-performant year for UK Weather Dependent Renewables.


Cost Comparisons

The following US  EIA website makes detailed cost comparisons in US$, avoiding the distorting effects of Government policies supporting Renewable Energy.

Click to access table_8.2.pdf

These comparative US$ values have been condensed and reduced to a common costs comparator of costs / Gigawatt for both capital and long-term costs (60 years the equivalent life of a Nuclear generating installation), on the site below.  For the sake of these comparisons  US$ and the Euro are considered to have similar purchasing power.  Thus resulting the expression of costs here for the UK in Euro billion.

The 2018 level of UK Renewable installations are shown below. A total of 33.4 Gigawatts of name plate installed provides ~5.5GW of equivalent electrical output.

screenshot 2019-01-07 at 12.12.29
It is clear that Gas-firing, at ~1€billion / Gigawatt in capital costs and about 4€billion / Gigawatt in 60 year long-term running costs, is the cheapest form of effective electricity generation.  In addition Gas-fired stations can be built relatively rapidly in about 2 years.

Using the US EIA estimated cost figures combined with the current, 2018, scale of the UK Renewables fleet, the combined overnight capital costs of UK Renewables is ~100€billion so far and that installed fleet, if maintained, will cost ~400€billion over a 60 year service life.

That level of capital investment in Gas-fired generation could provide about 90GW of generating capacity:  this is more than twice the average UK power demand and would be available 90% of the time, accounting for maintenance.

Thus the excess capital costs over the use of Gas-firing already expended on UK Renewables amount to 90+€billion with a future further commitment approaching 400€billion.  Weather Dependent Renewables in the UK are 16 – 17 times more expensive that using well established Gas-firing technologies for electricity generation.

The comparative values above do not account for the following additional costs of Weather Dependent Renewables:

  • the essential continuous availability of back-up generation to cover the times when the Renewables are non-productive
  • the non dispatchability of Weather Dependent Renewables
  • the disruption of the Grid from the fluctuating and intermittent power production from Renewables
  • the potentially large and sudden swings in power availability resulting from  including Renewables
  • the linkage of often remote generators from centres of population
  • the degradation of Renewables power production as they age


In comparison with the EU(28) as a whole the costs of UK Renewables are about 25% higher both because of the heavy commitment in the UK to costly Offshore wind power and also because the rapidly developed Solar installations over the past few years.



The late Prof David Mackay in a final interview before his untimely death in 2016 said that the concept of powering a developed country such as the UK with Weather Dependent Renewable energy was:

“an appalling delusion”.

At the time he also said:

“There’s so much delusion, it’s so dangerous for humanity that people allow themselves to have such delusions, that they are willing to not think carefully about the numbers, and the reality of the laws of physics and the reality of engineering….humanity does need to pay attention to arithmetic and the laws of physics.”

In the UK, Weather Dependent Renewables are approximately 16 – 17 times more expensive in both capital and lifetime costs when compared to the use of Gas-fired Generation technologies. 

The excess costs over using Gas-firing of the current UK generation fleet amount to some 90€billion and the long-term costs approach a further 300€billion.

If the objectives of using Weather Dependent Renewables were not confused with possibly “saving the planet” from the output of Man-made CO2, the actual cost in-effectiveness and inherent unreliability of Weather Dependent Renewables would have always ruled them out of any consideration as means of National electricity generation.


1 thought on “UK Weather Dependent Renewables performance in 2018

  1. Pingback: UK Weather Dependent Renewable Energy installations / capacity % / costs: 2017 | Principia Scientific International

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