Executive summary of the
“The Role of Energy Storage in Future Energy Systems”
Workshop, September 30. – October 2. 2009, Bad Tölz, Germany

The Implementing Agreement “Energy Conservation through Energy Storage”, ECES, has organized a workshop on the future role of energy storage.

Scope of the Workshop

Energy storages are central components of many energy systems. Looking at the “Energy technology Perspective 2008”, the reduction of CO2 emissions until 2050 can only be achieved by introducing a lot more renewable energies and substantially increasing the overall energy efficiency. Both measures are tightly connected to the development of innovative storage technologies. Energy storage is explicitly mentioned in several of the “Energy Technology Roadmaps” (e.g. Wind Energy, Solar Heating and Domestic Hot water, Electric and Plug-in Vehicles and Solar Concentrated Power). In addition to that, at the last workshop of the Experts Group on Science for Energy (EGSE) energy storage was defined as one of the key energy technology challenges.

Actvities on energy storage are ongoing in a number of Implementing Agreements. The fields of applications are covering a wide range. However some of the basic problems in the development of efficient storage systems are similar. This big variety of technologies and applications of energy storage creates a need for better coordination of the different activities. Like other “Coordination Groups” for buildings (BCG) or electricity grids, a group on energy storage could help to identify possible synergies for the future and to initiate coordinated actions in the future.


The organisation of the workshop was supported by the Committee for Energy Research & Technologies CERT, the End-Use Working Party EUWP and the Renewable Energy Working Party REWP. Peter Cunz, Chair of CERT, Hermann Halozan, Chair of EUWP and Andreas Indinger, Vice-Chair of REWP were participating the meeting.

The following Implementing Agreements sent their representative to the workshop:

  • Solar Heating and Cooling (SHC)
  • Buildings and Community Systems (ECBCS)
  • Energy Conservation through Energy Storage (ECES)
  • Electricity Networks Analysis, R&D (ENARD)
  • Heat Pump Programme
  • High Temperature Superconductors (HTS)
  • Hydrogen (HIA)
  • Solar Power and Chemical Energy Systems (SolarPACES)
  • Advanced Fuel Cells (AFC)

The IA on District Heating and cooling (DHC) send a presentation on their actual activities on energy storage. One representative of a German energy utility (e.on) was participating.

Presentations by the Participants

Peter Cunz (CERT) opened the workshop by emphasizing the importance of energy storage for various developments in energy technologies. He said on the other hand that the general topic of energy storage is quite complex and therefore difficult to be presented to decision makers. He asked the participants to create a common understanding for the future role of energy storage and a better visibility for the whole field.

Hermann Halozan (EUWP) presented the coordinating effort of the EUWP, which are already established (Building, transportation and electricity coordination groups). He described the need for collaboration in the field of energy storage, since the storage is always just part of an energy system. He made clear that 60% of the CO2 reduction potential can be identified in the end-use sector by improving energy efficiency, which is strongly connected to energy storage.

Andreas Indinger (REWP) talked about the impact of the economic/financial crisis and who will finance innovation. These questions are most relevant for the decision makers in the aim to have about 50 % Renewable Energies in the middle of the 21st century, which is also indicated by results if IEA long term sustainable energy scenarios. Energy storage is, together with the topic of “smart grids” crucial for the integration of Renewable Energies. A further discussion on the improvement of today storage technologies is focussing on the development of new storage materials.

SHC works on low temperature thermal energy storages for heating and cooling applications. Topics are short term buffer storage, industrial process heat, but main interest is on seasonal storage. The importance of energy storage was underlined (“Solar thermal stands and falls with the storage capacity”). Furthermore the benefit of a stable research program on energy storage (at least 10 years) was pointed out as well as the need for demonstration projects, building codes and heat directives.

The Hydrogen Implementing Agreement gave an overview about the present HIA tasks and the activities in task22 on hydrogen storage. Some examples for innovative materials were given and a comparison of hydrogen storage / fuel cells in cars to Li-ion batteries and fossil fuels was shown. An outlook on the technical R&D-Demands was given. Up to now a large number of different hydrogen storage materials has been discovered with very different advantages and disadvantages making them suitable for different types of applications. Engineering activities concerning prototype tank design and construction increase in this task and will very probably lead to a new separated task. In order to compare this kind of energy storage to other technologies the whole chain of energy transformation, from hydrogen production over storage to the fuel cell system including the heat management, has to be taken into account for different envisioned applications. Aspects like storage capacity, hydrogen release and uptake kinetics as well as working temperatures and pressures, security and cost are of importance.

DHC presented one example of a successful demonstration plant of a thermal energy storage system connected to a solar thermal installation and a local district heating net in Canada, carried out in cooperation with ECES. Beyond the successful demonstration, the specific costs have been too high. Over a period of 40 years the life-cycle costs have been 0.13$/kWh, respectively 0.17$/kWh for 25 years.

SolarPaces pointed out that there is no “one fits all “-solution for thermal energy storage in combination with concentrated solar power plants. Each system has to be adapted to the special requirements. Even when the specific cost has not decreased as expected, the market has increased substantially. Following moderate scenarios, the number of installed systems in the 1000 MWh range will be 480 in 2015 and 1360 in 2020. The actual investment costs of 50-100 €/kWh have to be reduced to 50 €/kWh in maximum.

ENARD mentioned “recognition by the ExCo of the current potential role for storage in electrical power systems”. On the other hand, concerning storages in applications ENARD raised the question whether the storage integration in application is possible at all within the current market and technology structures.
Furthermore, it was pointed out, that there is a “clear commitment to storage” in the US, leading to the aim of about 1000MW advanced electrical storage in 2018. The next steps will go in the direction of demonstration, new business models, regulatory changes as well as technological development.
HTS laid the main focus on Flywheels and Superconducting Magnetic Energy Storage (SMES) as energy storage systems. In the presentation, the progress concerning energy density and also safety was pointed out. Results from demonstration projects in the US, Japan and Europe have been shown. Even if superconductivity is presently considered as a niche, the need for further R&D-activities was pointed out. The funding for R&D in Japan, the US and Corea increases and the development in Europe is being driven by the industry. Further applications for high temperature superconducting energy storages are for example electric vehicles and trains.

ETSAP presented their general methodology. Their aim is to characterise 80-90 energy technology clusters, which in fact include different types of energy storages. The output is a brief summary similar to the IEA-essentials. Furthermore, a short description of the tool itself was given.
ECBCS was represented by a German expert. Only a short description of the current activities was given. The presentation showed the strong relationship between energy efficient buildings and storage integration.

HPP also emphasized the meaning of energy storage for an efficient heat pump operation. Using heat pumps for heating and cooling as well, the coefficient of performance might be increased with an additional storage. Because of the strong link between both technologies, further cooperation including joint ExCo-meetings are of particular interest.

AFC gave a brief overview of the actual R&D-results. At the moment there is no strong demand for storage integration, as a thermal management plays a minor role. This will become more relevant in the future.

ECES gave in addition to the introducing presentation about the potential of energy storages in the different end-use sectors a brief overview concerning the aims and the ongoing activities. Even when there was a strong focus on thermal storage systems, ECES decided one year ago to continue the activities concerning electrical storages. This is due to the fact, that the total efficiency of the whole system (represented from the choice of the system boundaries) determines the best storage solutions. Therefore, electrical and thermal systems are taken into account in future.

Summary of Discussions

All participants agreed on the need of substantial innovations for storage technologies and that future cooperation and coordination in the field of energy storages might be very fruitful. It was pointed out, that many Implementing Agreements may involve storage technologies, but probably not as efficient as possible. Furthermore, a cooperation among the IAs would increase the visibility of energy storage and therefore its importance. It was common sense, that beyond technical aspects the storage “solutions need to fulfil ecological and economical demands as well as social acceptance and sustainability” as Hermann Halozan pointed out. Questions of limitation and availability of resources for storage materials had been identified as important issue.
To reach this, a coordinated output from the related Implementing Agreements is necessary.
The fact, that representatives from eleven Implementing Agreements as well as from the CERT, the EUWP, the REWP, EGSE and the IEA Secretariat joined this workshop has been regarded as a successful kick-off to the future activities.
To emphasize the meaning of energy storage as a central component in energy efficient systems, ECES will contribute to the road map on energy efficient buildings in the ETP 2010.
Beyond this it was suggested to organize every two years a “Future Energy Storage Forum”, similar to the “Future Building Forum”.
Furthermore, a “State of the art”-report and joined summer schools from different Implementing Agreements have also been judged as very helpful to increase the visibility of energy storage and to initiate collaborations on expert’s level.

Next steps

  • On the annex level, a joint annex between ENARD and ECES was proposed from ECES. This proposal have also been discussed at the ENARD workshop in October.
  • ECES offered to the IEA Secretariat to coordinate the input to the roadmap on energy efficient buildings in the ETP 2010. The IEA Secretariat has asked for assistance in organizing altogether two workshops on energy storages in the building sector. The first workshop will take place on December, 8th. ECES assists in inviting experts on the different (thermal) storage systems. Furthermore ECES will prepare a draft paper as first basis for the workshop.
  • In February 2010 the results from the ETP 2010 workshop in December 09 will be discussed with the other building related experts (e.g. heat pumps, solar heating and cooling) at the BCG meeting.
  • Discussion with IEA Secretariat on planned and possible publications addressing storage issues (ECES, EUWP, REWP)
  • Beyond this contribution to the ETP, ECES will start a cooperation with ETSAP. ECES will review the technology briefs and will ask the storage experts to contribute to technology briefs on different energy storage technologies.
  • The installation of a “Forum on Energy Storage” has been decided, this has also been presented from the Chair of the EUWP at the CERT meeting.

Astrid Wille
Chair of ECES

Andreas Hauer
Secretary of ECES