The global transition toward low-carbon energy systems has intensified interest in offshore renewable energy (ORE), particularly floating offshore wind turbines (FOWTs) and wave energy converters (WECs). As competition for offshore space increases, integrating multiple technologies within a single multi-use energy park has emerged as a promising strategy to enhance spatial efficiency while potentially reducing environmental impacts. However, existing research largely evaluates these technologies in isolation, leaving the environmental implications of shared infrastructure underexplored. This thesis addresses this gap by assessing the life cycle environmental performance of co-located offshore wind and wave energy systems compared with standalone deployments.

This study conducts a cradle-to-grave Life Cycle Assessment (LCA) using both the EF 3.1 and IMPACT World+ methodologies. Three 180 MW scenarios are modeled: a standalone floating wind farm (12 OFWTs), a standalone wave energy park (450 WECs), and a co-located wind-wave park (10 OFWTs + 75 WECs), with shared substation and export cabling infrastructure. Engineering-based models are developed to calculate Annual Energy Production (AEP), capacity factors, and component-level material inventories, while openLCA is used to quantify greenhouse gas emissions and broader environmental impacts. Energy Payback Time (EPBT) and Greenhouse Gas Payback Time (GPBT) are further computed to evaluate energy and climate performance over the systems’ lifetime.

Results show that shared infrastructure substantially reduces material demand, vessel use, and installation requirements in the co-located scenario, leading to lower embodied impacts per kilowatt-hour compared to the sum of standalone systems. However, differences in capacity factor estimation and technology convergence influence the distribution of environmental burdens between wind and wave subsystems. Across all scenarios, the manufacturing stage—particularly steel and copper—dominates total impacts. The analysis also highlights how future energy grid decarbonization could extend GPBT values, as improvements in background electricity mix reduce upstream emissions.

Overall, this thesis demonstrates that co-locating offshore wind and wave energy can deliver measurable environmental benefits through shared infrastructure and optimized spatial planning. The findings provide new quantitative evidence for policymakers, developers, and marine planners seeking integrated offshore renewable strategies and highlight methodological pathways for future LCA studies that assess hybrid ORE systems.