Lisa Kühberger

The achievement of global climate targets outlined in the Paris Agreement represents a critical challenge in the coming decades. Certain industry sectors cannot completely avoid all emissions from their processes. In this context, the term unavoidable or Hard-to-abate emissions is used. Carbon Capture and Utilization (CCU) and Carbon Capture and Storage (CCS) are recognized as essential components for addressing those emissions to achieve Net Zero Emissions. To identify effective Carbon Management Strategies, balancing future CO2 sources and possible sinks for achieving long-term climate targets is essential. Especially in Austria hardly any comprehensive studies have been carried out. This work presents a comprehensive analysis of Austria’s CO2 point sources as well as their projected development until 2050 based on technology-based scenarios. Geological CO2 storage in Austria is primarily feasible in former hydrocarbon reservoirs and saline aquifers. Future demands for CO2 as CCU feedstock will arise in the chemical industry. By 2050, industry will emit approximately 4 Mt of unavoidable CO2 annually. These emissions must be stored in the long term and correspond to the minimum demand for CCS. Fugitive emissions from agriculture, for example, cannot be captured. Thus, they are not subject of CCU/S measures. Negative emissions are therefore necessary to achieve the climate targets. These negative emissions and the possible use of CO2 as feedstock are covered by biogenic CO2.

Achieving climate neutrality requires a massive transformation of current energy systems. Fossil energy sources must be replaced with renewable ones. Renewable energy sources with reasonable potential such as photovoltaics or wind power provide electricity. However, since chemical energy carriers are essential for various sectors and applications, the need for renewable gases comes more and more into focus. This paper determines the Austrian green hydrogen potential, produced exclusively from electricity surpluses. In combination with assumed sustainable methane production, the resulting renewable gas import demand is identified, based on two fully decarbonised scenarios for the investigated years 2030, 2040 and 2050. While in one scenario energy efficiency is maximised, in the other scenario significant behavioural changes are considered to reduce the total energy consumption. A techno-economic analysis is used to identify the economically reasonable national green hydrogen potential and to calculate the averaged levelised cost of hydrogen (LCOH₂) for each scenario and considered year. Furthermore, roll-out curves for the necessary expansion of national electrolysis plants are presented. The results show that in 2050 about 43% of the national gas demand can be produced nationally and economically (34 TWh green hydrogen, 16 TWh sustainable methane). The resulting national hydrogen production costs are comparable to the expected import costs (including transport costs). The most important actions are the quick and extensive expansion of renewables and electrolysis plants both nationally and internationally.

The energy transition from fossil-based energy sources to renewable energy sources of an industrialized country is a big challenge and needs major systemic changes to the energy supply. Such changes require a holistic view of the energy system, which includes both renewable potentials and consumption. Thereby exergy, which describes the quality of energy, must also be considered. In this work, the determination and analysis of such a holistic view of a country are presented, using Austria as an example. The methodology enables the calculation of the spatially resolved current exergy consumption, the spatially resolved current useful exergy demand and the spatially resolved technical potential of renewable energy sources (RES). Top-down and bottom-up approaches are combined in order to increase accuracy. We found that, currently, Austria cannot self-supply with exergy using only RES. Therefore, Austria should increase the efficiency of its energy system, since the overall exergy efficiency is only at 34%. The spatially resolved analysis shows that in Austria the exergy potential of RES is rather evenly distributed. In contrast, the exergy consumption is concentrated in urban and industrial areas. Therefore, the future energy infrastructure must compensate for these spatial discrepancies.