Potential of heat storage for the state of Berlin

In this project, RLI scientists and project partners are analyzing the potential and demand for heat storage in Berlin. They also determine the resulting space requirements for the status quo up to the climate-neutral heating system in 2045. The experts develop measures and instruments for the development and implementation of heat storage systems in Berlin.

The role of storage in the transformation of the heating sector

Various heat storage systems play a central role in the transformation of Berlin’s heating sector. Short-term heat storage systems improve load management for the adjustment of electricity consumption and increase the efficiency of the energy system through sector coupling of heat and electricity. Long-term heat storage systems make it possible to store excess renewable energy in months with lower heating demand in order to use it during the heating period. This leads to an increase in the renewable coverage ratio in the heat supply. This is the proportion of the heating requirement that can be covered by renewable energy (or waste heat).

Use cases and storage technologies

The project team identifies relevant use cases for the use of heat storage systems and links these to suitable storage technologies. The experts also analyze the legal framework and economic parameters of the storage technologies.

Analysis and evaluation of storage systems

For their analysis, the scientists use decarbonization roadmaps from heating network operators, studies on the development of decentralized heat pumps in Berlin, basic geodata and forecasts and assumptions on the development of district heating networks. At the same time, the team identifies influencing factors and obstacles based on case studies and relevant stakeholders, such as district heating network operators, operators of small local heating networks and housing cooperatives. With the help of simulations of these case studies, the team can analyze and evaluate various heat storage systems based on technical, energy, economic and ecological parameters.

See also: https://www.berlin.de/sen/uvk/klimaschutz/waermewende/gesamtstaedtische-waermeplanung/potenzialanalysen/ermittlung-der-waermespeicherpotenziale/

Project period: January 2024 – December 2024

• Presentation of the functionality of different types of heat storage systems and identification of suitable storage technologies for the use cases in Berlin
• Recording and description of existing and planned heat storage facilities in Berlin
• Definition of relevant use cases; linking with suitable heat storage technologies.
• Development of specific case studies with the SenMVKU and relevant stakeholders
• Model creation, optimization, analysis and evaluation of the case studies in different use cases with and without storage
• Identification of storage requirements and derivation of space requirements as well as conclusions on locations
• Formulation of measures and instruments to support the expansion of heat storage facilities

The final report can be downloaded directly here: Download final report only in German.

These are the key findings:

• Heat storage as a central element of the heating transition
  Heat storage systems play a central role in Berlin’s climate-neutral heat supply. They enable the utilisation of surplus heat, relieve the electricity grid and make the energy system less dependent on fossil fuels. Heat storage systems will become more economical and therefore more relevant as fossil fuel prices rise in the future and the proportion of renewable heat increases.
• Heat storage optimises waste heat and renewable heat utilisation in the integrated grid
  With a RE and waste heat capacity of 700 MW and a heat storage capacity of up to 440 GWh, long-term heat storage could increase the proportion of waste heat and renewable heat in Berlin’s integrated grid by approx. 5 %. Correspondingly less external fuels or electricity would be required for peak loads. Short-term storage can also reduce the load on the electricity grid and support effective load management. Doubling or tripling the capacity in the interconnected grid to up to 6.6 GWh is considered sensible.
• Heat storage in neighbourhoods enables full use of renewable heat sources
  In neighbourhood networks, aquifer heat storage systems could store up to 33% of the annual heat by storing excess RE and waste heat in the summer months and releasing it during the heating period. Aquifer heat storage systems therefore help to ensure that urban heat sources such as data centres or the wastewater disposal system can be almost fully utilised. They also make neighbourhood systems more flexible and reduce the load on the electricity grid.
• Space-saving heat storage systems are essential for Berlin
  The availability of space in Berlin is limited. Above-ground heat storage systems in city centres often come up against hurdles in terms of land use planning and building regulations. The legal authorisation depends heavily on the individual case, in particular on the construction method (above or below ground) and the respective building area. Underground heat storage tanks can provide a remedy here. Underground storage tanks require a lot of space, which is often not available in urban areas. Aquifer storage systems, on the other hand, only require comparatively small areas above ground, which makes them particularly suitable for urban areas. However, there are still gaps in our knowledge about the suitability of Berlin’s underground for heat storage. The planned geothermal energy roadmap aims to significantly improve the level of knowledge. High-temperature aquifer heat storage systems are more area-efficient than ground source heat storage systems. A mix of technologies will be necessary in order to cover the heat storage requirements on a site-specific basis.
• Legal uncertainties in the authorisation process and gaps in knowledge are slowing down expansion
  Unclear authorisation procedures, a lack of knowledge about the underground and limited space make implementation difficult. Political decisions could prioritise heat storage as part of public services of general interest. High investment costs and other techno-economic aspects are also an obstacle, but are less specific to Berlin and are fundamentally related to overarching and overall systemic issues of the heat and energy transition.