Trade-offs in technical and environmental performance of water utilities: Insights focused on water-energy-carbon nexus

Within the water-energy-carbon nexus, understanding the trade-offs among resource use, drinking water delivery, and greenhouse gas emissions is essential for ensuring the sustainable provision of drinking water. Addressing this challenge, this study estimates four performance indices—technical efficiency, ecological efficiency, process environmental quality efficiency, and overall efficiency —using a unified framework based on Data Envelopment Analysis. The analysis was conducted under two scenarios, reflecting water companies’ prioritization of production and environmental dimensions. The empirical application, performed on a sample of English and Welsh water companies, revealed that water companies focused on technical efficiency, achieving average scores of 0.648 and 0.798 under environmental and production prioritization scenarios, respectively. In contrast, process environmental quality and ecological efficiency metrics were considerably lower, with average values of 0.179 and 0.129 for the environmental scenario and 0.153 and 0.131 for the production scenario. The temporal evolution of these performance indices highlights a trade-off between technical efficiency and performance indices integrating carbon emissions under the environmental prioritization scenario.