Gregor Götzl
Geological Survey of Austria (GBA),
Hydrogeology & Geothermal Energy Department

The Geological Survey of Austria is involved in various ongoing projects researching the use of geothermal energy in Austria. What role can geothermal heat play in ensuring sustainable heating in the future?
What makes geothermal energy particularly effective is its versatility: it can be used in thermal processes ranging from under 10°C (cooling) to over 150°C (generating electrical energy). However, sustainable and environmentally friendly heating makes by far the largest contribution to the energy supply. Geothermal energy has also begun to play a much more important role in large-scale seasonal heat storage in recent years.

There are several significant areas of application as far as sustainable heating is concerned:
> Air conditioning for larger buildings or renovated properties with thermal loads of over 20 kW
> Connecting up several buildings or whole sites into so-called anergy networks, in which geothermal energy – particularly geothermal probes – are used primarily as seasonal heat storage.
> Environmentally friendly cooling using geothermal energy, with the waste heat generated subsequently recovered for use in heating
> Conventional heating networks supported by geothermal energy at temperatures ranging from 50°C to 100°C in conurbations
> High-temperature geothermal energy storage systems (up to approx. 90°C) in combination with conventional heating networks (geological heat accumulators)
> Efficient CHP combined with geological heat accumulators (where there are hot springs over 100°C)
 
How can the existing resources be best used? Where do you see the greatest need for more research and development?
The use of geothermal energy has a high application potential, particularly in urban areas, as this technology takes up little space on the surface and does not generate any emissions (exhaust gases, noise or waste heat). All forms of geothermal energy can also be combined with heating and cooling networks. Therefore, there is a need for R&D to improve the integration of geothermal energy into urban heating and cooling concepts. Besides technological developments (e.g. low-carbon, space-saving drilling techniques), this includes above all the development of planning and analysis tools to be able to manage the resource of geothermal energy in urban areas in the best possible way and minimise environmental impacts. A suitable legal framework also needs to be created to accompany the research.
Further R&D is needed on the construction of geological heat accumulators and the application of petrothermal technologies (e.g. hot dry rock). The major benefit of petrothermal energy is that it is less dependent on the geological environment, particularly the presence of hot springs, and could be used to complement the traditional hydrothermal energy in the future. There is still a lack of pilot and trial systems in Austria for both high-temperature geological heat accumulators and petrothermal energy generation. It is important to set these up over the next ten years.