Graz is making constant efforts to increase the share of renewable energy in the city’s district heating system. So the project ‘HELIOS’ in Graz with its 2 000 m² solar plant has been put into operation in September 2017. The thermal energy is fed into the district heating grid of Graz.
‘HELIOS’ has a 2 000 m² solar field which will be expanded to 10 000 m² at its final completion. The expected capacity at the moment is about 2,5 GWh. The plant is situated on a closed residual waste disposal site. For this reason, all solar pipelines are laid aboveground in order to be prepared for underground movements. An unpressurized aboveground storage tank holding 2 500 m³ offers the possibility of absorbing thermal power peaks. A landfill gas CHP unit with a capacity of about 120 kW (electrical) and 170 kW (thermal) is also part of the project. The electrical output is used for self-sufficiency and to run a Power-to-Heat unit. The plant is operated by ‘Energie Graz’. ‘HELIOS’ has received funding from the local state of Styria (approx. 1,17 Mio. €) and from the state of Austria, ‘K.L.I.E.N.’ (approx. 0,45 Mio €).