Onshore Power Supply Readiness in Adriatic–Ionian Ports: A Multiple-Case Assessment and Typology for Marine Spatial Planning and Port Governance

The onshore power supply (OPS) eliminates ship emissions at berth, yet feasibility is site-specific, and most evidence concerns large Northern European and Asian ports. This multiple-case study assesses OPS readiness at six ports of the Adriatic–Ionian macro-region (Ancona, Ploče, Durrës, Volos, the river port of Belgrade, and the lake port of Ohrid) covering ferry, cruise, cargo, and tourism in the European Union (EU) and non-EU jurisdictions. A common protocol and rule-based SWOT (strengths, weaknesses, opportunities, and threats) coding within and across cases yield a regional factor set traceable to supporting ports, a thematic classification, an exploratory readiness typology with decision rules, and the factor pairings behind tier-specific strategic options. The binding constraints are grid capacity, capital cost and its allocation, and, outside the EU, a missing mandate; electricity price relative to fuel governs utilisation, and the climate benefit depends on grid carbon intensity, quantified by port. The 2030 EU obligations cover only container and passenger ships above 5000 gross tonnage at ports above the call thresholds; bulk, tanker, inland, lake, and small-ferry traffic is excluded. The case evidence identifies OPS readiness as a marine spatial planning and governance task and yields a priority option per tier and four propositions for similar ports.