The storability of hydrogen produced by converting solar energy has been demonstrated at a small depleted gas reservoir in Upper Austria.
The Underground Sun Storage project was launched in 2013 and completed in 2017. Its purpose was to investigate the hydrogen tolerance of storage infrastructure, so as to demonstrate the feasibility of large-scale seasonal storage of renewable energy in former gas reservoirs by means of the admixture of hydrogen produced from renewables to the natural gas in place.
In nature, carbon and hydrogen have evolved as primary sources of energy, and the main ways in which energy is stored. We have taken these processes as a model and imitated them with so-called “power-to-gas” technology. This permits the conversion of surplus electricity into hydrogen or synthetic methane, large quantities of which could then be stored in existing gas infrastructure.
Building on the knowledge gained from the Underground Sun Storage project, RAG initiated a follow-up project, carried out by an international consortium that has been under way since March 2017. This lighthouse project is being financed by Austria’s Climate and Energy Fund as part of its energy research programme.
Energy is never lost ...
Hermann Ludwig Ferdinand von Helmholtz
Natural gas on the move
Transportation is indispensable to any functioning economy. Unfortunately, however, road traffic causes about 45% of all emissions in the European Union.
The binding EU climate targets for heavy-duty vehicles require CO2 emissions from new trucks to fall by 15% by 2025, and by 30% by 2030 (reference level 2019).
The use of gas as a fuel can make a major, direct and immediate contribution to hitting the climate targets as natural gas is by far the most eco-friendly conventional energy source. Because of this numerous EU initiatives call for the increased use of CNG and LNG, as well as electric vehicles.
LNG – Liquefied Natural Gas
LNG is natural gas that has been converted to a fluid state by cooling it to a temperature of around -160°C. The expansion ratio of natural gas from liquid to gaseous form is 1:600, meaning that large volumes of energy can be transported and stored as LNG.
Because of this LNG is suitable for long-distance, heavy vehicle traffic. In comparison with diesel, emissions of sulphur oxide and fine particulates from vehicles running on LNG are 95% lower, while nitrogen oxide emissions are over 80% and CO2 emissions up to 20% lower. Noise emissions from LNG vehicles can be up to 50% lower than those of diesel vehicles.
RAG aims to market LNG made from renewables (“green gas”) for use as a transportation fuel and thus to offer a „climate-neutral“ fuel („e-fuel“).
CNG - Compressed Natural Gas
CNG has long been used in Austria as a fuel for cars, heavy goods vehicles and buses because it is exceptio- nally economical, safe and clean.
Since natural gas has a high hydrogen and low carbon content, up to 20% less CO2 is released than with petrol. As compared to diesel, nitrogen oxide emissions are 95% lower, and in comparison with petrol. The main emission from gas combustion is steam – and CNG vehicles emit virtually no fine particulates. Using CNG vehicles can significantly improve air quality, especially in urban areas. At the same time, CNG vehicles are 50% quieter than their petrol or diesel engined counterparts.
RAG has operated public, self-service gas filling stations at its sites in Gampern and Kremsmünster since 2014, and plans to roll out its forecourt network as market developments dictate.
Reuse of natural reservoirs and wells
We are working hard on innovative, sustainable projects designed to promote decentralised energy supplies. Besides the conversion of depleted gas reservoirs into storage facilities, this involves the geothermal after-use of non-commercial or depleted wells. For example, geothermal projects in Fürstenfeld, Munich’s Riem district, and the twin towns of Simbach and Braunau (on the border between Bavaria and Upper Austria), as well as some Styrian spas (Loipersdorf, Blumau and Walters- dorf), go back to previous drilling by RAG.
A successful pilot project – a deep borehole heat ex- changer working in tandem with a local biomass plant – supplied more than 100 households in Neukirchen an der Vöckla with environmentally-friendly heating tapped 2,850m below ground.
RAG is one of the partners in Wien Energie’s GeoTief Wien R&D project, which is carrying out a geological survey of eastern Vienna and its outskirts with a view to identifying the potential for environmentally friendly heating sourced from deep hot water reserves. To this end, 2D seismic was shot during the spring of 2017, and in autumn 2018 the resultant knowledge was deepened by a 3D seismic campaign.
Goals and Measures (PDF)