The study investigates the environmental impacts of deploying larger (15 MW) versus smaller (5 MW) wind turbines in offshore wind farms, focusing on the North Sea. Using a high-resolution regional climate model (COSMO-CLM) with wind farm parametrization, the research examines the effects on power generation and air-sea fluxes. Key findings include: 1. **Power Generation**: Larger turbines increase the capacity factor by 2-3%, enhancing efficiency. 2. **Wind Speed and Turbulent Kinetic Energy (TKE)**: Larger turbines have a slightly smaller impact on 10 m wind speed (1.2-1.5%) and near-surface TKE (0.1-0.2%), leading to reduced effects on sea surface heat fluxes. 3. **Net Heat Flux**: Larger turbines result in a stronger reduction in net heat flux (0.6-1.3%) compared to smaller turbines. 4. **Air-Sea Fluxes**: These reductions in heat fluxes are crucial for ocean dynamics and marine ecosystems. 5. **Wake Effects**: The wakes generated by larger turbines are slightly stronger and extend further downwind, affecting downstream wind farms. 6. **Clouds and Radiation**: Larger turbines have a minimal impact on cloud fraction and precipitation but can modify low-level clouds, reducing solar radiation. The study suggests that larger wind turbines may offer advantages for ocean dynamics and marine ecosystems, supporting the EU's carbon-neutral goals. However, careful planning is necessary to mitigate the environmental and ecological impacts of large offshore wind farms.The study investigates the environmental impacts of deploying larger (15 MW) versus smaller (5 MW) wind turbines in offshore wind farms, focusing on the North Sea. Using a high-resolution regional climate model (COSMO-CLM) with wind farm parametrization, the research examines the effects on power generation and air-sea fluxes. Key findings include: 1. **Power Generation**: Larger turbines increase the capacity factor by 2-3%, enhancing efficiency. 2. **Wind Speed and Turbulent Kinetic Energy (TKE)**: Larger turbines have a slightly smaller impact on 10 m wind speed (1.2-1.5%) and near-surface TKE (0.1-0.2%), leading to reduced effects on sea surface heat fluxes. 3. **Net Heat Flux**: Larger turbines result in a stronger reduction in net heat flux (0.6-1.3%) compared to smaller turbines. 4. **Air-Sea Fluxes**: These reductions in heat fluxes are crucial for ocean dynamics and marine ecosystems. 5. **Wake Effects**: The wakes generated by larger turbines are slightly stronger and extend further downwind, affecting downstream wind farms. 6. **Clouds and Radiation**: Larger turbines have a minimal impact on cloud fraction and precipitation but can modify low-level clouds, reducing solar radiation. The study suggests that larger wind turbines may offer advantages for ocean dynamics and marine ecosystems, supporting the EU's carbon-neutral goals. However, careful planning is necessary to mitigate the environmental and ecological impacts of large offshore wind farms.