Energy storage systems – current status and outlook. Summary

Energy supply is facing a number of new challenges. The increasing liberalisation and globalisation of the energy markets not only sets new framework conditions, but also places new demands on the energy supply systems of the future. Central to this is the maintenance of security of supply with electrical energy in the face of increasing shares of fluctuating energy sources as well as changed procurement conditions for fossil raw materials. The prevention of further climate change and environmental pollution caused by energy supply also play an important role. Today, energy storage systems are an integral part of our energy supply system. Nevertheless, their role - outside the technical level - is hardly perceived. Against this background, the TAB report provides an overview of the current technical status of available energy storage systems and innovative storage concepts in both the stationary and mobile sectors. Energy storage systems play a key role in supply systems by making it possible or easier to match energy supply to demand that varies over time. Especially for the "volatile" energy forms of electricity and heat, there are only a few economically attractive technologies for storing large amounts of energy (e.g. pumped-storage hydropower plants). In supply systems with a high proportion of supply-dependent energy generation (e.g. wind power), energy storage can make a decisive contribution to ensuring a reliable and sustainable energy supply in the future. Subject and objective of the study Against this background - at the suggestion of the Committee for Education, Research and Technology Assessment - work on this subject area was begun in spring 2006 as a monitoring study. The aim of the study is to provide a comprehensive overview of the current status and perspectives of current and future possibilities of energy storage in application and research. The project ran within the framework of the TAB monitoring programme "Sustainable Energy Supply". Due to the high importance of the field for the energy industry and energy policy, a broad thematic approach was taken. The areas of electricity, heating (cooling) and fuels were considered together in order to sound out recognisable synergies and/or competitions between these fields. The investigations focus on areas with a high relevance for the energy industry. In addition to the new requirements for energy storage in the context of a sustainable energy supply, a structured general overview of current and foreseeable future possibilities for energy storage is given - more or less to show the range of available technical possibilities and development options. In addition, selected areas of application (grid support with high shares of renewable energies, power generation in the sun belt, storage in vehicles) are presented in their special features with regard to the storage of energy - also with a view to more advanced storage concepts. Finally, key international research priorities or aspects that appear relevant in connection with energy storage - for selected countries and regions (D, EU, USA, JP, KP) - are listed and the need for research is addressed