Archive for December, 2012

BNA Monitorbericht “Energie der Zukunft”

December 26, 2012

The German Bundesnetzagentur has published a first report on German energy policy (see start page here). The official report strictly follows the mandatory politically correct line, and even if it is quite interesting to read, brings not much critical and original thoughts. Much better is an additional report written by various experts, who are clearly more critical and point to shaky extrapolations in the main report. But still better is a huge Excel file (“Anhang zum ersten Monitor Bericht“) with a treasure of real data. I ploughed through this impressive documents and here are some comments based on these data.

1.  What type of power plants are planned and in construction?


This table shows that in 2011 a total of 5.4+13.1+12 =30.5 GW of fossil plants were either in construction or planned, to be compared to only 4.8 GW of renewable plants (exclusively wind)! This clearly shows that Germany, despite all the hurrah surrounding PV and wind, goes for increased fossil electrical power to compensate the shutdown of its nuclear plants (see my previous comment here).

2.  What is the efficiency of renewables for reducing the fossil part?


This graph shows the fossil generated electricity (in TWh from 2005 to 2011) versus that produced by renewables: the trend-line has a slope of – 0.38, what means that 1 TWh renewables do replace only 0.38 TWh fossil generated electricity. So the “fossil avoidance efficiency” of renewables in the electricity production is only 38%, far from 100% as usually suggested by the media and politics.

Remark (added 27 Dec 2012):

One could object that simply plotting the total of fossil energy use against the renewables total is not correct, as the shutdown of the nuclear facilities had to be compensated by increased used of fossil fuels and/or increased imports. For a quick check, I subtracted the downfall of 32.5 TWh from nuclear during 2011 from the fossils total. This gives the following situation:



The displacement efficiency of the renewables increases to 0.83 or 83%.
Reality probably lies between the 2 extremes of 38 and 83 %.

(end of added remark)

3. How has the overall efficiency in energy usage changed from 2007 to 2011 ?

One of the mantras of the green movements is that most problems can be solved by using energy more efficiently. Well, everybody agrees with the goal of increasing efficiency, but real data show that this holy grail is not in easy reach. The next 2 plots show the evolution of efficiency (measured by the “Bruttowertschöpfungszahl”, i.e. the fraction in created money to used energy) of the industry sector and that of the GHD (= “Gewerbe, Handel, Dienstleistungen” ~ commerce + services). A more efficient energy usage produces more money with less GJ, so gives a higher number:



The situations are clearly opposite: whereas the industry sector has worsened, the service and commerce sector made a better job. These graphs show that increasing efficiency by a huge amount over long periods is very difficult, and not something that flows in naturally!

4. What are the capacity factors of wind and solar ?

One of the most often avoided question is how reliable are wind and solar in delivering? What fraction of the name-plate energy is really delivered during a year? The Germans usually speak of “Volllaststunden” =hypothetical  fraction of yearly hours where the plant delivers its maximum power. The capacity factor CF is simply the Volllaststuden/8760  (*100 if result is given in %).

The next table shows both the Volllaststunden and the mean CF in % in the bottom Line:


The red columns correspond respectively to nuclear, brown coal (lignite) and coal plants, the green columns to wind and solar plants. The BNA says that the solar numbers should be augmented by ~20% because so much new capacity is installed during a year, and the Volllaststunden are computed on the December situation. So let us generously add 1.5 % to solar, which gives the sobering results for the capacity factors in percent:

nuclear = 82%   lignite = 79%  coal = 50%  and wind = 17%  solar = 8.5%

As usual, nuclear is by a huge factor the best non-fossil fuel dependent method to produce reliably electrical power!
The capacity factor for wind is really disturbing, and a new report by Prof. Gordon Hughes shows that the CF’s of wind turbines rapidly worsen with age.

The next figure gives the numbers in graphical  form:


Whatever one’s position regarding nuclear power, the abyss separating wind and solar capacities from those of nuclear plants is enormous. The German wisdom in laying down their performing nuclear plants after the Fukushima event remains extremely questionable!