Evaluating the Effectiveness of Residential Water Efficiency Initiatives in England: Influencing Factors and Policy Implications

Providers of municipal water supply services worldwide are facing pressure from climate change and increasing water demand due to growing populations and lifestyle changes. With finite global freshwater supplies, there is need for water service providers to consider water demand management as an option for closing the supply-demand gap. Several water utilities in the UK are implementing residential water efficiency initiatives, but to-date, the effectiveness of these programmes have not been comprehensively evaluated. The present study uses statistical analysis to evaluate the effectiveness of a domestic water efficiency programme, initiated by a major water supply company in South East England. Using multilevel regression, water consumption, weather and demographic data, the study analysed water savings achieved through the efficiency programme and defined the factors that affect a household’s potential to save water. Analysis showed that households that participated in the programme reduced their per capita consumption by approximately 15%. Importantly, research findings provide strong evidence that single resident and financially stretched households have a bigger potential to conserve water than wealthier and larger households do. This study also highlights the robustness of multilevel analysis, even in cases of data limitations. The findings generate implications for policy and practice, which are useful for water companies involved in implementing water efficiency programmes, as well as their evaluation

Estimating scenarios for domestic water demand under drought conditions in England and Wales

This paper presents preliminary results from the development of IMPETUS model, a domestic water demand microsimulation model which was developed to estimate the results of a range of scenarios of domestic demand under drought conditions. The model is intended to enable water resource management practitioners to assess the likely impact of potential interventions in particular catchment areas. It has been designed to be driven by seasonal catchment level forecasts of potential hydrological droughts based on innovative climate and groundwater models. The current version of the model is driven by reconstructed historical drought data for the Colne catchment in the East of England from 1995 to 2014. This provides a framework of five drought phases (Normal, Developing, Drought, Severe and Recovering) which are mapped to policy driven interventions such as increased provision of water efficiency technologies and temporary water-use bans. The model uses UK Census 2011 data to develop a synthetic household population that matches the socio-demographics of the catchment and it microsimulates (at the household level) the consequences of water efficiency interventions retrospectively (1995-2014). Demand estimates for reconstructed drought histories are presented to demonstrate the potential value of the model in supporting cost-benefit analysis of specific interventions. We conclude by discussing future directions for the work

The over-prediction of energy use by EPCs in Great Britain: A comparison of EPC-modelled and metered primary energy use intensity

This analysis compares the difference between the Energy Performance Certificate (EPC)-modelled and smart-meter measured annual energy use on a like-for-like basis in 1,374 gas-heated British households from the Smart Energy Research Lab (SERL) Observatory. EPCs and metered energy use were converted to primary energy use intensity (PEUI) to provide a comparison of the same quantity for the first time. We show that EPCs predict significantly more energy use than metered in homes in Great Britain. EPC bands A and B show no statistically significant difference, but all other bands show a significant gap which increases as EPC rating worsens. The PEUI gap widens from −26 kWh/yr/m2 (−8%) for band C to −276 kWh/y/m2 (−48%) for bands F and G. Unlike previous research, we show that the difference persists in homes matching the EPC-model assumptions regarding occupancy, thermostat set-point and whole-home heating; suggesting that occupant behaviour is unlikely to fully explain the discrepancy. EPCs are a core tool in the residential energy sector, and the gap between EPC-modelled and metered energy use could have a significant impact on policy, research, and industry. Future research should investigate disaggregated components of energy use, the underlying thermal model, and assumptions regarding building characteristics

Domestic Water Demand During Droughts in Temperate Climates: Synthesising Evidence for an Integrated Framework

In the upcoming years, as the population is growing and ageing, as lifestyle changes create the need for more water and as fewer people live in each household, the UK water sector will have to deal with challenges in the provision of adequate water services. Unless critical action is taken, every area in the UK may face a supply-demand gap by the 2080s. Extreme weather events and variations that alter drought and flood frequency add to these pressures. However, little evidence is available about householders’ response to drought and there are few if any studies incorporating this evidence into models of demand forecasting. The present work lays the groundwork for modelling domestic water demand response under drought conditions in temperate climates. After discussing the current literature on estimating and forecasting domestic water consumption under both ‘normal’ and drought conditions, this paper identifies the limited ability of current domestic demand forecasting techniques to include the many different and evolving factors affecting domestic consumption and it stresses the need for the inclusion of inter and intra household factors as well as water use practices in future demand forecasting models