Water and energy futures for Melbourne: implications of land use, water use, and water supply strategy S. J. Kenway, G. M. Turner, S. Cook and T. Baynes ABSTRACT This paper quanties the effect of three policy levels on the water and energy futures of Melbourne, Australia. During a time of severe water shortages attributed to climate change, water strategies lacked consideration of energy consequences. Modeling, guided by urban metabolism theory, demonstrated that a compact urban form, reduced water consumption by 90 GL/a, compared with a sprawling city, and had greater water conservation impact than simulated demand management measures. Household water conservation, coupled with increased use of solar hot water systems, reduced grid energy use by some 30 PJ/a. Desalination, tripled water supply energy demand, growing to a total of 4.5 PJ/a, by 2045. While the increase is less than 1% of total Melbourne urban energy use, it contributes to a substantial increase in the energy bill for urban water provision. Importantly, the energy impact could be offset through demand management measures. Recommendations for the combined management of water and energy include improving energy characterization of the urban water cycle; impact-evaluation of regional plans; using total urban water and energy balances in analysis to provide context; and developing reporting mechanisms and indicators to help improve baseline data across the water and energy systems. S. J. Kenway (corresponding author) The University of Queensland, Advanced Water Management Centre, Gehrmann Building, Research Road, St Lucia, Brisbane, Australia E-mail: s.kenway@uq.edu.au G. M. Turner CSIRO Ecosystem Sciences, Clunies Ross St, Black Mountain, Canberra, ACT, 2601, Australia S. Cook CSIRO Land and Water, Highett, Melbourne 3190, Australia T. Baynes CSIRO Ecosystem Sciences, 14 Julius Ave North Ryde, NSW 2113, Australia Key words | energy, future cities, land use, urban metabolism, water INTRODUCTION Between 2002 and 2009, many Australian cities faced an extended period of below average rainfall leading to cri- tically low water storage levels. Future projections of climate change suggest exacerbated severity of dry periods (Howe et al. ; Jones & Durack ), with up to a 25% reduction in catchment inows for some cities (WSAA ). Australian cities have responded to this period of water stress by developing strategic water plans that have the purpose of providing water security in the face of uncertain rainfall and inows, and increasing demand being driven by population growth (Rijke et al. ). Strategic water plans were underpinned by the adoption of rainfall independent water sources, most signicantly desalination of seawater by reverse osmosis, together with a focus on water efciency measures and demand reduction (Donald & Seeger ). However, the development of water plans gave rela- tively little consideration to the energy implications of adaption strategies. Australia had not ratied the Kyoto Pro- tocol at the time and had no rm long-term greenhouse gas mitigation target. It was not easy, or even possible, to see how the actions of solvingone problem in the system (such as water), could lead to inuences elsewhere (such as energy). The inuence of longer-term processes such as land use planning or urban form were even further from the discussion, as was the energy implications of water con- servation. Since 2007, the rapid anticipated growth of energy demand for urban water provision in Australia, due to adoption of rainfall independent water sources, has become increasingly clear (Kenway et al. b; Chanan et al. ; Hall et al. ). It has been identied that as water and energy are intrinsically connected, there is need to develop complementary long-term strategies for water 163 © IWA Publishing 2014 Journal of Water and Climate Change | 05.2 | 2014 doi: 10.2166/wcc.2013.188 Downloaded from https://iwaponline.com/jwcc/article-pdf/5/2/163/375002/163.pdf by guest on 13 June 2020