Mining the gap in long-term residential water and electricity conservation

Abstract

Climate change and economic development provide a strong rationale for urban water and electricity conservation. Although behavioral and technological factors link short-term conservation of both resources, their long-term residential consumption trends have diverged across industrialized nations: from 1990 to 2010, per capita water use decreased, while per capita electricity use increased. This long-term ‘conservation gap’ has not generally been examined but it presents an opportunity to better understand what drives persistent residential conservation. Here, we analyze 2002–2012 water and electricity consumption from 38 000 California residences to characterize the conservation gap and its socio-economic determinants. Aggregate per-residence consumption figures show a 19% decline in water use—concentrated in the 2007–2009 drought—and an 8% increase in electricity use—coinciding with early 2000s economic growth. We find no meaningful socio-economic variation in micro-scale consumption trends across the study area but the ‘gap’ tendency is greater in residences with low customer-turnover, suggesting that widespread factors—including the proliferation of consumer electronics and small appliances—drove electricity use increases. Long-term water conservation was also widespread, suggesting that droughts provide immediate, locally-driven conservation imperatives that have been successfully leveraged for long-term water savings.Similar episodes were not generally available to electricity policy makers during the study period, but extreme climate events could drive energy efficiency campaigns in the future.