A systematic comparison and optimization of thermo-chemical hydrogen production processes with CO2 capture is performed. The process options include the resource type, the syngas production method and the hydrogen purification technology, including CO2 separation by ab- or adsorption or membrane processes. With regard to climate change mitigation, the removed CO2 can be compressed for storage. To analyze the competitiveness of different CO2 capture options and H2 process alternatives a consistent multi-objective optimization methodology combining energy-flow models with process integration techniques and economic and environmental evaluation is applied. The potential of efficient decarbonization in fossil and renewable H2 processes is highlighted.