Assessment of emissions from the Croatian nautical charter fleet using Tier 1 methodology: insights from a 2023 pilot study

This study examines emissions from the rapidly growing nautical tourism sector in Croatia, a major hub for charter and leisure boat tourism, focusing on the significant emissions caused by vessels that lack advanced emission control systems. Despite intensive petrol and diesel consumption, emissions from this sector remain under-researched; this study addresses that gap using data from the Green Sail Association’s Ecological Footprint Calculation Platform, collected during a 2023-24 pilot project in selected marinas in the Šibenik-Knin and Split-Dalmatia counties. The sample includes sailboats, yachts, and catamarans 10 to 20 m in length. Operational data (engine hours, fuel consumption, technical specifications) were gathered from charter companies and skippers. Emissions of CO2, NOX, CO, and PM were calculated using EMEP/EEA Tier 1 methodology based on fuel consumption and emission factors. Emissions rise with vessel length and are notably higher for catamarans due to greater fuel consumption. Though only 35 % of the sample, catamarans contributed nearly 60 % of total emissions. Based on the findings on the sample of 160 vessels, extrapolated to Croatia’s fleet (~4,500 vessels), seasonal emissions are estimated at 30,000 to 40,000 t CO2, 300 to 400 t NOX, 100 to 150 t CO, and 15 to 25 t PM. This study represents the first large-scale emissions estimate for charter vessels and recommends further research with a more representative sample, broader geographical coverage and advanced methods such as Tier 3 calculations, collection of generator fuel consumption data and real-world emissions measurements to improve emission factors.