Specific Energy Production II – Wind and Solar PV

In one of my previous posts I took a closer look at the specific energy production of both nuclear and hydroelectric energy. We saw that there are significant differences between the two.

In the recent past other energy sources have continuously gained ground against them. In particular, wind and solar PV are considered to be production modes of the future, and maybe one day they may be the backbone of our energy-hungry society. However, for the time being, we are still far from this point. One of the reasons is that both of these renewable energy sources do not provide the necessary stability which is cruciall for running the power grid of a post-modern information society.

Now let us look into the details. First we consider wind energy which has seen breathtaking growth rates in terms of installed capacity. However, installed capacity is not the last word when is comes to the actual performance of a particular production mode. Fig. 1 shows the average figures for wind energy for the period 1996 to 2010.

Fig. 1  Sspecific energy production in MWh/MW inststalled for some selected countries.

Fig. 1 Sspecific energy production in MWh/MW installed for some selected countries.

Germany, one of the countries with the largest installed capacity, is doing significantly worse than the other countries shown in the picture. Overall we observe that  the specific production figures are well below the ones we calculated for hydroelectric energy (Specific Energy Production – Nuclear and Hydro).

Fig. 2 provides the same data for some countries which recently have done a lot of effort to promote the use of solar PV. Again, Germany is the performing worse than its competitors which in this case does not come as a surprise since sunshine hours are much more abundant in Spain and Italy. The data represent average values for the period 1990 – 2010.

Fig. 2  Specific energy production for solar PV

Fig. 2 Specific energy production for solar PV

Solar PV is no match for wind in terms of specific output. To produce the same amount of energy in MWh one has to install a much larger capacity of solar PV than wind mills, since the former ones have an average specific output corresponding to only 54% of wind energy plants.

Similarly, the specific output of wind mills is equivalent to roughly 58% of the one for hydroelectric plants. Quite astonishingly, a similar relationship exists between hydro and nuclear with the specific output of hydro corresponding to about 50% of the one for nuclear plants.

In a nutshell, in order to obtain the same production figures as nuclear power installations one needs to install almost seven times as much capacity of solar PV and more then three times as much capacity of wind generating power.