As any analysis, the quantitative assessment used in this report has limitations. In particular, it is not fit to study some of the important linkages between water and energy outlined in Chapter 1. First, the modelling tools can only capture systemic effects that are noticeable in the top-down frameworks, and ignore important local bottlenecks with severe local consequences that may occur over short time spans. Secondly, there are significant data gaps (see e.g. OECD, 2010) that prevent a full representation of all the bottlenecks in the baseline and counterfactual projections of the modelling tools. Therefore, this Annex attempts to provide further insights on the consequences of this particular linkage. Given the large data gaps, some of the key consequences of the nexus bottlenecks can only be discussed in an anecdotal way. Nonetheless, the inclusion of these consequences in the evaluation of the bottlenecks is fundamental in providing an overview of the full costs of inaction on the nexus, and therefore in the assessment of the benefits of policy action.