To comply with the timeline of Swiss net-zero targets, an accelerated market development of sustainable fuels and platform chemicals (SFPC) is necessary. While first-generation technology is available to initiate a ramp-up the production of those substances, this is not the case for policies, laws, regulations, and markets (non-technical aspects).
A first aim of the reFuel.ch project is therefore concerned with investigating how investment security can be improved by closing these knowledge gaps. This must be done carefully, based on a broad understanding of sustainability criteria, to avoid misguided decisions and detrimental effects on future developments and implementation. The SWEET-reFuel.ch Consortium will develop robust and practical pathways for introducing SFPC to markets and the Swiss energy system (including unused domestic biomass) using an inter- and transdisciplinary approach. This will include inputs from social science (sociology, law, economics, and political science), natural sciences, and engineering, as well as the dialogue with policy makers, regulators, market actors, and end users - via regular thematic Round Table discussions. Within this framework, case studies for domestic, European, and non-European implementations will be evaluated and co-designed. A second aim is to strengthen innovative technologies currently at low technology readiness level. This will be achieved by focusing on green methanol pathways and other technologies with breakthrough potential for sustainable fuel and platform chemical production. The overall target is to improve sustainability and reduce costs by increasing efficiency, selectivity, and load-flexibility of plants in order to comply with long-term climate policy goals.

WP 1: Social, Economic, and Policy Assessment on National Level The replacement of fossil fuels with renewable ones may cause different impacts on Swiss society and the economy. For specific sectors, like aviation, roadmaps for sustainable developments are available and offer a first assessment of the incentives provided by those policy mixes. However, the sector overarching social and economic impacts of the implementation of policies in Switzerland towards net zero in the chemical sectors are not well known. No knowledge is available about the potential administrative barriers for the import of sustainable fuels, about efficient policy measures to foster the use of sustainable fuels and platform chemicals. The assessment of the social acceptance of such policy measures is missing as well. WP1 within SWEET-reFuel.ch has the task to assess the social, economic, and policy measures and impacts by applying the perspective of social science and humanities and aim at increasing the policy readiness level of the high-TRL technologies. Thereby the project ensures that an implementation of robust pathways for meeting future Swiss demands for fuels and platform chemicals, in a sustainable way, can be realized. Detailed objectives in which the Centre for Energy and the Environment is participating are:

• Develop policy instruments to enable the deployment of SFPC in Switzerland.
• Quantify the socio-economic impacts of using SFPC in Switzerland.

WP2 Social, Economic, and Policy Assessment on International Level A national strategy towards a sustainable and climate-friendly energy system can be strongly related to social, economic, and policy aspects on the international level, especially if large imports of energy or energy carriers are part of such a strategy as it possibly is for Switzerland. The political support of conventional biofuels has illustrated that national legislation (e.g., in the USA or the EU) has global socio-economic as well as environmental implications and led to legal disputes. Several political institutions have launched strategies to foster the use of sustainable fuels and platform chemicals. While most of SFPC are expected to be imported to Switzerland, implications on international markets, social impacts in exporting countries, and indirect environmental effects depend on the technology pathway and are unknown. Consequently, suitable policy instruments and implementation strategies must be developed with caution, carefully considering these interdependencies. Therefore, in WP2 of Sweet ReFuel.ch, the following objectives are pursued, to contribute to the assessment of robust pathways considering the international policy instruments: Further, the research contributes to the development of an interdisciplinary understanding of robust pathways by assessing the socio-economic implications and related but indirect impacts on land use and food security on potential exporting countries such as the Iberian Peninsula and Oman as well as on international markets. Detailed objectives of the project in which the Centre for Energy and the Environment is participating are:

• Assessment of the international law and policy landscape relevant to SFPC
• SFPC-relevant country risk analysis
• International trade in SFPC

WP3 Modeling of Robust Transition Paths The transition towards a sustainable energy system that meets Switzerland's greenhouse gas emission targets requires a feasible pathway that encompasses all sectors of the energy system. In WP3 within SWEET-reFuel.ch, we aim to determine robust transition scenarios towards these goals, including the production/provision of sustainable fuels and platform chemicals (SFPC) in the required quantities. This goal is achieved through a holistic energy system analysis using the Swiss Energy System Modelling Framework (SESMF). The ZHAW team of the School of Engineering will be involved in:

• Non-CO2 climate impact analysis
• Logistics optimization and requirement refinement for the synthesis, distribution, and use of Sustainable Aviation Fuels