Heat storage covers a very broad range of technologies and applications. It ranges from hot water boilers storing several hundreds litres of hot tap water overnight, through 10,000 m3 water vessels for peaks in district heating demand, all the way to experimental compact heat stores using thermochemical materials for lossless storage of summer's solar heat for winter usage.

Heat storage is always part of a larger system, serving to optimise the system performance or to enable the system to provide new functions. The technologies have minimal visibility, but nevertheless the effect of heat storage technologies is huge. Better heat storage can increase the solar energy produced by solar thermal systems. Advanced heat storage technologies enable the utilisation of summer solar heat for winter heating, raising the share of renewable heat in the built environment to 100%. With compact heat stores, micro cogeneration technologies (e.g. fuel cells and Stirling motors) can be operated more efficiently, following the electricity demand at every moment. In short, every device that needs heat to supply its service can be used more effectively when it is equipped with a compact and efficient heat storage technology.

At the start of PREHEAT, there was no such thing as a "heat storage community", due to the large diversity in technologies and systems, and hence the large number of companies and institutes working on heat storage technologies. Most of the companies are small to medium sized enterprises with small R&D budgets and no possibilities for long-term investments due to the lack of long-term objectives made by European and national policy makers. The development and application of heat storage technologies needs a co-ordinated and programmed approach on an international level.


The objective of PREHEAT was to provide the industry and decision makers in the EU with a reference framework to maximise the environmental, commercial and economic benefits of these heat storage technologies and to increase the attention and funding possibilities for heat storage technologies implementation.

On the long term, the aim of PREHEAT was to initiate a coherent European promotion program with a collective approach by the industry, R&D institutions and other market actors, leading to a substantially increased utilisation of renewable energy, and an increase in rational use of energy.


Heat storage technologies are supporting technologies that improve the performance of renewable energy systems (e.g. solar collectors or biomass boilers) and systems rationalising use of energy (e.g. heat pumps or micro cogeneration). The development and application of heat storage technologies needs a co-ordinated and programmed approach on an international level with long-term objectives and funding.

From the diverse and large number of companies working on heat storage technologies (mostly SME's), PREHEAT has initiated a heat storage community, and raised the awareness of the need for efficient heat storage, boosting the implementation of RES and RUE. The project has concentrated on the analysis of the decision making process and of methods of policy reinforcement, on describing present and future markets for heat storage technologies, on establishing communication with relevant decision-makers in administration and industry, and on targeted promotion heat storage solutions integrated with RES.


The results of the project are:

  • a reference framework about heat storage technologies for industry and policy makers,
  • increased awareness of the market actors in the EU-25 about opportunities for new investments in heat storage applications integrated with renewable sources of energy,
  • increased attention and funding possibilities for heat storage technologies implementation.

Target groups

The PREHEAT project has focused on the approach of key actors in the whole product life cycle to optimise the result of the project. PREHEAT's primary target groups are policy makers and industry.

The first primary target group for the PREHEAT project is policy makers. This group consists of energy policy makers on the national and European level, including industrial policy makers, national energy offices, and national and European parliaments.

Another primary target group of PREHEAT is industry. This includes industry that is directly involved in the realisation of heat stores, such as the metal construction industry, chemical industry, heating appliances, steel tank industry, heat storage industry and cold storage industry, building materials industries. However, it also includes indirectly involved industries, such as manufacturers of heat pumps, solar energy components, cogenerating heat and power units and building components.