Study: Storage systems can halve heat generation costs in 2030

21.03.2025

Source: E & M powernews

Nuremberg-based regional supplier N-Ergie has commissioned an investigation into which storage technologies are particularly suitable for regional heat supply.

2-zone storage, geothermal basin heat, geothermal probe heat, rock, aquifer heat, ice storage - there is no shortage of technologies for storing heat. But which ones are primarily suitable for regional supply? And what role do space requirements, costs and temperature ranges play? These questions were the subject of two scientific studies commissioned by the Nuremberg-based energy supplier N-Ergie.

The first study, which was carried out at the Friedrich-Alexander University Erlangen-Nuremberg (FAU), sheds light on technologies that can compensate for fluctuations between summer and winter months or at least effectively bridge dark doldrums lasting one to two weeks.

According to the scientists from the Chair of Energy Process Engineering, there are sufficient market-ready technologies available for storage on a GWh scale. The technical maturity of chemical storage systems and latent heat storage systems is not yet sufficient.

As far as heat from direct electricity generation is concerned, they refer to large-scale storage systems. "For the various options for combining electricity-based heat generation and storage, large storage systems are worthwhile due to the high electricity costs and the particularly high savings potential, especially for storing heat from direct electricity generation and for storing low-temperature heat," the study states.

It goes on to say that storing heat from a heat pump only delivers significant savings for "exclusively electricity-based heat supply if the customer's heat consumption does not have to be covered by considerably more expensive direct electricity generation while the storage tank is being charged".

Maximum savings achieved with 400 to 800 hours

For the year 2030, the authors of the study expect the heat generation costs to be halved by storage systems. Based on an average wholesale price of around 137 euros/MWh in 2030, the scientists calculate average heat prices of around 32 to 62 euros/MWh for heat generation using only heat pumps and up to 242 euros/MWh for exclusive generation via direct electricity generation. According to one result, large storage systems halved the production costs with a storage capacity of 400 to 800 hours. "Even larger storage facilities do not offer any significant savings potential."

Grid costs are a central point in the considerations. "Direct electricity generation in particular would currently be subject to high grid charges due to the presumably low full load hours. This is at odds with the potentially grid-friendly operation of controllable loads such as direct electric heating systems," write the university researchers. A revision of the grid fees in the future would be obvious.

Advantages of contracting

From an operational point of view, they consider contracting models to be advantageous. Lower flow temperatures in the heating network allow higher heat pump efficiencies and reduce heat losses. "Contracting models also address the problem of the large amount of space required for heat storage," they emphasize. There are also synergy effects for grid operators in the short-term storage of peak loads, particularly from PV electricity production.

For the regional supplier N-Ergie, the FAU scientists conclude that heat storage for periods of around one month with a storage capacity of 150 GWh in the supply area is economically feasible with the current plans of the transformation plan with low-temperature storage systems.

The second study based on this comes from the Nuremberg Institute of Technology. In it, the authors model "cost effects depending on storage capacity and production costs". Detached from individual model parameters, they come to the succinct conclusion: "It is recommended to leverage the potential that storage expansion offers."

N-Energie currently operates a heat storage facility with 2-zone technology in Nuremberg-Sandreuth. The hot water storage tank is 70 meters high and has a capacity of 33,000 cubic meters. The heat capacity is around 1.5 million kWh.

The study is available to download free of charge: Storing heat for regional heat supply

Author: Manfred Fischer