Quantifying the Net Carbon Dioxide Emissions Impact of Electricity Interconnectors flows for Ireland and the All-Island system for 2024

As Ireland works towards ambitious climate targets, the role of electricity imports via interconnectors has become an increasingly significant part of the electricity mix. While domestic power generation emissions are reported in national emissions inventories, the emissions embedded in imported electricity remains unreported under current accounting methods, potentially distorting perceptions of national progress. This study aims to quantify the carbon emissions impact of Ireland’s interconnectors in 2024. To do this, the quantity of carbon embedded in imported electricity is found and compared with a counterfactual scenario, in which electricity imports are replaced by domestic generation, evaluating whether interconnection resulted in a net environmental benefit. The analysis includes imports through the Moyle Interconnector to Northern Ireland, the East–West Interconnector to the Republic of Ireland, and flows into the Republic via the North–South tie-line. Quarter-hourly data on carbon intensities and interconnector flows are used, allowing for emissions to be attributed on a time-sensitive basis rather than relying on annual grid averages. Findings indicate that interconnector imports abated over 634 thousand tonnes of CO₂ across the island of Ireland, and over 481 thousand tonnes of CO₂ for the Republic alone, when compared to domestic generation alternatives. Thus, electricity imports were found to be a net environmental benefit in 2024. However, these imports still carried a substantial carbon footprint, highlighting the need for clarity in emissions reporting frameworks.