The water and sewage industry has fundamental links to all aspects of sustainability, being responsible for delivering potable water and treating wastewater, a social necessity, which requires significant amounts of energy, physical infrastructure, and financial investment. By utilising benchmarking and performance analysis, companies can identify and prioritise areas for improvement and learn from best practices.
This research embraces and expands on these themes over four main results chapters. Chapter 3 evaluates the economic and emission performance of UK and Irish water companies and identifies the key factors that affect their performance using a double-bootstrapped data envelopment analysis approach. That chapter found the companies could reduce economic and environmental inputs by 19.4% and 15.8% and provides an elementary framework to assess the influence of rurality on operational efficiency, applying it across a set of English and Welsh water companies. Chapter 4 again uses double-bootstrapped data envelopment analysis but evaluates the energy and economic efficiency of water (only), and water and sewerage, utilities in England and Wales, along with appraising the role of some rarely assessed explanatory factors. For example, results suggested that the proportion of water passing through the largest 50% of treatment works exhibited a significant negative effect on economic efficiency and average pumping head height had a significant negative effect for energy efficiency. Moreover, Chapter 4 determines the extent to which proxies may influence efficiency rankings and their determinant variables. Chapter 5 uses several sets of variables within the scope of the Hick-Moorsteen Productivity Index to examine the best approach for a comprehensive sustainability evaluation. Additionally, it investigates productivity change on a sample of UK water companies and disaggregates results for individual companies allowing an investigation of areas for improvement, indicating that the sample improved by 1.8% between 2014-18. Chapter 6 uses 350 companies from 42 countries to explore the energy intensity and reasons for varying performance of wastewater treatment on an international scale, using the most up-to-date data available and an effluent quality control to align performance. The global average electricity consumption for wastewater treatment was 0.89 kWh/m3 however, EU companies had the highest average energy intensity at 1.18 kWh/m3. Furthermore, Chapter 6 assesses the carbon impacts of energy intensities across regions and evaluates areas for improvement in international benchmarking practices.
Collectively, the research presented in this thesis can be of use to water industry operators, regulators, benchmarking organisations, and academics by providing new insight into water-energy efficiency within the water sector, and by developing improved methodologies for efficiency benchmarking.