The global energy sector stands at a critical juncture, with the imperative shift towards renewable energy sources posing challenges and opportunities for existing infrastructure and societal norms. This thesis explores the multifaceted dynamics of transitioning energy systems, mainly focusing on Switzerland as a case study for innovative energy system planning and decentralization methodologies.

This thesis addresses the strain on energy infrastructure due to renewable energy integration. It presents a novel methodology to characterize energy vector grids and storage within the multi-energy and multi-sector modeling framework EnergyScope. It shows that optimal integration requires 61-82% reinforcement at local distribution grids, highlighting a strategic pivot towards renewable sources without significant transmission-level enhancements. This finding challenges the prevailing emphasis on transmission grid reinforcement, proposing a more nuanced approach to grid adaptation that balances intermittencies of renewable technologies, compensated by the Hydro Dam storage used at its maximal capacity of 8.9TWh in combination with Methane storage, thus increasing the seasonal Swiss storage capacity by 43-58%.

Exploring decentralized energy systems reveals that strategic decentralization can reduce system costs by 10% to annually 1230CHF/cap and enhance self-consumption by up to 68%compared to a centralized model. By juxtaposing decentralized and centralized energy planning models, this thesis illustrates the potential for hybrid models to foster system resilience and efficiency, thereby contributing to a more sustainable energy future, in contrast with traditional models, underscoring the importance of adaptive planning strategies.

Further analysis quantifies the roles of various actors in Switzerland's energy system decentralization, identifying the complexities of transitioning to decentralized, renewable energy sources. The emphasis on dynamic interactions among system actors introduces a new perspective on optimizing energy systems for sustainability and equity, challenging conventional approaches by advocating for a strategic balance that accommodates regional variations and actor-specific dynamics. Applying the methodology identifies the tradeoffs between the energy system service providers and the regional prosumers, leading to energy service costs of 2-8CHF/m2 ERA for Alpine districts and at a maximum of 32-125CHF/m2 ERA for urban districts under the assumption of a guaranteed profit of 5% for the energy system service providers.

Lastly, the thesis aims at understanding the trade-offs between environmental and economic objectives in energy system planning. By implementing LCA metrics in the energy system modeling, we demonstrate the potential for aligning economic efficiency with environmental sustainability by reducing system costs by 15% to 47% alongside a 31-81% reduction in environmental impacts, cautioning against burden-shifting risks. Using multi-objective optimization and uncertainty analysis, we demonstrate that optimizing for environmental indicators leads, at the same time, to economic and environmental benefits in each area of protection compared to the current system. In contrast, environmental indicators correlate, but compromise at environomic scales needs to be taken. [...]