Archive for August, 2017

So what happened to the science?

August 11, 2017

There is an excellent guest comment today at the WUWT blog by John Ridgway. There are no graphs, but essentially very sound reflections on the social impacts on a science that gets politicized, as climate science has become.

Let me just cite a few of  what I think are the best remarks in this very readable article:

  1. I suspect the problem is that climatologists are making predictions that cannot be readily falsified through appropriate experimentation
  2. The lack of falsifiability sets the scene for the achievement of consensus by other means, resulting in a certitude that cannot be taken at face value
  3. it is a logical non sequitur to suggest that a model that performs well for the purposes of hindsight will necessarily be reliable for the purposes of making predictions.
  4. With the Hockey Stick to hand, the IPCC no longer needed to bury the uncertainty in the body of its reports, since the graph proved that the uncertainty simply didn’t exist…it is difficult to avoid the conclusion that the data had been mercilessly tortured for a confession
  5. the consensus, rather than being a result of minds being changed during debate and inquiry, instead emerges following a form of sociological natural selection
  6. in climatology the situation is worsened by a politically motivated denial of uncertainties and a lack of commitment towards openness and the reproducibility of results

Please read this comment with an open mind!

PS: here for your information how the Mann’s hockey-stick reconstruction differs from that of Loehle (source):


Wind and Solar: Intermittency, backup and storage (part 2)

August 9, 2017

In the first part of this comment I wrote that the study of F. Wagner on the 100% renewables aim of Germany’s Energiewende showed that this would need a massive blowup of the electrical power structure (about 4 times more capacity than the needed load has to be installed), and a non avoidable production of surplus electricity, which might become more a liability than an asset.
In this second part I will discuss some points of the second study by Linnemann & Vallana “Windenergie in Deutschland und Europa, Teil 1” published in the June 2017 issue of the VGB Powertech Journal (link1 to paper, link2 to additional slides). This interesting study only looks at wind power, insists on what is needed to guarantee reliability, and what has been achieved during the tremendous increase in German wind power from 2010 to 2016.

  1. Big increase in installed capacity, none in minimum.

The following slide shows the big increase in installed capacity during one decade: from approx. 27 GW to 50 GW:

Two facts are sobering:

a. the maximum produced power (during a short annual time-period) decreases from 81% to 68%, in spite of the nearly double installed capacity, and the more modern wind turbines (see blue curves).

b. the minimum power delivered remains constant at less than 1% of the installed capacity. In other words the guaranteed power available at every moment of the year is less than 1% of the installed capacity.

If one makes a statistical analysis, the distribution of the delivered power is very asymmetric and far from normal :

This histogram gives the percentage part of a certain delivered power during 2016 where the mean u is about 8.7 GW. The sum of all relative frequencies left to that mean ( i.e. the blue area left to the vertical u) is high, and corresponds to a 60% probability that the delivered power is low.

2. The capacity factor of the installed wind turbines.

Despite the doubling in installed capacity, the change to more modern and powerful wind turbines, and the increase in offshore wind parks (which in 2016 delivered 12 TWh out of a total of 77 TWh), the overall capacity factor remains depressingly low, and also low when compared to other European countries:

The large variations are essentially due to changing weather patterns: 2010 was a very low wind year for most of Europe. The long-time mean of the CF from 1990 to 2016 did increase by no more than 1% for the 2010-2016 period.

Compared to other European countries Germany’s wind turbines do a disappointing job (note that CF% = [Ausnutzung/8760]*100); the CF always lies close to the lower range.

3. How much backup power?

The VGB report is very clear: you need 100% of the installed  renewable wind capacity as backup. The cause is that the minimum guaranteed power (“Gesicherte Leistung”) is close to zero; the next table shows that this is the case for practically all countries, even those like Ireland or Denmark which are geographically privileged:

As the best windy places are mostly used, a bettering could theoretically be reached by modernization (“re-powering”) and smoothing by including all European producers in one big grid. The real data suggest that neither of these solutions is very effective; low wind areas often extend over a large part of Europe (wind is often strongly correlated over much of Europe).

4. Conclusion

The minimum delivered power during the 2010-2016 period is about 0.15 GW, which represents the displacing of conventional (fossil/nuclear) producers by the newly installed wind turbines. In other words, the doubling to 50 GW installed wind capacity has made only a ridicule low amount of 0.15 GW conventional electricity generators superfluous!

Wind and Solar: Intermittency, storage and backup (part 1).

August 7, 2017

A couple of recent papers/studies make a thorough analysis of the German Energiewende and the new problems caused by relying more and more on intermittent producers. The first paper is by Friedrich Wagner from the Max-Planck Institut für Plasmaphysik. Titled “Surplus from and storage of electricity generated by intermittent sources” it was published in December 2016 in the European Physical Journal Plus (link). The second is part 1 of a two part study published by VGB Powertech in June 2017. The authors are Thomas Linnemann and Guido S. Vallana, and the title is “Windenergie in Deutschland. Teil 1: Entwicklungen in Deutschland seit dem Jahr 2010” (link) .The link points to the original version in German, but an English translation will be available soon.

I wrote a comment on this last paper titled “Vom Winde verweht“, adding some reflections concerning the situation in Luxembourg; this has been published in the Saturday 5th August 2017 edition of the Luxemburger Wort, Luxembourg’s largest newspaper.

  1. A switch from demand orientated to supply driven.

One of the most important aspects in the rush to decarbonize the electricity sector is that a fundamental change is planned to enable the functioning of intermittent suppliers like wind and solar. The traditional electricity market is demand driven: the client has a certain maximum intensity hardwired in his counter or inbox (say 32 A or 64 A per phase, usually there are 3 phases); he can rely on this maximum which will be available at all time (but possibly at a different price according to a predefined peak or low demand period per day); the electricity supplier must do his best that the power asked for will be delivered at the correct voltage and frequency.
The new planned situation will see a swapping of the roles: the supplier decides what electrical energy he will deliver and at what price, and the consumer must accept. Smart meters allow very fine-grained changes of the tariff, which can be modified for very short time-segments; the maximum power can be throttled down if needed. All this is called DSM (demand side management), and practically robs the consumer of its freedom of  lifestyle or consumption pattern. All this because the extremely variable iRES (intermittent Renewable Energy Sources) can not guaranty a previously defined standard base-load. This supply driven “market” may recall to the older of us memories of the life in the former east-European communist states (like the DDR), where complicated 5 year state plans ruled the economy; it seems like an irony that such a life-style will be hyped as progressive by the iRES lobbyists.

2.  Unavoidable surplus and huge backup

F. Wagner’s paper gives some very interesting numbers, concerning an electricity market based on wind and solar alone. He assumes that fuels from biomass will be used for aviation, heavy machinery and big lorry transport, so biomass is not included among the future zero-carbon electricity market. Neither is hydroelectricity, which has practically reached a limit in Germany. He assumes that the future electricity consumption will be 500 TWh per year, which is a rather conservative (low) number if one thinks of the political push for electrical cars. A first conclusion is that in the wind/solar mix, solar PV electricity must not exceed about 20-25%, so there will be no equal sharing between wind and solar. The next figure (fig.2 of report added text-boxes) shows how this scenario, if it had been applied, would have worked out in 2012:

To guarantee supply, a huge backup infrastructure of 131 TWh must be installed (which corresponds to 73 GW installed capacity), and on top a yearly 131 TWh surplus energy will be unavoidable. The calculation show that when iRES sources contribute less than 25%, no surplus will be generated. In the 100% scenario, the unavoidable and strongly variable surplus which will quickly become a liability as there will be no consumer available to pay for it (note that negative price periods are becoming more and more frequent at the EEX exchange); this means that onshore wind turbines must be shutdown every year for a total period of about one month!

Speaking of surplus, the first answer of iRES advocates is electricity storage (in batteries, hydro or through chemical transformations). Wagner analysis covers short time day-storage solutions and long-time seasonal storage, which both will be needed. In winter, surplus is strong both during day- and nighttime, so a one day storage will not be enough. In spring, a daily storage solution would show a capacity factor (=efficiency) of 3%, which is ridiculously low. A seasonal storage solution which would avoid any backup infrastructure would demand an enormous  capacity of at least 100 GW. Nothing similar does exist, and no technological miracle solution for such a storage is in the pipe-line.

The conclusions of F. Wagner’s report:

  • a 100% iRES electricity production must install a capacity 4 times greater than the demand
  • if storage capacity will be delivered by pumped water storage, it must be increased by at least 70 times
  • the integral capacity factor of the iRES system will be 18%, and a backup system of about 89% of peak load must be installed
  • to nominally replace 20 GW nuclear power, 100 GW iRES power will be needed
  • an extremely oversized power supply system must be created
  • the Energiewende can not reach its coal of CO2 avoidance (“there is a clear conflict between political goal and applied method…overproduction by iRES may not be the right way to go”)


to be followed by part 2 which discusses the PWG paper