Additional Verification of the NAEI shipping model

This work builds on the NAEI shipping model revision undertaken by Ricardo. It entails additional validation work, through model sensitivity testing and further discussion with stakeholders to test assumptions, that will ensure the robustness of the model Additional information: Single Tender Action. Ricardo Environment and Energy have developed the model thus far. The remaining work is a refinement to the model that they have built. There are no alternative suppliers available with the level of understanding of the model that is required.