Hybrid Grids Demo - City as Energy Sponge

Power and district heating grids are connected to act as functional power storage. Producers and consumers get recommendations as to when feed-in and use make sense and are cost-efficient.

Hartberg develops an energy sponge system for power, heating and cooling. The energy flows are to be optimized in real time in regard to network and energy carrier. (c)Stadtwerke Hartberg

The vision behind the project “Hybrid Grids Demo Hartberg” is clear: the city acts as energy sponge that regulates the energy supply in the city and its catchment area.  This method shall allow low cost energy storage and pass energy on as demand rises. To this end the municipal energy system is transformed into a functional energy storage that can hold large amounts of energy. The energy supply and energy usage systems are to be made more flexible by means of a passive energy carrier and inter-network distribution network operation that does not actively interfere with the highly sensitive network controls. 

The technological centerpiece is an optimizer. It is installed in parallel to the existing control infrastructure. The optimizer provides recommendations & advice to producers and users, e.g. it will inform users not to heat up puffer storage in times of demand peaks and recommend postponing heating up the puffers at times when there is excess district heat available and energy can be procured at lower costs.  It is then up to the user to decide whether or not to heed the advice. In a further stage of expansion automated processes are to be incorporated.

The city of Hartberg lends itself to participating in such a pilot project for rather pragmatic reasons: unbundling directives in a liberalized market would complicate testing such a hybrid network approach. 

Another decisive issue in the project is that this pilot takes into consideration many different load profiles. There are different types of users. For example, A private household shows a different load profile over the course of time than a restaurant where a lot of cooking is done around lunch time. A manufacturing company’s profile differs from that of a bakery. Various energy producing facilities feature different production profiles. Here, too, the key to success lies in using synergies and flexibility to increase the overall system’s efficiency.

This project is funded by the Climate and Energy fund and is carried out within the framework of the “Smart Cities Demo”- program.

Funding agencies, research & cooperation partners

Funding agency

Project team and project manager

Project manager

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