Expanding hydropower – the example of Germany

Hydropower has been used for centuries in Germany. Often, hydropower was the start­ing point for merchants and cottage industries (mills, pumps, etc.). Starting in the mid-19th century, hydropower was used to generate electricity, and up to 2003 it was the largest source of renewable electricity in Germany. Today, hydropower provides some 20 billion kilowatt-hours of electricity per year, roughly 4 per cent of the country’s elec­tricity consumption.

At the same time, hydropower is the only renewable source of energy that has been largely exhausted in Germany; roughly 75 per cent of its potential is already exploited. The potential for new large hydro dams has already been completely used up, though current systems can generally be revamped to increase power output considerably.5 For instance, the Rheinfelden plant was modernized to increase power production more than threefold. The power increased from 26MW to 100MW, and the annual power production, which began in 2010, will grow from 185GWh to 600GWh.6

Micro hydropower units, in contrast, still have a lot of potential. The German Hydropower Association (BDW) of Munich estimates that units with an output of up to 5MW could increase the amount of electric­ity from hydropower by around 50 per cent.

Over the past 100 years, some 50,000 microhydro units have been decommis­sioned in Germany; in 1850, roughly 70,000 such units were still in operation. But often, they did not pay for themselves because the rates they received were too low, water rights were disputed or financing was hard to get for urgently needed repairs. But since the Feed-in Act of 1991, the situation is changing. From 1990 to 1999, the number of microhydro units that generate electricity increased from around 4400 to 5600.7 These new systems alone generate some 80 million kilowatt-hours of environmentally friendly electricity, roughly enough to cover the power consumed by more than 200,000 German households.

Reactivating old units is not the only way to increase the amount of energy from hydropower. Technical improvements can also be made to old water wheels and turbines.8 But generally, expanding and increasing the efficiency of hydropower units requires large upfront investments that only pay for themselves over long periods of time.

To expand hydropower further, current approval procedures, which are quite complicated, need to be simplified, and the right of use for water must be given for generous periods of time.

Hydropower potential is unevenly distrib­uted across Germany because of the country’s typology. The two southern German states of Bavaria and Baden- WQrttemberg have some 75 per cent of German hydropower potential (see Figure 7.2), while there is very little potential in the north.

Baden-

WQrttemberg

 

Bavaria

 

Total hydropower potential in Germany
ca. 25 TWh/a

 

image105

Figure 7.2 Hydropower in Germany

Source: Kaltschmitt, Wiese. Chart: triolog

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