Utilizing wind and solar energy more efficiently, cutting down on fossil fuels and providing secured capacity - this is the contribution to be made by pumped storage power plants in Germany by 2050. This is the key result of a new study of Rheinisch-Westfälische Technische Hochschule Aachen (RWTH Aachen University) about the future role of pumped storage power plants in Germany. The study, commissioned by Voith Hydro, was presented in Berlin today.

Within the context of the energy transition, the scientists of RWTH examined the role of pumped storage power plants, i. e. large power stores, for two scenarios: one for the year 2030 with a 60 percent share of renewable energies in power generation, and one for the year 2050 with a share of 80 percent.

The study shows that with a 60-percent share, about two terawatt hours of electricity can be additionally utilized, if the pump storage systems in Germany are extended to a capacity of 15 gigawatt. At the same time, up to 13 gigawatt of secured capacity from pumped storage systems would be available. As a result, the need for new power plants running with gas will be largely reduced. In the second scenario, when the share of renewable energies takes up 80 percent, the effect of pumped storage systems can be improved, because their assumed total output of 23 gigawatt by 2050 allows the following advantages: 5 terawatt hours of renewable energies will be additionally integrated into the grid. The secured capacity from pumped storage systems can rise to up to 16 gigawatt. Germany would be able to build and run fewer new gas power plants. The operation of the pumped storage systems would be profitable, and power generation costs would drop. At the same time it can be expected that there are macro-economic benefits.

"The study points out that pumped storage power plants will provide a significant back-up to the integration of renewable energies from 2030," explains Dr.-Ing. Andreas Schäfer, Chief Engineer at the Institute for Electric Plants and Energy at RWTH Aachen. Moreover, pumped storage plants would offer important systems services, especially for control reserves, but also for the provision of secured outputs. In this way, pumped storage systems can make a contribution to the success of the energy transition.

Energy suppliers already have to switch off wind or solar plants, whenever the supply of eco-friendly generated electricity is getting excessive. The reason: grids would otherwise be destabilized, and there would be a risk of power cuts. Pumped storage power plants, on the other hand, store surplus green energy temporarily and feed it back into the grid on demand at a later date.  "Pumped storage power plants are therefore multi-function power plants, which help us to lead our energy system swiftly and smoothly into the new era of energy generation without fossil carriers," says Heike Bergmann, Board Member of Voith Hydro in Germany.

"It is obvious that we need more storage capacities for the energy transition. And now we also have to create the appropriate economic conditions," says Stephan Kohler, Chairman of the Board of Deutsche Energie-Agentur (dena). "Pumped storage power plants should be given first priority, because they are the only existing industrial-scale power storage systems and, beyond that, also make many valuable contributions to the power grid. We have to adapt the framework conditions in such a way, that this added value is also adequately remunerated."

dena, in cooperation with other stakeholders, has launched the platform "Pumped storage power plants - partners of the energy transition", in order to create awareness of the high energy relevance of pumped storage power plants in an energy system with a large share of renewable energies. At the same time, dena would like to work towards the creation of suitable framework conditions in the energy sector. Voith is one of the partners of the platform. http://www.pumpspeicher.info

At present, the pumped storage power plants operating in Germany have a combined output of approximately 7 gigawatt. The expansion potential in Baden-Württemberg and Thuringia alone amounts to nearly 24 gigawatt. Numerous projects are already being planned.

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Hydropower is the largest, oldest and also most reliable form of renewable energy generation. Worldwide it makes an indispensable contribution to stable power supplies and hence to economic and social development – both in industrial countries and in emerging markets. At the same time, hydropower significantly contributes to climate-protecting energy generation. Voith has been a leading supplier of this technology since the early beginning, and continuously develops it further.