Discharge test at deeep geothermal site in Aspern, Vienna, Austria (source: Wien Energie via LinkedIn)
Initial discharge tests have started for the first deep geothermal project in Vienna, Austria, aiming to gather data for the design of the eventual geothermal heating plant.
The first discharge tests have now started for the “deeep,” the deep geothermal project in the Aspern district in Vienna, Austria being jointly developed by OMV and Wien Energie. This test will last approximately one week, during which temperatures, volumes, and the chemical composition of the waters will be analyzed. Such tests will be instrumental in gathering data before designing the above-ground infrastructure, including the heating plant.
Drilling for a three-well program started in December 2024 and was completed by July 2025. The wells reached a depth of approximately 3000 meters. During the discharge test, up to 3400 cubic meters of water will be pumped from depth to the surface and into reservoirs. This will be followed by another test during the 2025/2026 winter season, where both extraction and reinjection will be done simultaneously for the first time. The results from both tests are expected by the spring of 2026.
Brine sample from geothermal well in Aspern, Vienna, Austria (source: Wien Energie via LinkedIn)
“With the findings from the extraction tests, we can finalize the planning of the above-ground plant – i.e., those plant components required for transferring heat from the formation water to the district heating network. This will be followed by the construction of the plant. Vienna’s first deep geothermal plant will then serve as our blueprint for further expansion: By 2040, we aim to generate sustainable district heating for up to 200,000 Viennese households with several plants,” said Wien Energie Managing Directors Michael Strebl and Karl Gruber.
In total, OMV and Wien Energie aim to develop deep geothermal plants with a capacity of approximately 200 megawatts to meet this demand. The partners plan to implement up to seven deep geothermal plants in Vienna. Several wells and plant sites are planned to be constructed in parallel, giving the benefit of more efficient resource use. The exact implementation schedule and the performance of these additional plants depend on the findings from the pilot plant in Aspern.
“All Viennese residents should be able to heat their homes in a climate-friendly way by 2040. District heating is a key technology for this. With heat from 3,000 meters underground, we are making district heating sustainable step by step ,” explains Ulli Sima, City Councilor for Urban Development, Mobility and Vienna Public Utilities.
“With the deep production tests, we are now letting the subsurface speak for itself. For OMV, geothermal energy is a key element of the responsible transformation to a low-carbon company. We are committed to concrete measures to reduce CO? emissions and are thus making an active contribution to a sustainable and reliable energy supply. Thanks to our decades of experience in the oil and gas business, we have the necessary expertise in geosciences and drilling technology to make geothermal energy available as an energy source ,” added Berislav Gašo, Executive Vice President Energy and member of the OMV Executive Board.
Source: Wien Energie via OTS