As a part of the IEA’s Technology Collaboration Programme, the Energy Storage TCP supports the work of independent, international groups of experts working to advance the research, development, and commercialisation of energy storage technologies. We aim to enable governments and industries from around the world to conduct programmes and projects on a wide range of related technologies and issues.
Our mission is to facilitate integral research, development, implementation, and integration of energy storage technologies in order to optimise the energy efficiency of all types of energy system and promote an increasing use of renewables over fossil fuels.
Storage technologies are a core component of efficient and sustainable energy systems. Since energy storage is a cross-cutting issue, we rely on expert knowledge from many disciplines (energy supply and all end-use sectors, as well as distribution). Our high-level coordination work makes it possible to use all of this experience efficiently and benefit from the resulting synergies, develop suitable working plans and research goals. Our strategic plan therefore includes research (strategies for scientific research and development, dissemination, and market deployment), as well as coordination activities (aims and administration).
Energy Storage and the Energy Transformation
To limit global warming, the entire worldwide energy system must be decarbonised (see Climate Summit COP21 in Paris, December 2015). This calls for closed carbon cycles, the substitution of fossil energy carriers with renewable ones, and the consequent reduction of CO2 emissions from power generation. Solar and wind energy have a large and still rapidly growing additional potential for power generation, serving expanding electricity markets and new sectors. However, other energy-intensive sectors, such as heating and transportation, must also undergo considerable change to end their dependency on fossil fuels. This process, which is happening globally despite having individual characteristics in each country, is already under way, manifesting itself in an increasing use of heat pumps, electric cars, green hydrogen, and synthetic fuels. This raises the significance and market share of renewable electricity, which is subject to fluctuations in production, which in turn establish the future relevance of energy storage to provide balancing of supply and demand.
The Different Shapes of Energy Storage
Depending on the required form of energy and storage period, various technologies, such as thermal, electrical, or chemical storages, are suited and available. Choosing the right one for a specific purpose begins with the question, which form of energy is to be stored and which form is needed afterwards. Most commonly these are:
- Heat-to-Heat (thermal)
Thermal storages are used wherever energy is needed in the form of heat or cold. Common ways of differentiating them are by working principle or duration of storage.
Sensible storages employ only the heat capacity of a storage material matched to its application. They have proven their reliability in several decades of use. Latent heat storages, on the other hand, use the energy stored in a phase change. They have a high energy density and can deliver heat at a very specific temperature. Finally, thermochemical energy storages use sorption or chemical reactions. Most thermochemical storage technologies are at an early stage of development, while some, like zeolite storage, are on the market. Built correctly, they can store energy at virtually no temporal loss.
Short-term thermal storages add flexibility to energy systems and allow for a high degree of heat utilisation in residential and industrial applications. The wide variety of possible target temperatures calls for using a wide variety of technologies. Long-term thermal storages, on the other hand, are almost exclusively sensible water storages. They run only a small number of cycles per year and are mostly used for seasonal balancing and to increase system efficiency in residential applications.
All thermal storages are very easily scalable.
- Power-to-Power (electrical, electrochemical, mechanical)
Electrical energy storages have very short reaction times, work at a high roundtrip efficiency, and can deliver very high power output over a short time span. Having no moving parts, they are highly reliable. Their main application is to improve power quality, e.g. in semiconductor fabrication.
Electrochemical storages, i.e. Batteries, are already widespread and established. They are easy to scale, install, and integrate into existing systems. Their ability to buffer electricity makes them key technologies for grid stabilisation and balancing, but also for sector coupling. As an essential component of electric vehicles, their overall number is growing steadily.
Mechanical storages, such as pumped hydroelectric, stand out with their simple working mechanisms, relatively low cost, and ability to exploit pre-existing structures and local topography, like differences in elevation.
- Power-to-Fuel (chemical)
Chemical energy storage methods use electricity to produce hydrogen, synthetic fuels, or commodity chemicals like ammonia. They are used for long-term or seasonal energy storage due to their storability and high energy density. Further, they allow for surplus electricity from renewable sources to be used in industry or aviation.
To learn more about the different storage technologies that form these categories, visit our technologies page.
Energy Storage in Use
Even though international coupling points and grid interconnections help optimise the flow of energy, local energy system characteristics are still the deciding factor for storage use. One common trend throughout the very heterogeneous energy sector, however, is a significantly growing share of wind and solar power while fossil energy carriers, especially coal, are losing relevance. The resulting need to integrate larger shares of fluctuating energy forms while simultaneously reducing the number of base load power plants requires great changes in transport and distribution networks. Changes like the establishment of storage capacities, more flexibility in demand, or a combination of the two.
Innovations for Energy Storage
Resulting from these necessities, energy storage will play a more complex and important role in the future. Its value increases constantly, while it is becoming an indispensable key technology for a growing number of applications (e.g. integration of renewables, electromobility, micro grids, or decentralised autarky), managing limited grid capacities and thus creating new economic value as well as technological degrees of freedom (e.g. thermal storage for demand-side management).
The two major innovation challenges for every energy storage technology are:
- Techno-economic improvement: reduction of investment cost, increased lifetime, higher efficiency, more compact design, increased safety
- Economical-regulatory hurdles: non-discriminatory market access, a working business case/market design, regulatory matters (e.g. taxation), security of investment in uncertain markets
All of these challenges need to be tackled simultaneously, because an efficient, low carbon, sustainable, and stable energy system requires the large-scale deployment of fluctuating renewable energies and, consequently, balancing of supply and demand through energy storage.
Our Participating Countries are:
Austria, Belgium, Canada, China, Czechia, Denmark, Finland, France, Germany, Israel, Italy, Japan, South Korea, the Netherlands, Norway, Slovenia, Sweden, Switzerland, Turkey, United Kingdom, USA.
Our sponsors are:
- BVES – Bundesverband Energiespeicher Systeme e. V. (German Energy Storage Systems Association)
- University of Seville, Spain
- CIC energiGUNE, Spain
Our limited sponsors are: