Underground Sun Storage 2030 - Start

Underground Sun Storage: World's first geological hydrogen storage facility goes into operation

04/27/2023 | Press release

Rubensdorf, 27 April 2023

Large-volume storage of hydrogen enables energy transition while maintaining security of supply.

  • With “Underground Sun Storage“, the world‘s first hydrogen storage facility in an underground porous reservoir, RAG Austria AG – Renewables and Gas – and its project partners are setting new international standards.
  • In this unique cross-sector demonstration facility, solar energy is converted into green hydrogen by water electrolysis and stored in pure form in an underground natural gas reservoir in Gampern, Upper Austria.
  • The scale of the storage corresponds to the summer surplus of about 1,000 photovoltaic systems on family homes. In summer, this surplus energy is stored and in winter the green energy can be provided again in the form of electricity and heat.

Two years after the start of the project, the underground sun storage facility and the storage facility goes in operation in April 2023 in the presence of Governor Thomas Stelzer, representatives of the BMK, BMF and Climate and Energy Fund. Markus Mitteregger, CEO of RAG Austria: “In our pioneering demonstration facility, we will bring 4.2 million kWh (4.2 GWh) of summer electricity in the form of hydrogen into the winter and thus secure the supply of renewable energies. We map the entire value chain and focus on a perfect interplay of generation, conversion, storage, and future utilization paths of green hydrogen.” In the future, this geological storage facility will be able to convert the solar power surplus of around 1,000 family homes from the summer into hydrogen and store it seasonally.

“In Gampern in Upper Austria we are demonstrating what is possible and necessary to ensure a secure supply of green energy throughout the year and thus enable the energy transition.”, Mitteregger emphasizes.

Securing the energy future – making renewables supply-secure

The pioneering work of RAG Austria and its partners is of utmost importance for companies, political decision-makers, and authorities for the future transformation of energy systems. The results of the “Underground Sun Storage“ demonstration project will make it possible to reposition gas storage facilities with their enormous storage volumes in the energy system of the future, also as hydrogen and green power storage facilities. Austria in particular has great potential with its ideal geological structures and existing modern storage capacities. This will make it possible to decouple the generation of renewable energy and its short-term consumption and to enable year-round security of supply.

Hydrogen makes sun and wind storable

Hydrogen is the essential component for achieving climate targets and increasing the security of energy supply. Hydrogen can be produced without CO2 emissions and can be used cleanly and flexibly in all sectors – whether for applications in industry, heat and power generation, or mobility. But the decisive factor is its large-scale storage and transportability in the existing almost invisible gas infrastructure.

"A rapid ramp-up of hydrogen is essential. It is not enough to push the expansion of renewable energies. The solar and wind power of the summer months must be made storable and thus brought into the winter, when wind is not constant, and sun and water do not supply enough energy to meet the increased demand. Experts predict a seasonal energy transfer of 10 TWh per year by 2030 in Austria alone. "Underground Sun Storage" is the first step in this direction, which must be followed by others," says Mitteregger, explaining the need to make renewable energies storable in the form of hydrogen in order to ensure a secure supply of energy.

Austrian Federal Minister of Finance / Mining Magnus Brunner: "Climate protection is one of the central tasks of our generation. Our goals are ambitious: 100% renewable electricity in and from Austria by 2030 and climate neutrality in Austria by 2040 – still ten years ahead of the EU. To achieve these climate targets, we need investment, innovation, and cooperation. In any case, we must not concentrate on a few technologies, but must remain open to new technologies. With the world's first geological hydrogen storage facility, RAG is focusing precisely on this technological openness, which we so urgently need: The stored green hydrogen makes an important contribution to year-round supply security – at the same time it replaces fossil natural gas and thus reduces our dependence. A win-win situation for climate and location!"

Minister of Climate Action Leonore Gewessler emphasizes: "Underground Sun Storage demonstrates how the secure supply of clean, affordable energy will be possible in the future. RAG Austria AG has managed setting international standards and showing how the conversion to a climate-neutral Austria can succeed. If we can convert a storage facility for fossil gas into a storage facility for green hydrogen, this is a step into the green energy future. With this knowledge, Austria can play at the top of the global competition."

"For Upper Austria as the No. 1 economic and industrial area, hydrogen is a decisive key factor in making the location even more future-oriented. Numerous domestic companies are already leading research into the storage, use and supply of hydrogen. With our Hydrogen Offensive 2030, we are investing in this future field and further expanding our pioneering position. This storage facility is therefore an important impulse for the clean energy future of our country," emphasizes Governor Thomas Stelzer.

Climate and Energy Fund – Bernd Vogl: "With Underground Sun Storage, RAG Austria AG once again proves that an outstanding team from science and industry can deliver trend-setting results for a future 100% renewable energy system with rapid climate impact. It is remarkable with which commitment and excellence innovative projects are developed here and convince our jury every time anew. We are already looking forward to further steps towards broad implementation and further initiatives."

Lighthouse project with renowned partners

Under the leadership of RAG Austria as initiator and technology leader, hydrogen will be produced in the customized demonstration facility by 2025 and stored underground in a gas reservoir in order to be used in the region in the future as a material or as an energy source, or also directly via hydrogen power plants to serve the security of supply with electricity and heat.

Together with the project partners – Axiom Angewandte Prozesstechnik GmbH, Energie AG Oberösterreich, Energy Institute at JKU Linz (EI-JKU), EVN AG, HyCentA Research GmbH, K1-MET GmbH, Vienna University of Technology, University of Natural Resources and Life Sciences, Verbund AG, Verein WIVA P&G and voestalpine Stahl GmbH interdisciplinary technical-scientific investigations will be carried out under real conditions at a small former natural gas reservoir for the energy future.

These investigations will be complemented by the development of suitable processing technologies, the modelling of future energy scenarios and techno-economic analyses. These investigations will be complemented by the development of suitable process.

These include, for example:

  • Hydrogen as a substitute for fossil natural gas
  • Direct use in energy-intensive industries
  • Processing requirements and technology
  • Utilization possibilities of hydrogen with high purity

The worldwide unique project “Underground Sun Storage“ is part of the energy showcase region WIVA P&G and an important step for the development of a secure hydrogen economy. The use of underground gas storage for hydrogen storage is also included in the Long-Term Strategy 2050 – Austria according to Regulation (EU) 2018/1999 of the European Parliament and of the Council on the Governance System for the Energy Union and Climate Change. The project is funded under the Energy Research Program of the Climate and Energy Fund.


Project Partners

  • RAG Austria AG
  • Axiom Angewandte Prozesstechnik GmbH
  • Energie AG Oberösterreich
  • Energieinstitut an der Johannes Kepler Universität Linz
  • EVN AG
  • HyCentA Research GmbH
  • K1-MET GmbH
  • Technische Universität Wien
  • Universität für Bodenkultur
  • Verein WIVA P & G – Wasserstoffinitiative Vorzeigeregion Austria Power & Gas
  • voestalpine Stahl GmbH


Press contact

Stefan Pestl
Head of Corporate Communications
Schwarzenbergplatz 16
1015 Vienna
Tel.: +43 (0) 50724 5460


RAG Austria AG

For more than ten years, RAG Austria AG has been working with hydrogen as an energy source in order to store renewable energy on a large scale and seasonally. The company develops leading edge energy technologies related to green gas and hydrogen that partner renewables. This enables RAG to play a vital role in attaining Austria’s ambitious climate goals, and in the sustainable stewardship of the country’s raw material and energy supplies. Our goal is to provide our customers with safe, efficient, environmentally friendly and affordable energy and gas storage services – sustainably and responsibly.

The business focus is market driven storage, conversion and conditioning of energy in gaseous forms. The company has gas storage capacity of about 6.3bn cubic metres (cu m) of natural gas, or about 6% of total capacity in the EU. A large part of RAG’s gas fields have already been converted into storage facilities, which can rapidly discharge stored energy in large quantities on-demand. In this way RAG is delivering on its vision of “sustainable energy mining”, and decisively reinforcing security of supply in Austria and Central Europe.


Axiom – Angewandte Prozesstechnik GmbH

Axiom Angewandte Prozesstechnik GmbH is a family-owned, medium-sized, technology-oriented company with a focus on separation technologies, in particular on the application of membranes for various gas and liquid separation processes. Axiom has developed and successfully commercialized numerous new separation processes such as biogas upgrading, hydrogen recovery and EOR systems.

Company activities cover the entire process implementation: Basic engineering, process integration, detail engineering, construction, commissioning and service. In addition, Axiom dedicates a significant part of its work to applied research and development with the aim of offering optimized separation processes for the modern and sustainable energy industry.


Energie AG Oberösterreich

Energie AG Oberösterreich is a modern and efficient energy and services group. As a provider of electricity, gas, heat, water as well as waste management and ICT services, Energie AG stands for the highest quality and reliability of our products, processes and services. As a competent and competition-oriented company, customers are offered a fair price/performance ratio and regional availability, which ensures a cooperative relationship with customers, employees, suppliers and the public.


Energy Institute at the Johannes Kepler University Linz

As interdisciplinary research institution the Energy Institute at JKU Linz (EI-JKU) has comprehensive competence in the fields of energy law, energy economics and energy technology can look back on many years of intensive research in the field of power-to-gas. During this time the Energy Institute has built up extensive expertise in techno-economic and ecological assessment as well as legal analysis in connection with the development of power-to-gas value chains. This know-how is rounded off with the competence to carry out qualitative environmental analysis to develop recommendations for action for successful technology implementation.



EVN is a leading, international, listed energy and environmental services company based in Lower Austria, the largest Austrian province.

In its home market, EVN offers electricity, gas, heat, drinking water supply and wastewater disposal as well as thermal waste utilization "from a single source" on the basis of state-of-the-art infrastructure. The product range also includes the operation of cable TV and telecommunications networks as well as the provision of various energy services for private and business customers and municipalities.

Around 4.8 million customers relied on the secure supply of energy and environmental products and services from EVN in the 2019/20 financial year.


HyCentA Research GmbH

For more than 15 years, HyCentA has been involved in the research and development of hydrogen technologies. 45 experts in the fields of mechanical engineering, chemistry, physics, electrical engineering, process engineering and industrial engineering cooperate with industry and research in national and international projects for the production, distribution, storage and applications of hydrogen. Fields of activity include research, engineering, simulation and testing of electrolysis technologies, gas storage systems, fuel cells, refueling, measurement and safety systems. State-of-the-art R&D infrastructure includes test benches up to 1000 bar, a refueling facility for cars, buses/trucks and the fuel cell test bench up to 160 kW.



K1-MET is one of the leading international metallurgical competence centres for ferrous and non-ferrous metallurgy based in Austria. The cooperation partners are renowned national and international partners and deal with topics such as energy efficiency, circular economy and climate-neutral metal production. Only through cooperative research in these technological areas can resource efficiency and product quality be increased. In addition, the K1-MET GmbH is committed to global climate goals. Topics such as increased use of renewable energy or decarbonization must remain in focus in order to reduce CO2 emissions and achieve climate goals.


Vienna University of Technology

The Vienna University of Technology is Austria's largest research and educational institution in the field of technology and natural sciences. More than 4,000 scientists are researching "technology for people" in five main research areas at eight faculties. The content of the studies offered is derived from the excellent research. More than 27,000 students in 55-degree programs benefit from this. As a driver of innovation, TU Vienna strengthens the business location, facilitates cooperation and contributes to the prosperity of society. The participating institutes have many years of project experience and their research focus in the topics of renewable energies, circular economy and hydrogen.


University of Natural Resources and Life Sciences

Department of Agrobiotechnology, IFA Tulln – Institute of Environmental Biotechnology

At the IFA-Tulln, University of Natural Resources and Applied Life Sciences Vienna, microbial metabolic pathways are researched to safeguard the quality of life and preserve natural resources. The institute has well-equipped laboratories with state-of-the-art analytical equipment and corresponding infrastructure such as anaerobic high-pressure reactors and incubators, large-scale test facilities and a pilot plant for fermentations. These prerequisites enable numerous research cooperations with industrial partners and successful implementation of scientific results.

In the Department of Geobiotechnology (Andreas P. Loibner), microbial processes that occur naturally in soils, aquifers and oil/natural gas reservoirs are investigated with regard to technical applications. Metabolic capabilities and interactions of specific microorganisms are systematically analysed and optimised for large-scale technical application.



VERBUND is Austria’s leading energy company and one of the largest producers of electricity from hydropower in Europe. The Group generates around 95% of its electricity from renewable energy, primarily from hydropower. VERBUND trades electricity in 12 countries and generated around €3.2bn in annual revenue in 2020 with approximately 2,900 employees. With its subsidiaries and partners, VERBUND is active in the generation of electricity, transmission and in international trading and sales. VERBUND has been listed on the Vienna Stock Exchange since 1988 with 51% of the share capital being held by the Republic of Austria.

VERBUND is the key player for the success of the energy transition in Austria. The challenges that have to be met call for a unified focus throughout the entire company, which VERBUND is driving forward with Mission V. Mission V is a long-term and comprehensive transformation program and stands for the will to confront the climate crisis as a force for change. This program is based on the VERBUND Strategy 2030 with its three pillars: Strengthening the integrated home market, expanding renewable energies in Europe and establishing itself as a European hydrogen player. With Mission V, VERBUND is pushing the achievement of the strategic goals 2030 and ensuring their implementation.


voestalpine Stahl GmbH

voestalpine Stahl GmbH is the lead company of the Steel Division of the voestalpine Group. As a globally active manufacturer of high-quality steel products, the Steel Division plays a driving role in shaping a clean and livable future. In steel production, the Steel Division sets benchmarks in the current production route and is pursuing an ambitious step-by-step plan for climate-neutral steel production with greentec steel. With its high-quality steel strip, the Steel Division is the first port of call for renowned auto manufacturers and suppliers worldwide. It is also one of the most important partners to the European domestic and engineering industries. For the energy sector it produces heavy plate and cast products for applications in the most difficult conditions and offers tailored solutions for the expansion of renewable energy.


Verein WIVA P&G – Wasserstoffinitiative Vorzeigeregion Austria Power & Gas

The research association WIVA P&G (Hydrogen Initiative Austria Power & Gas) has set itself the task of promoting climate-neutral hydrogen and green gases in Austria. An important point here is to coordinate the energy showcase region of the same name. As a central energy storage region, energy transport hub and important location for renewable energy sources, Austria is ideally suited as an energy model region. In the coming years, WIVA P&G will demonstrate how Austrian technologies tested on the domestic market can contribute to the reduction of greenhouse gases and thus not only serve the Austrian economy as an export hit, but also make a significant contribution to the global reduction of greenhouse gas emissions.