Underground Sun Storage

Renewable energy sources are indisputably central to environmental sustainability, which is of the greatest importance to NAFTA. This is why we became a partner of the Underground Sun Storage project, created in accordance with the Power to Gas concept.
Underground Sun Storage is a unique project to verify the possibility of storing energy from renewables in underground geological structures in the form of a natural gas and hydrogen mixture. Such technology could become one of the future possibilities for storing the large surpluses of energy from renewable sources. Such energy can currently only be stored to a limited extent and therefore often remains unused. A solution to this problem would increase the attractiveness of renewable energy systems, allow them to grow further and ultimately result in a significant reduction in global CO2 emissions.
Thanks to its extensive experience with underground storage facilities, NAFTA was a partner in reactive transport modelling, the analysis of the impact on subsurface completion, the development of the technical proposal and supplying the compressor for the testbed facility.
The project consisted of various phases.  After laboratory tests were finished, the simple tesbed facility was constructed in Pilsbach, Austria. The testbed facility included the electrolysis unit for hydrogen production and also the compressor unit for injection of the hydrogen and natural gas mixture into the reservoir. Within the project, 1.2 million cubic metres of the natural gas with 10% volume of hydrogen was injected and withdrawn in and from underground geological structures. 
The testing operation of the hydrogen and natural gas mixture storage was successfully completed in 2017. 
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