The unreliability of Weather Dependent Renewable Energy in Germany, the UK and France.

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Almost half of the Name Plate value of Power generation in Germany, the UK and France in 2019 was Weather Dependent Renewables, Wind (Onshore and Offshore) and on Grid Solar PV.   However those installations contributed less than on fifth of the power output. Being unsynchronised and their times of  production was poorly coordinated with demand, so that power output was often effectively worthless or indeed damaging to Grid stability,   

In addition the mandated “Renewables Obligation” meant that those vagaries could only be supported by dispatchable power from conventional sources, mainly Gas-firing, Nuclear and an amount of Coal / Lignite.  By European and Government policy these high quality, controllable and dispatchable resources were often forced to work inefficiently and thus non-profitably to maintain Grid frequency and consistency.

At current levels of penetration by Weather Dependent Renewables, European electricity Grids are becoming more and more unstable and at risk.  The inevitable results will be supply failures across Europe on an ever increasing scale.



The combined context

More than 55% of Weather Dependent Renewable Energy, (WDR), installations in the EU(28) are accounted for by three European Nations with markedly differing approaches to electricity generation:

  • Germany  WDR ~36% of EU(28):   the most massive Global commitment to Weather Dependent Renewables via its “Energiewende” policy
  • The United Kingdom  WDR ~11% of EU(28):  very substantial commitment to Weather Dependent Renewables and a world leader in Offshore generation
  • France  WDR ~9% of EU(28):   75%+ dependent on Nuclear generation

Combined these three Nations are characterised by:

  • together they encompass ~41% of the EU(28) population
  • together they amount to ~27% of the EU(28) land area
  • they span a wide variety of climates from the North of Scotland to the South of France:  59°N – 42°N and widely across Europe from the Atlantic coast to the East of Germany in continental Europe, across a distance North – South of some 2000kms and 1500 kms East – West.
  • these Nation account for ~56% of all the 2019 Weather Dependent Renewables in the EU(28)
  • their Weather Dependent Renewables combined account for ~47% of their installed total power generation but those Renewables only fulfil at maximum ~19% of the power demand



Hourly dataset over the year December 2018 – November 2019

This post presents graphics from a combined hourly Megawatt dataset for the three Nations over the period from December 2018 to November 2019.  All power output graphics are set to the same gross scale for direct comparisons.  Percentage graphics are set on the basis of the proportion of hourly combined generation.

Germany as a result of its long-standing Energiewende policy has now installed more than one third of the total Weather Dependent Renewables installation in the EU(28).  For further comparative details of the development of Weather Dependent Renewable generation in other European nations see:

The three National data sets are also combined for the 2018-2019 period.  Productivity / Capacity percentage is the performance measure for generation technologies, it consists of the actual Power output / Name Plate power rating.  The datasets include hourly data for the following generation technologies:

  • nuclear:  with no CO2 emissions output, productivity potential 90%, base load power, not flexibly dispatchable
  • coal:  hard coal with high CO2 production for energy generated, productivity potential 90%, dispatchable to meet demand
  • lignite:  brown coal, with very high CO2 production for energy generated, only used in Germany, productivity potential 90%, dispatchable to meet demand
  • natural gas:  the fossil fuel with the least CO2 production for energy generated, (less than half that of Coal for equivalent power output).  In the USA the transition from Coal to Natural Gas for electricity generation has achieved the greatest reduction of CO2 emissions worldwide, productivity potential 90%, easily dispatchable to meet demand
  • biomass:  in the UK primarily imported wood chips from clear felling native forest in the Eastern USA and/or other waste, as this fuel requires drying, pelletisation and transatlantic transport this fuel has a very high CO2 production for energy generated,.  The productivity potential is up to 90% and is dispatchable to meet demand

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  • hydro-pumped:  combined data for hydro electric generation and pumped storage plants.  The productivity potential is up to 90% and is dispatchable to meet demand but availability can be limited by low rainfall
  • Wind Onshore:  the original Gridwatch UK 2019 data set makes no differentiation between Onshore and Offshore generation, but an estimate is made for the UK here using the proportion of Offshore / Onshore wind production for 2019 by the Renewable Energy Foundation.  In the EU 2019 Onshore reported productivity was ~23%
  • Wind Offshore:  this data set provides the Offshore data for Germany and estimates are made for the UK Offshore installation.  In the EU 2019 reported Offshore productivity was ~35%.  France has no significant offshore generation
  • Solar PV:  grid scale photovoltaics – 2019.  In the EU 2019 reported productivity productivity was ~12% lower in cloudy northern Nations.

In addition an assessment is made of net transfers to and from each Nation.

It is important to note that:

  • these data sets count the full productivity of various generation technologies, including Weather Dependent Renewables.  The results are thus generous assessments of the value of the power produced by Renewables.  They do not account for the timing of that power production and thus of the usefulness of the power Weather Dependent Renewables may produce at any one moment in time.
  • in addition these data sets do not account for the difficulty in coping with the wide variability and intermittency of the power output by Weather Dependent Renewables within a Nation’s supply Grid, which is tasked to provide dependable and consistent power for that Nation.  The mandated insistence on the use of power from Renewables in preference to “base load power”, whenever it may be available also means that those more valuable sources of consistent power generation technologies may be chronically underused much of the time, as they are forced to continually compensate for the vagaries of weather incurred by the intermittency and variability of power production by Renewables.




The Unreliability and Intermittency of Weather Dependence

Wind farm promoters assert that the Wind is “always blowing somewhere”.  The following graphics show the percentage of generation that occurred in Germany, the UK and France over a 7 day period in January 2019, a period of high power  demand.  It is clear that in all three locations Weather Dependent Renewables were only able to provide less than 20% of the required output and on several days they produced virtually no power at all.

The Renewables power output failure was coordinated across all three Nations.  This interruption was long enough not to be able to be covered by any battery back-up.

Screenshot 2020-04-02 at 15.05.40.pngThe combined results show the coordination of low Weather Dependent Renewables production over the period.Screenshot 2020-03-31 at 15.11.35.png

In contrast the graphic below shows production over an 18 day period of excess wind power in Germany.  Wind power can ramp up very rapidly for example on 27/2/2020 from over from 10% to 70% as a storm hit widely across a country.  Often Wind power can be seen to reach 70% of power production but even with high production there can also sudden, precipitous fall-offs as shown here, dropping from ~70% down to ~30% in just a few hours.  

In addition the regularly intermittent but highly variable Solar input only complicates the problems of grid management to enable an essential consistent power supply.

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This Grid management problem induced by dependence on Renewables is well illustrated below where in summer months from May – September Wind Power rarely exceeds a 20% contribution and for extended periods it remains below 10% across the three Nations.  The average contribution over the summer period was at level of ~12%.  The problem is further exacerbated by the Solar power contribution varying daily from up to a 30% contribution to nil over each 24 hour period.

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There is some co-ordination between the Solar power production and the fall-off of Wind production in summer.  However this cannot compensate for the short term problems for the Grid that sudden changes in weather can impose, nor those that diurnal Solar production imposes on the grid:  the world turns.

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Combined Weather Dependent Renewables in Germany, the UK and France

Graphic presentations for the three Nations in combination follows.

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The crucial importance of Nuclear generation becomes clear here.  It makes the German decision to eliminate its Nuclear in a few years from now only truly emotional grounds after the Fukushima accident look monumentally ill-advised.  Similarly the French decision to cut back its effective Nuclear fleet to only about 50% of its generation, replacing the shortfall with Weather Dependent Renewables is equally foolhardy not only for France but also for the future stability of the overall European and UK power supply, often dependent on reliable Nuclear power supply from France.

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As far as CO2 emissions are concerned in 2019 still about a third of generation relied CO2 emitting fuels.  Germany is still highly reliant on Coal, Lignite and some Biomass, resulting the German CO2 emissions still being the highest in Europe in spite of its longstanding Energiewende policy.  The continuation of that policy with the attempted closure of Coal and Lignite generation as well their Nuclear fleet will endanger power supplies Throughout Germany.

The 1990s move to Gas-firing as opposed to Coal in the UK has helped reduce its indigenous CO2 emissions to well below the European average.

French CO2 emissions are, uniquely for a developed Nation, below the Global average but as they reduce their Nuclear commitment and intend to replace them with Renewables its CO2 emissions are likely to grow simply from the need for dispatchable back-up power to compensate for the vagaries of the weather impacting on Renewables.

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The performance of contribution of all nominally “Green” generation technologies including Weather Dependent Renewables in the three Nations is shown below.   Biomass and traditional Hydro electric generation make a consistent contribution of useful dispatchable power.  Even though the “detrimental” CO2 emission and biodiversity characteristics of the use of Biomass is conveniently ignored by politicians in their pursuit of “Green” goals.  The potential for Hydro electricity is wholly dependent on a Nation’s topography and only really contributes in France and Germany.

More important in this graphic is the enormous variability of Weather Dependent generation, which by mandate now has to be accommodated by National power grids.  With a continuing “Green” ambition across Europe to eliminate the use of both fossil fuels and Nuclear power this Grid management problem can only deteriorate leading to inevitable damaging cuts in power supply.

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