Innovative Projects
Just a small step from gas storage to energy storage
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Innovative and development projects

NAFTA’s underground storage facilities are providing opportunities to develop its competence even in the innovative storage of renewable energy sources. Today, green energy can virtually be only stored on a limited scale and so it often remains unused. Nevertheless, NAFTA is among the innovators testing the storage of renewable energy sources in underground natural gas facilities.

NAFTA’s innovative projects mainly involve storing renewable energy sources and the use or storage of hydrogen.

All this started back at a time when ideas like this were not as strongly perceived by society as they are today. These efforts began in 2014, when NAFTA joined Underground Sun Storage as a consortium member and later worked on several projects with a number of major professional partners.


There is a strong view among us of the possibilities for cooperation between gas and renewable energy in the future. Our innovation department is devoting itself to the development of potential joint ventures both in this area and in our own projects, leveraging our unique know-how and synergies within the existing gas infrastructure.

These projects include NAFTA’s engagement with the photovoltaics sector. A total 142 solar panels located at central stations in Gajary and Plavecký Štvrtok have been successfully connected by us to generate 41.18 kW of nominal power. Once they have been inspected, the solar energy from them can be used for normal consumption directly at the plants.

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The company NAFTA a.s. also successfully participated in the Call aimed at supporting the construction of new facilities for the production of electricity from renewable energy sources financed from the Recovery and Resilience Fund. The result of our efforts to advance in this industry is reflected by the approval of co-financing from mechanism funds for the projects Construction of a photovoltaic power plant in the Centrálny Areál ​​Gajary (0.766 MW) and Construction of a photovoltaic power plant in the location Ptrukša (1.065 MW). The implementation of these projects is planned in 2023 and 2024.

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Joining a call from Important Projects of Common European Interest (IPCEI), NAFTA has succeeded in the national selection process for research, development and innovation projects and the Henri project was born.

We are seeking to identify both an appropriate location for storing hydrogen mixed with natural gas and the maximum possible concentration that could be stored in a porous geological structure.

The first phase of H2I S&D has experts seeking an appropriate location for storing hydrogen mixed with natural gas. Having identified an appropriate underground geological structure, laboratory research is being carried out to define the maximum permitted concentration of hydrogen. A broad spectrum of parameters would be researched, such as possible geochemical and microbial reactions and changes in the rocks.

The second phase of the project involves constructing a pilot test of the technology to generate hydrogen through water electrolysis. The hydrogen would then be mixed with natural gas at concentrations defined in the first phase of the project, with the mixture stored in underground facilities. The objective is not one-cycle testing, but rather to test multi-cycle production and injection in order to obtain more data about the impact and behavior of hydrogen stored underground, thereby creating a comprehensive image of how it can be stored in specific rock structures. Results from laboratory testing and the models thereby created will also be verified, with the models corrected by real data.

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The HyStorage research project aims to investigate the influence of hydrogen on porous rock formations in order to determine the feasibility and integrity of pore storage facilities for the storage of hydrogen. For this purpose, a specialized technical unit for the storage test was set up on a designated drilling site at Uniper Energy Storage's Bierwang site. Commissioning is currently in progress and first hydrogen will be injected from September onwards.

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  • Usage of existing well with existing storage infrastructure
  • Wellsite is located 3 km away from the Bierwang site
  • Three tests each consisting of : injection, storage, withdrawal

Uniper Energy Storage is the consortium leader, operator and responsible for the test under mining law. The consortium is further consisting of the companies OGE, RAG Austria, SEFE Securing Energy for Europe and NAFTA, which contribute their expertise, and is also supported by interdisciplinary partners from industry and science. The project has been approved by the Southern Bavarian Mining Authority.

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Joining another call, this time from the Fuel Cells and Hydrogen Joint Undertaking (FCH JU), NAFTA has successfully partnered with a broad consortium in two European projects, HyUsPRe and HYSTORIES.

They seek to explore the impact of hydrogen on porous layers underground.

Besides laboratory research, the project also includes specific models for a hydrogen network in Europe connected to underground storage facilities. More details about it will be forthcoming.


*This project has received funding from the Fuel Cells and Hydrogen 2 Joint Undertaking (JU) under grant agreement No 101006632. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and Hydrogen Europe and Hydrogen Europe Research.

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Underground Sun Storage

The most promising, innovative projects for the future particularly involve increasing the value of natural gas storage facilities, whether through more flexibility, efficiency or projects that concentrate on storing renewable energy sources. This is where Underground Sun Storage comes into play, where NAFTA has partnered with RAG. The project is in itself unique in Europe in that it took place under laboratory conditions and in the second phase directly at an exhausted natural gas deposit.

Underground Sun Storage showed that storing hydrogen mixed with natural gas in porous geological structures is technically feasible.


Natural gas network development plan

Besides these projects, NAFTA has staked out six others that have been incorporated into the Ten-Year Network Development Plan (TYNDP). The elements of this plan are listed below:

  • UGS Veľké Kapušany – constructing a natural gas storage facility near Veľké Kapušany and Ptrukša, which should also store renewable gases;
  • P2G Veľké Kapušany – exploring the option of using open air areas around Ptrukša to build a photovoltaic power plant;
  • UGS Láb H2 – addressing the possible adaption of existing technology to enable natural gas operation beyond 2025;
  • G2F – Gas to Future – examining the feasibility of installing a photovoltaic power plant at the Gajary central station and subsequently using electrolysis to produce hydrogen;
  • Biomethane could be produced and used as gas to fuel compressor turbines, whose operation would reduce CO2 emissions and lead to overall greening of natural gas storage;
  • Reducing methane emissions from UGS operation.

Underground gas storage facilities provide extensive capacity, advanced technology and background knowledge, so they have a promising future in energy storage. Because the green economy, and specifically hydrogen, are today key topics at both the European and national level, we believe that NAFTA will also be able to win public support here.