In order to optimise local and regional energy systems with a high percentage of renewable energy, consumption has to be made flexible. One way to introduce this flexibility on the consumer side are power-to-heat plants, which generate heat by electricity from renewable sources to use it locally straight away or store it. These storage systems help to balance the fluctuations between power generation and consumption and increase grid stability.

Pooling hot water storage systems

The Heat Water Storage Pooling project aims to group together existing heat storages of different sizes and uses (from boilers in single-family homes to large-scale storage systems for district heating) in order to create a pool which is characterized by a high total capacity and flexible characteristics. Existing storage units are upgraded and combined into one large virtual storage unit as part of the project, which is run by Forschung Burgenland GmbH together with Energie Burgenland AG and other partners.1 Wind turbines, regional heating systems and storage systems are integrated into a single system inside this virtual power plant. Automated control of the thermal storage systems allows power-to-heat operation to be shifted to times when a lot of wind power is generated.

Testing with the help of energy customers

To evaluate this approach, heat storage units of at least 30 individual customers, a district heating network and five apartment buildings are connected to the so-called Energieleitwarte (i.e., a central station responsible for scheduling and operating the different system components) and the operation of the pooled hot water storage systems is optimised. The project helps to develop and trial a pioneering concept involving economic and social aspects to enable the integrated pooling of hot water storage systems for a broad rollout.
 
PROJECT GOALS
> Minimising costs for customers and suppliers by optimising storage system operation
> Optimising grid operation by pooling heat storage vertically
> Increasing the potential for integrating multiple renewable energy sources  
> Avoiding wind turbine shutdowns
> Avoiding the need for regulating and balancing energy
 
Combining systems into a virtual storage unit harbours enormous potential for using heat storages to provide flexibility. Burgenland alone is home to several thousand small-scale thermal storage systems connected to electrical heat generation as well as several hundred units in residential buildings and the potential for up to 170 GWh in district heating per year. The concept can also be replicated in other regions, it can help to optimise the energy system and push the integration of renewable energy sources into grids and markets.
greenenergylab.at/projects/heat-water-storage-pooling/
 
¹ Project partners: Forschung Burgenland GmbH (project management), Energie Burgenland AG, 4ward Energy Research GmbH, energy & meteo systems GmbH, Pink GmbH