Electricity generation from hydropower in Germany

Author: Dr. Klaus Hassmann, Energy Technology Cluster (as of June 2017)

History

Water power, especially run-of-river power plants, is one of the oldest inventions in the generation of electric power. In Bad Reichenhall, the first German run-of-river power plant was commissioned in 1880. In the USA, the first large-scale power plant for the public supply of alternating current with an electrical output of 78 MW went into operation in 1895.

Current situation

Today, installed capacities worldwide range from a few kW to many GW; the Three Gorges Power Plant in China, for example, has an output of 22.4 GW.

Types

In a run-of-river power plant (LWK), in principle, the water level in the inflow and outflow remains the same; however, high and low water situations can cause deviations. The storage water type (SPK) is more flexible in its operation; the water can be collected in the inflow up to a certain level and later be fed to the turbine. In this mode of operation, the responsible authorities take care that during the damming phase at the lower reaches, the lack of water does not unduly threaten the habitat of the people there.

Pumped storage power plants (PSPs) consist of a lower and an upper reservoir connected by a penstock system; in times of cheap electricity, water is pumped up; a natural water supply to the upper reservoir reduces pumping; in times of high electricity prices, the kinetic energy of the stored water is used to generate electricity via the height difference between the upper and lower reservoirs. Thus, this type of storage (as well as the SPK) fulfills the important task of compensating for a shortfall or surplus of electricity supply in the face of increasingly fluctuating electricity generation in Germany due to sun and wind. The current max. storage capacity of a day storage facility is 38 GWh in Germany (low mountain range).

Economics

In the investment costs of all types of hydroelectric power plants, the structural part (steel and concrete) clearly outweighs the machine part. However, the operating and maintenance costs are low; large storage water and pumped storage - plants require ample land; extensive construction work is necessary For hydropower, feed-in priority applies on the electricity exchange. Nevertheless.....the energy transition new construction stop also applies to hydropower under the current energy transition framework - new construction would not be in the money under the current framework. It would also be rejected by a large number of the people affected for reasons of landscape protection. Opponents of pumped storage also raise fears of being threatened by the large masses of water in the upper reservoir. Supplementary and renewal measures on all types of power plants to increase output are, however, possible.

Power stations are also out of the money on the electricity exchange under the current rules. In the discussion about security of supply, however, PSC should be used much more intensively. Thanks to their so-called black start capability, pumped storage power plants can be used to start up other power plants that cannot be black started, such as coal-fired power plants, in the event of large-scale power outages.

Technology

The most common turbine types are the Kaplan, Francis and Pelton turbines. The Kaplan turbine, with its characteristics of large volume flow at low head and efficiency of over 90%, is particularly suitable for run-of-river power plants, whether with or without storage of the water inflow. The Pelton turbine, on the other hand, embodies the opposite: low volumetric flow at high head; with an efficiency of less than 90%, it is particularly suitable for PSCs. The Francis turbine lies between Kaplan and Pelton in its characteristics; Francis is thus more universally applicable. For PSK, one reckons with an average efficiency around 75%, for other types of hydropower plants up to 90%.

Key figures

In the following tables, key figures of hydropower in Germany, such as the distribution of installed capacity among the federal states, the age of the plants as well as other key figures for the years 2014 and 2016 are summarized. This overview (source: power plant lists of the Federal Network Agency) is shown to illustrate the importance of hydropower for the energy transition and also to update it in the coming years.

Running water and storage water (in operation) Power plant capacity in Germany, Distribution among the federal states

Storage water 235 MW (6%) 1608 MW < 10 MW unit capacity The oldest power plant went into operation in 1905. Largest unit capacity: 146 MW Rhine power plant Iffezheim in BW Run-of-river and storage water contributed 4.3% to the total installed capacity of renewables in D in 2014.

No new plants ≥ 10 MW in the 2 years from 2012; No decommissioning of plants Power increase of 6% through efficiency measures on existing KW Storage water 290 MW (7%) 1766 MW < 10 MW unit capacity *) Bavaria **) Baden Württemberg  ***) Rhineland Palatinate   ****) North Rhine Westphalia   *****) Plants abroad feeding into the German grid

Pumped storage (in operation) Power plant capacity in Germany, Distribution by Federal States

The oldest power plant went into operation in 1926. Largest unit capacity: 1052 MW Goldisthal in Thuringia Pumped storage contributed 7% of the total installed capacity of renewables in D in 2014.

From 2024 to 2016 no decommissioning of plants; also no commissioning

*) Baden Württemberg **) Thuringia  ***) Saxony   ****) Hesse   *****) Plants abroad feeding into the German grid

Key figures electricity generation in Germany (source BMWI) Gross electricity generation of hydropower (run-of-river, storage water, pumped storage with natural inflow)

In2012, hydropower plants with a combined cumulative capacity of about 990 GW were installed worldwide; they produced approx. 3700 TWh of electricity. Compared to this, the capacity share in D is about 1%, and that of electricity generation is about 0.6%. Hydroelectric power is used continuously; weather-related river levels cause the annual fluctuations shown in the tables. The decreasing share of electricity generation by renewables is due to the strong increase of wind and solar.

Conclusion

From the author's point of view - he worked in hydropower for quite a few years during his professional career at a large power plant manufacturer - hydropower is a flexible, robust, emission-free technology that has proven itself over a century. In the right places, whether built decentrally with small capacity or large in the high double-digit MW range, run-of-river power plants are an indispensable component in the German power supply. Their appearance is adapted to the landscape. At the moment, there is a lack of incentives for investments in conversion measures, especially of the older power plants; old technologies/components would have to be replaced by modern ones. A corresponding capacity market regulation would be helpful.