The mission of Energy Conservation and Energy Storage (ES) is to facilitate integral research, development, implementation and integration of energy-storage technologies to optimise the energy efficiency of all kinds of energy system and to enable the increasing use of renewable energy instead of fossil fuels.

Storage technologies are a central component in energy-efficient systems. Since energy storage is a cross-cutting issue, expert knowledge of many disciplines (energy supply and all end-use sectors, as well as distribution) must be taken into account. To use this widespread experience efficiently and gain benefits from the resulting synergies, high-level coordination is needed to develop suitable working plans and research goals. ES is responsible for fulfilling this important task. ES’ strategic plan therefore includes research activities (strategies for scientific research and development, dissemination and market deployment), as well as co-ordination activities (aims and administration).

Energy storage and the energy transformation

To meet the GHG emission reduction targets as well as the 1.5-2 °C aim, a decarbonisation of the global energy system is required (see Climate Summit COP21 in Paris, December 2015). This implies the substitution of fossil energy carriers by low carbon energy and closed carbon cycles, which means less CO2 from fossil fuel power plants and a higher share of renewable generation. Renewable energy from solar and wind shows a high additional potential for electricity generation. But, the electricity sector only accounts for 25% of the final energy demand. Therefore, also considerable changes in the other energy intensive sectors such as heating and transportation are required.

By using heat pumps, electric cars or synthetic fuels based on green hydrogen (power-to-fuels), renewable electricity will gain more and more importance and will contribute to the decarbonisation of the heating and transportation sector as well. This global development with its individual characteristics in each country will determine the future relevance of energy storage.

Three shapes of energy storage

By enabling the temporary balancing of supply and demand energy storage has always been an important part of the energy system. Depending on the form of energy which needs to be balanced and the required storage period, different types of energy storages such as thermal, electrical, material or virtual storages can be used. While material and especially thermal systems have an intrinsic storage capacity and with that are able to absorb short-term fluctuations itself, electrical systems are highly depending on perfect balancing.

• Thermal storages (e.g. hot water) are used when the final energy to be stored is heat. Due to their high efficiency and comparatively low investment cost they can be used in various applications ranging from balancing high volatile load peaks (power-to-heat) to decentralised island solutions or even in industrial environments (heat integration).
• Electrical energy storages (e.g. pumped hydro or batteries) have experienced a very dynamic development which is especially due to mobile applications as for example electromobility. Compared to thermal storage systems, electrical storages are more cost intensive and less efficient. They store electrical energy which makes them in return to the key technology for grid stabilisation and balancing.
• Material storage systems (e.g. gas storage) are mostly used for long-term or seasonal storage and to guarantee security of supply. Virtual storages are controllable loads which can be switched on or off depending on the actual demand.

Energy Storage in our energy system

Depending on the specific characteristics of the respective national energy system, the required type and capacity of storage varies. Although the electricity flow can be optimised by interconnection of networks and the international coupling points, still the national or rather regional energy systems are decisive. The differences in status quo as well as in past developments are significant. There are countries with a high share of nuclear power (e.g. France), coal fired power plants (e.g. Poland), hydro power (e.g. Norway), gas power plants (e.g. the Netherlands) or wind and solar power (e.g. Germany).

Even though the development in the energy sector is very heterogeneous a common trend can be recognised. Overall, wind and solar power show significantly growing capacities whereas the share of fossil energies, especially lignite and hard coal is declining. The integration of fluctuating forms of energy combined with a decline in base load power plants requires large structural changes in transport and distribution networks. This requires solutions like the development of storage capacities and/or flexibility in demand or combination of those two elements.

New innovations for energy storage

As a result the future role of energy storage will be more complex and more important than today. The value of storage increases. In a growing number of applications energy storage is an indispensable key technology (e.g. electro mobility, micro grids, decentralised autarky or integration of renewables) or rather a key enabling technology which increases value creation and allows for technological degrees of freedom (e.g. thermal storage for Demand Side Management).

The two major innovation challenges for energy storage are:

• Techno-economic improvement: reduction of investment costs, longer lifetime, higher efficiency, compact design, safety
• Economical-regulatory hurdles: non-discriminatory market access (level playing field), business cases/market design, regulatory hurdles (e.g. taxation), security of investment in uncertain market development

Both challenges need to be tackled simultaneously. Because: an efficient, low carbon, sustainable and stable energy system requires the large deployment of renewable (fluctuating) energies and with that a balancing of supply and demand by energy storage is crucial.

Participating countries in TCP ES are:

Austria, Belgium, Canada, China, Czech Republic, Denmark, Finland, France, Germany, Israel, Italy, Japan, South-Korea, Netherlands, Norway, Slovenia, Sweden, Switzerland, Turkey, United Kingdom, USA.

TCP ES (limited) sponsors are:

• BVES – Bundesverband Energiespeicher e. V. (German Energy Storage Association)
• University of Seville, Spain
• CIC energiGUNE, Spain
• University of Valladolid, Spain