Decarbonization under seasonal pressure: Integrated Energy-Water-Economy modelling of tourism-driven peaks in Greece and Cyprus

Tourism is the economic backbone of many Mediterranean communities, but its benefits come with a hidden problem: the seasonal surge of visitors concentrates energy and water demand into a few months each year. This report asks a practical question: can national decarbonization plans that succeed on annual targets also ensure reliable service and water security during short, intense tourism peaks? To answer this, we built an integrated modelling framework linking a global economy model (GTAP-E) with a detailed energy model (LEAP) and a water-withdrawal module (WaterReqGCH), and we ran coherent Business-as-Usual and National-Commitment scenarios to 2050 for Greece and Cyprus. Three headline messages emerge: - First, National-Commitment measures deliver major gains on annual metrics: economy-wide technology and efficiency changes cut annual energy-sector emissions dramatically in both countries and reduce long-run final energy needs compared with unchecked growth. - Second, and crucially, annual success does not automatically remove seasonal risk: when we translate economy-wide activity into monthly energy and water profiles using observed post-pandemic tourism seasonality, tourism-linked sectors (air and water transport, accommodation and tourism services) still generate strong summer peaks (often close to or above current peak levels) even under ambitious decarbonization assumptions. So, these countries can be "on track" for net-zero on paper while still being vulnerable to summer outages and water shortages in practice. - Third, the shape of seasonality matters for policy: Greece shows sharper, higher mid-summer peaks concentrated in a few months, while Cyprus shows a longer high-season plateau. This difference implies different operational and investment priorities between the two countries (short, intense surge management in Greece; extended seasonal resilience in Cyprus). These results come from an intentionally conservative, policy-oriented design: GTAP-E produces macro-consistent sectoral activity paths, LEAP converts those into sectoral energy and emissions outcomes under NECP measures, and WaterReqGCH disaggregates annual withdrawals into months using tourism and agricultural seasonality proxies. The chain preserves economy-level consistency while making intra-annual peaks visible-an assessment style that is still rare in national (annual) planning exercises. For policymakers the implications are straightforward and actionable, summarized in our final section: - Add peak-aware diagnostics to energy and water plans: require scenario tests that report peak-month electricity demand in tourism-linked services, peak system adequacy metrics (summer capacity margin, stress hours), and peak-month water-stress indicators. - Target peak drivers, not just annual averages: accelerate efficiency and demand-management in accommodation and tourism services, promote temporal pricing and incentives to shift demand to shoulder months, and prioritize shore-power, electrified services at airports and ports. - Coordinate energy and water operations where peaks co-locate (islands, coastal ports): schedule maintenance outside peak windows, align desalination and pumping plans with expected seasonal electricity supply, and embed contingency rules in water management plans. - Tailor strategies to the national seasonality signature rather than applying a one-size-fits-all approach across the region. This report does not claim to forecast the future; it offers a robust diagnostic: under realistic activity trajectories, tourism seasonality remains a potential operational constraint even when countries are reducing annual emissions. That diagnostic should reshape how we judge decarbonization progress: success must be measured by both annual climate metrics and seasonal operational resilience. The modelling framework and policy steps documented here provide a practical blueprint for other tourism-intensive, water-sensitive regions that face the same trade-offs between greener energy systems and the resilience needed to serve peak-season communities and visitors.