A research team from 麻豆官网 (LUH) and the Institute for Solar Energy Research in Hamelin (ISFH) has shown that the efficient use of electrolysers and battery storage systems has a decisive influence on the costs of the energy transition.
This is because adapting to the fluctuating supply of wind and solar energy is a significant challenge. When there is a great deal of wind and sun, there is an oversupply of power. At other times there is too little wind and sun, and sometimes even so-called 鈥渄ark doldrums鈥�, which are the simultaneous absence of wind and sunshine. So what do we do when the wind is stronger or the sun shines brighter than the demand at that time requires? Some of the excess electricity can be stored in batteries or transformed into hydrogen. These technologies allow for the power to be made available again when it is needed. And hydrogen can also be used outside the electricity system - for example, in industry.
The research team at LUH and ISFH has developed a model for optimising the German energy system and identifying the contribution that electrolysers and battery storage systems make to the success of the energy-system transformation. This makes it possible to demonstrate potential cost savings and how otherwise unused electricity can be better utilised.
In the optimised scenario suggested by the study, electrolysers are used to produce green hydrogen primarily in northern Germany, where ample renewable electricity is available from wind turbines. The electrolysers are always in operation at those times when the available electricity exceeds the current demand. In contrast, the scenario sees battery storage systems distributed across Germany, with a concentration in the south of the country, where more electricity from photovoltaic systems is available than in the north.
鈥淥ur study shows that in 2050 approximately 35 per cent of the electricity from renewable energies first needs to be stored or transformed into hydrogen in order to be used efficiently,鈥� explains Alexander Mahner, the study鈥檚 lead author. 鈥淚f we don鈥檛 do this to a sufficient extent, the overall costs of the energy transition could increase by up to 60 billion euros because we need more imports.鈥� The delayed or overly limited expansion of hydrogen facilities and storage systems would not only increase the cost of the changeover but would also make it more difficult for Germany to achieve its climate goals.
The two technologies, battery storage systems and electrolysers, work differently. Electrolysers transform electricity into green hydrogen, which is then used primarily in industry. The conversion of electricity into hydrogen makes it possible to save the energy over a longer period of time. Battery storage systems, on the other hand, are used to balance energy supply and demand in the short term. They are primarily utilised to balance solar energy supply between day and night and are not suitable for longer-term storage.
The optimal outfitting of the energy system with storage systems would mean we would see fewer wind turbines that are inactive even though a strong wind is blowing. At the moment this sometimes has to be the case to prevent the overburdening of the system when there is too much power in grid.
The study delivers valuable basic principles for decision-makers in politics and business who are responsible for managing the transition to a climate-friendly energy system. It is important that the sluggish expansion of electrolysers and electricity storage systems be tackled in a considered and purposeful way, rather than haphazardly. The research project was carried out with financial support from EWE AG.
The complete study, titled 鈥淟ess curtailment via increased flexibility in the energy system 鈥� The cost of the energy transition also depends on how excess electricity can be used by electrolysers and battery storage systems鈥�, is available (in German) here:
Note to editors:
For further information, please contact Alexander Mahner, M.Sc., Institute of Solid State Physics, Solar Energy Section (tel. +49 511 762 19758, email: mahner@solar.uni-hannover.de).
