The influence of service level on the economic viability of Onshore Power Supply (OPS) systems - A case study

The implementation of Onshore Power Supply (OPS) systems is recognised as an effective strategy to reduce air emissions and noise pollution from ships at berth, thereby supporting decarbonization goals established by the European Union. Despite its environmental advantages, the economic viability of OPS remains one of the main barriers to its widespread adoption in ports. In particular, limited research attention has paid to the extent to which the service level provided by OPS infrastructure affects the financial performance of such investments.This paper addresses this gap by analysing the relationship between service level and economic viability through a case study of the Southern Container Terminal at the Port of Leixões (Portugal). Three investment scenarios were evaluated, corresponding to the installation of one, two, and three OPS systems, delivering service levels of 65%, 94%, and 100%, respectively. A 20-year financial analysis (2025–2044) was conducted using Net Present Value (NPV), Internal Rate of Return (IRR), and Payback Period as key indicators, under discount rates of 3% and 5%.The results demonstrate that service level significantly influences investment feasibility. The scenario with a 65% service level is economically unviable, presenting negative NPVs and an IRR below the cost of capital. In contrast, the 94% and 100% service level scenarios generate positive NPVs (at 3%) and IRRs slightly above 5%, indicating moderate but acceptable profitability. However, increasing the service level from 94% to 100% does not produce a proportional improvement in financial returns, revealing diminishing marginal gains relative to the intermediate scenario.The findings indicate that maximising service level does not necessarily maximise economic attractiveness. Instead, an optimal balance between infrastructure capacity and expected demand is essential to ensure financial sustainability while delivering substantial environmental benefits. These findings offer practical guidance for port authorities and policymakers seeking to design economically viable OPS systems.