One year ago Germany decided to quit producing nuclear energy by 2022. Since nuclear power plants are a central pillar the German energy mix, contributing some 22.5% to the entire electricity output in 2010, this means that until 2022 the equivalent of 140.6 TWh (2010) has to be replaced by other sources. This is a minimum estimate ignoring increase in consumption.
Already at this moment Germany begins to face the consequences of last year’s decision. As nuclear plants are successively being phased out, more strain is put on other sources, in particular renewables. In addition, the power grid is experiencing severe tensions as more controllable sources of energy are being replaced by less controllable (and predictable) ones. Especially the latter is a constant, or rather growing source of trouble.
One the one hand, it’s a clear goal of German policy to increase the share of renewables substantially. On the other hand, it seems implausible to be able to replace the entire nuclear bloc by wind and solar capacities only. Thus, it appears inevitable to commission a number of conventional, i.e. thermal power plants which are supposed to act as a backup for the fluctuating input from e.g. wind farms.
In my view, it is pretty obvious that wind will be the main source of renewable energy in the future, considerably outnumbering all other renewable sources taken together.
In 2010 the total capacity of German wind farms amounted to some 27190 MW which produced some 36.5 TWh. Taking into account the average specific output of wind farms as calculated in one of our previous postings we may estimate the extra capacity needed in order to fill the gap. Then we could show that the average output of wind power installations amounts to some 1600 MWh annually per MW of installed capacity.
Having these figures at hand we may easily estimate how much extra wind capacity is needed in order to replace nuclear in its entirety. Thus if wind power is supposed to be the only substitute (which is certainly an oversimplified approach) it would mean that Germany needed almost 88000 MW of additional wind power by 2022, thus an extra three times as much as was installed up till 2010. This in turn would mean that the country needed more than 115000 MW in wind turbines by the time the last nuclear power station is decommissioned.
Between the year 2000 and 2010 an average of 2000 MW was commissioned annually, in total some 20000 MW of wind power. Extrapolating this trend to 2022 implies that some 24000 MW of new capacity could be added to the grid until D-day. However, what is needed is almost four times as much. Thus the annual growth rate should be close to 7800 MW. Even if we assume that wind will only replace half of the nuclear output, a growth rate of about 4000 MW annually would be necessary, i.e. twice as much as has been the case during the boom period 2000-2010.
The figure below shows two different scenarios for Germany´s wind power capacity. The business-as-usual scenario (BAU) is based on the assumption that wind capacity will grow at a rate of 1900 MW per year, which is equivalent to the increase in 2010. The Target scenario on the other hand assumes an annual growth of 7800 MW which would theoretically be sufficient to replace Germany´s entire nuclear production as seen in 2010.
Given that there is considerable resistance among the population against onshore wind farms, it is indeed hard to see how this can be achieved. In addition, as subsidies for renewable energies are becoming a serious burden for consumers, they are likely to be reduced in the future. This in turn may jeopardize further investment in wind power, and thus even the more conservative BAU scenario may, in fact, be too optimistic. As a consequence, other energy sources are desperately needed if Germany wants to maintain her standard of living. We will come back on this issue in another posting.