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There are no quick fixes to long-term energy challenges. To find solutions, governments and industry benefit from sharing resources and accelerating results. For this reason the IEA enables independent groups of experts - the Energy Technology Initiatives, or ETIs1.

Energy Storage

Heat recuperated from a waste incinerator is transferred to an industrial drying processor using a thermo-chemical storage tank.*

Waste heat, want heat

Policy context
Energy storage technologies bridge the gap between the energy at the source and the time and place that the consumer may need it. Recuperating the temperature from the ground, air, or water significantly reduces heating/cooling demand. Electrical storage combined with intermittent renewable sources has the potential to balance the electricity network. Energy storage enables policy makers and industries to reconcile energy, environmental and economic goals. However, further research will be needed to move energy storage technologies to widespread market deployment.

The objectives of the ETI focusing on thermal and electric energy storage (ECES) are to develop and demonstrate advanced thermal and electrical energy storage technologies for applications within a wide range of energy systems, and to encourage their use as standard engineering design options. Activities include case studies, demonstration plants, deployment, in situ measurements and design tools. There are currently 17 Contracting Parties and two Sponsors. 

Many of the processes in the industry sector are  energy intensive as raw materials must be heated to high temperatures. Once used, much of the heat from these processes is vented into the atmosphere as waste heat: an inefficient and costly method.

As a result, the focus of one recent ECES study, Transportation of Energy by Utilisation of Thermal Energy Storage Technology, was to examine the technical and economical feasibility of recuperating this waste heat and transporting it to other industries and district heating networks.

The objectives of the project were to develop high-capacity storage materials and high thermal power charging and discharging technologies, for transporting waste heat. Using a systems analysis approach, aspects such as the potential costs and effects, matching supply with demand, and best practice in co-ordinating activities in the field were considered.

The study concluded that recuperating waste heat is not only technically possible, it is also economically feasible for transportation using truck, train or boat. However, this depends very much on the particular conditions as determined by the energy system under investigation.

A high number of journeys between the point of supply and consumption is necessary to achieve a return on investment. Therefore industries within close proximity should be favoured. The market price for the heat at the point of consumption is also an important factor to consider. Under favorable conditions - 250 degree Celsius (°C) with 1 000 transport cycles per year - the price for heat could be competitive at EUR40/MWh.

As a result of the study, in September 2012, the first mobile sorption storage (a high-capacity, high-efficiency thermal energy storage tank)  began test operations in Germany. Further applications include recuperating waste heat from vehicles where presently 80% of fuel heating value is emitted as waste heat through exhaust. 

Photo courtesy of MVA Hamm Betreiber GmbH.

Current projects

  • Applying energy storage in ultra-low energy buildings
  • Electric energy storage: future energy storage demand
  • Material research and development for improved thermal energy storage systems
  • Surplus heat management using advanced thermal energy storage for CO2 mitigation 
  • Thermal response test for underground thermal energy storage

For more information: 


1.Information or material of the IEA Energy Technology Initiatives, or ETIs (formally organised under the auspices of an Implementing Agreement), including information or material published on this website, does not necessarily represent the views or policies of the IEA Secretariat or of the IEA’s individual Member countries. The IEA does not make any representation or warranty (express or implied) in respect of such information (including as to its completeness, accuracy or non-infringement) and shall not be held liable for any use of, or reliance on, such information.