policy recommendations

The policy recommendations developed by the expert team (not included in the brochure) are as follows:

There is broad agreement within the expert group that most of the technologies and applications discussed in the results paper are ready for implementation and realization of energy system transformation! It is now a question of the will and the removal of some barriers, especially regulatory barriers. The expert group has drawn up recommendations for action on how heat storage systems can develop their potential. These are summarised here.

Further details and background information can be found in the full document. There the recommendations for action are taken up at the appropriate points

There are various barriers to the widespread use of heat storage technologies, which should be removed:

- Many heat accumulators are technologically mature and are available for low investment costs. Here, regulatory obstacles stand in the way of an economical application. With a future-oriented framework design, subsidies and grants for individual technologies can be reduced or made superfluous.

- Innovative energy concepts for heat storage should be able to demonstrate the reliability and advantages of implementing the energy system transformation of these market-ready technologies in demonstration projects.

- In order to remove technical barriers, innovative heat storage technologies require funding on the basis of research and development programmes.

 Creating a single regulatory framework covering all energy sectors

The use of heat accumulators is - despite favourable investment costs - often not economically attractive, mainly due to the burden of taxes, levies and charges. These should only occur in the final sector of energy use and especially not in the case of conversions between sectors and in energy storage.

Adapting existing regulations in a non-discriminatory manner and with the same conditions for all energy storage facilities

In the relevant legal texts, there are exceptions for e.g. pumped storage plants or for storage solutions that only concern the electricity sector. In this area, the power-to-heat-to-power storage systems under discussion in NRW for use in coal (or gas) power plants that will be shut down in the future as a supplement or replacement are not mentioned. For heat storage systems this has the consequence that, in addition to the generally valid obstacles, there are further disadvantages in the competition between the various energy storage technologies. Here it is important to reduce discrimination and to enable energy storage facilities to compete fairly and openly with each other within the scope of the range of flexibility options.

Need for a high degree of planning security

Due to the long service life of heat storage systems - an advantage over other energy storage technologies - it is important to have predictable boundary conditions and financing concepts for longer periods of time in order to enable investments in heat storage systems. A transformation path for the transformation of energy systems that is as robust as possible, also in the perspective after 2030, improves the planning reliability of long-term investments in (large) heat storage systems.

Promotion and market launch of heat storage systems

Existing measures for favourable financing concepts and promotion aids should be expanded (e.g. NRW Bank, Kreditanstalt für Wiederaufbau) in order to help heat storage units to be used in the areas where NRW is strong. The support should not relate to individual storage units, but to storage systems. Often the costs of the actual heat storage unit play a subordinate role. Investment support should extend to all components of heat storage systems (heat accumulators, PtH technologies, re-electricity generation, and especially system integration and engineering).

In addition, the testing and further development of new storage materials (ceramics, salt, metal, etc.) should be specifically promoted. The initial demonstration should be supported by R&D projects for market entry.

Use of waste heat

In addition to the possibility of transferring electricity to the heating sector at a favourable network-oriented price in times of oversupply, there is also great potential for waste heat utilisation from industry and commerce. Here, too, heat storage systems are useful for balancing heat demand and heat generation. Where no sink for waste heat is available, technically feasible electricity generation should be encouraged by reducing taxes, levies and charges. This considerably shortens the payback period of waste heat generation and makes the use of heat storage systems more attractive for stabilizing waste heat and making the energy system more flexible.

Thinking about long-term heat storage in the future energy system

Since district heating in Germany is mainly used in densely built-up cities, there is not enough space or expansion space around CHP producers for large heat storage facilities. The construction of large heat storage facilities on the outskirts of cities involves high connection costs to the heating networks.

Denmark is often regarded as a model for the long-term storage of heat. These are mainly used there in rural areas. In rural settlement structures, heating networks are only sporadically available in Germany.

For this reason, neighbourhoods should be promoted with energy concepts that include heating networks and long-term heat storage. Long-term heat storage systems are also useful for buildings not connected to a heating network. It should be possible to integrate locally available renewable resources (solar thermal, geothermal) as well as waste heat or electricity from renewable energy sources that do not place an additional burden on the electricity grid.

Reduction of barriers in technical regulations

For the implementation of innovative heat storage systems, there are a whole series of very specific obstacles in technical regulations that stand in the way of the spread of heat storage systems.

These include substances such as glycol as a heat transfer medium, for which there are no uniform national regulations regarding water law issues. The situation is similar with questions of building law when it comes to underground structures for storage reservoirs or contradictory statements on hazardous substance limits in the Federal Immission Control Act. 

Targeted potential detection of heat and cold storage tanks

It makes sense to carry out a potential assessment for the large number of heat storage technologies and their use in different sectors and systems for coupling the sectors, which also includes the energy industry and regulatory framework, and distinguishes between the theoretical, technical and economic potential. In order to estimate the technical potential of heat storage systems, it is essential to record the temporal course of the heat source and sink, as well as the temperature levels and the heat carriers. The potential for cold storage is of particular interest, since the demand for cooling is likely to increase significantly in the future and cold storage is an ideal interface for coupling the different energy sources in cooling.