Techno-Economic and Environmental Assessment of Electricity-Based Renewable Hydrogen and its Derivatives

Climate change mitigation requires transforming the energy system through the adoption of low-carbon technologies, such as renewable electricity generation and electrification. Yet, electrification has limits. Hard-to-abate sectors require high-temperature heat or specific energy carriers, and areas such as long-distance aviation remain infeasible to electrify. Low-carbon hydrogen and its derivatives, produced, among others, from low-carbon electricity via power-to-X applications, can replace fossil-based energy carriers in these sectors. Their development involves many stakeholders, ranging from end-users to policy-makers, who shape the future hydrogen economy while raising technical, economic, and environmental challenges.

This thesis advances research on the hydrogen economy through techno-economic and environmental assessments of electricity-based renewable hydrogen and its derivatives. The first part examines how regulated electricity supply conditions influence renewable kerosene production in a German power system model. Due to limited renewable potential in industrialized countries, large-scale imports of hydrogen and derivatives are expected. ... mehrThe second part develops a comprehensive, multi-method approach for modeling and evaluating stand-alone power-to-X facilities, optimizing technical setups in terms of both economic and environmental objectives. This enables multi-objective optimization across global sites, generating Pareto-optimal trade-offs for decision-making on costs, carbon intensity, and capacity needs. To address renewable variability, the optimization is developed using adaptive robust optimization, focusing on production costs to ensure reliable system operation under uncertain weather conditions. Computational expenses are addressed using representative data. The final contribution introduces a heuristic-inspired branch-and-bound algorithm that identifies the most cost-efficient transport and conversion routes among seven commodities and three transport modes, with high spatial resolution and global coverage of production sites and infrastructure.

The German power system analysis shows that electricity supply conditions closely link electrolysis demand to renewable generation. Reduced capacity factors necessitate additional electrolysis and storage capacities to maintain steady synthesis; however, this results in only slight increases in carbon abatement costs. The stand-alone facility assessment reveals that locations with windy conditions achieve lower costs and emissions, while those with sunny conditions have higher emissions due to carbon-intensive module production and lower capacity factors. The cost advantage of windy locations persists under robust optimization, though long-term uncertainties increase costs. Locations with mixed capacity factors benefit from combining low-cost wind electricity with stable solar generation. The infrastructure analysis highlights natural gas pipelines as key assets for supplying large volumes of low-cost, low-carbon hydrogen and derivatives. With Germany as a destination, imports from Northern Africa, the Middle East, Central Asia, and Northern Europe can be achieved at low costs, especially if pipelines are retrofitted for hydrogen. Ammonia and methanol emerge as preferred commodities for seaborne transport.