Underground Sun Storage

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The Austrian research project Underground Sun Storage , led by RAG Austria AG , started in mid-2013 and was successfully completed in 2017. The aim of the project was to research large-volume and seasonal storage options for renewable wind and solar energy converted into hydrogen in former natural gas reservoirs . The basis for this is the " power-to-gas " technology, through which the electricity from renewable energy is converted into hydrogen by means of electrolysis and can thus be stored in the existing storage infrastructure.

For this purpose, laboratory tests, simulations and an in-situ test on an industrial scale were successfully carried out on an existing sandstone deposit, the properties of which are comparable to the large natural gas deposits of RAG in Austria.

Historically, adding hydrogen to methane is nothing new. The Viennese town gas , which was used for heating and lighting in Vienna until the 1970s, already consisted of 51% hydrogen.

Results

Proof of the compatibility of hydrogen admixtures in former natural gas reservoirs of up to 10% could be provided. This means that there is the option of storing large volumes of renewable energy seasonally and using the existing storage infrastructure for this. In addition, the potential was identified for natural gas reservoirs to convert hydrogen and carbon dioxide into natural gas using a microbiological process (hydrogenotrophic methanogenesis , worldwide patent from RAG).

The results from the "Underground Sun Storage" project thus form the basis for the follow-up project " Underground Sun Conversion ", which started in 2018 , the aim of which is to produce "green gas" in a natural process from hydrogen (H 2 ) and carbon dioxide (CO 2 ) naturally produced and stored in large quantities in existing (pore) natural gas reservoirs. This binds CO 2 and creates a sustainable carbon cycle . This follow-up project is also being funded by the Austrian Federal Government's Climate and Energy Fund as a lead project with almost 5 million euros.

The Underground Sun Storage project was initiated by RAG Austria AG and implemented together with the partners Montan University Leoben , University of Natural Resources and Life Sciences - Department IFA Tulln , Axiom Angewandte Prozesstechnik GmbH, Energy Institute at the JKU Linz and Verbund AG . The project was funded by the Austrian Climate and Energy Fund as a lead project with 2.8 million euros. The total cost of the project was 4.5 million euros.

background

The climate targets of the EU and the European governments stipulate a rapid expansion of the decarbonised energy system and renewable energy sources.

This also increases the need for large-volume and seasonal storage facilities with which the seasonal fluctuations in energy harvest (summer sun) and energy demand (winter) can be balanced and a high level of security of supply can be guaranteed. Because in most cases renewable energy sources can only be controlled to a limited extent. Neither wind nor sun are not based on current energy consumption. Electricity grids cannot store energy, but solutions such as pump and battery storage systems make a contribution to daily or hourly compensation. In principle, however, the network operators are forced to adjust production exactly to demand and, if necessary, to reduce and switch off overproduction. But if it is possible to store large amounts of electricity in the form of hydrogen and feed it back into the grid when required, this leads to a sector coupling between electricity and gas and, at the same time, to a decoupling of generation and consumption. Seasonal compensation can only be achieved through large-volume gas storage facilities that can provide gas at any time and with high output.

procedure

The project was divided into two phases. Phase I comprised basic investigations with the aim of clarifying the feasibility of a field test. In particular, it was necessary to prove that the external integrity of an underground gas storage facility is not impaired by hydrogen admixtures of 10 percent. Phase II included the planning, approval, construction and operation of a field test facility at a small, isolated natural gas storage facility in the Vöcklabruck / Austria area. The work was carried out on the basis of the geological situation in the foothills of the Alps (Molasse zone) and took into account the technical conditions of commercial underground gas storage facilities of RAG Austria AG. It was important to gain practical and interdisciplinary knowledge on the subject of hydrogen in pore storage for the first time and to substantiate this with a field test.

Web links

Individual evidence

  1. ↑ a b c Underground Sun Storage: Publishable final report (PDF) of October 31, 2017, accessed on May 1, 2020
  2. ↑ Method for hydrogenotrophic methanogenesis of h2 and co2 to ch4 on Google Patents, accessed on May 1, 2020
  3. ^ Project presentation of "Underground Sun Conversion" on the website of the Climate and Energy Fund , accessed on May 1, 2020
  4. ^ Project description of "Underground Sun Storage" on the website of the Climate and Energy Fund , accessed on May 1, 2020