Store4HUC historical urban buildings and energy storage - pilot project Weiz Austria

In the European project Store4HUC, solutions are being developed for energy storage and renewable energies to be installed in listed buildings. Four pilot projects will be carried out in historic urban buildings in different countries. Those countries are Austria, Italy, Slovenia and Croatia.

The municipality of Weiz is the second-largest city in Eastern Styria in Austria. In the Store4HUC project there, the focus is on the integration of a heat storage unit in the Roman Catholic basilica of Weizberg, which is connected to the district heating network.

The district heating network is operated by a bio-heating power plant near the church. The bio-heating plant was founded in 1999 by 24 innovative farmers from the region. The heat supply reaches 12 customers, including the church, public buildings and several companies. The firing of the biomass boiler is based exclusively on regional biomass. The plant is currently operated without storage and without additional oil or gas boilers.

Due to the lack of a central heat storage tank, the heating plant does not run at its optimum output. As a result, the heating plant needs higher fuel consumption and higher emission values. The project aims to achieve higher energy efficiency with integrated water storage and a reduction of CO2 emissions.

The plan is to install a 38m3 water buffer tank, which will make the heat supply of the basilica more efficiently. The additional water storage tank will be complemented by a remodelling of the machine room and the control room. The extension should result in a saving of 9 % in the use of biomass. Also, network heat loss is to be reduced by 2 % as a result of the conversions.

One of the main reasons for the lack of the storage facility is the specifications of the listed site in the historical centre of Weizberg. The most challenging hurdle is compliance with the legal guidelines for maintaining the visual historic townscape. Through the Store4HUC project, solutions were found for the planned expansion of the biomass cogeneration plant.

Therefore, the following requirements and needs have to be fulfilled locally and also nationally due to the approval situation: 

  1. The implementation mostly below terrain and surface level
  2. Utilization of existing buildings to cover the extension and associated restrictions regarding the dimension of a new building
  3. Unique design for the facade and colours while complying with the requirements for weather resistance
  4. Minimally invasive interventions to protect natural conditions 

Due to the chosen innovative approach, it is possible to integrate the existing biomass cogeneration plant with the planned water buffer storage in the historical city centre. The project enables the parish church to reduce CO2 emissions and contributes to the sustainable development of the city. The project serves as a best practice example of energy efficiency and the improvement of the renewable energy system.  

For more information on sustainable urban development about historic buildings, please visit the Store4HUC website.