Dr Steven Kenway is the Research Group Leader, Water-Energy-Carbon at The University of Queensland. He has over 25 year’s research, industry and consulting experience at CSIRO, Brisbane Water, Sydney Water, and government. His work focuses on the water-energy nexus and urban water management. Steven is a Fulbright and Australian Research Council Fellow. He is an International Water Association (IWA) task-force leader for water-energy frameworks, a Management Board member of the IWA Specialist Group for the specialist group in Sustainable Water management, and a Steering Committee member for Cities of the Future.
In Hot Water – Understanding the Links between Households, Industry, and Water and Energy Utilities
By Steven Kenway, Amanda Binks, Julijana Bors, Francis Pamminger, Paul Lant, Brian Head
In Melbourne, up to half of all household energy use is water-related, mostly from hot water used in showers and clothes-washers, as well as from efficiency losses, according to research. In fact, urban water directly and indirectly influences 10 percent of Australia’s primary energy use, primarily from water heating in homes and industry. By far the biggest opportunity to reduce the energy use of urban systems involves understanding how water utilities interact with households and industry.
This article describes a project focussed on understanding the links between water and energy in households. This knowledge helps determine if the solutions are solving problems (for example, through efficiency measures) or if they are simply shifting a water problem to an energy problem. Water Services Association of Australia and the Commonwealth Scientific and Industrial Research Organisation forecast that energy expenditure for urban water will rapidly grow over the next 25 years. This work helps manage this risk. The Melbourne metropolitan water industry spent about $30m on electricity in 2014, and is expected to spend between $50m – $130m by 2030. One of the challenges for the water industry will be to offset this increase without increasing customers’ water bills.
Small changes to water management can have a surprisingly large impact on energy use for the household consumer. For example, a 10 percent reduction in the frequency, duration, or flow-rate of water for showers would reduce household energy use by 0.5 – 1.0 kilowatt hour (kWh) per household per day. This equals about one percent of total household energy use in Melbourne. The research indicates that water-related energy usage ranges from 5–20 kilowatt hour per household per day. [For perspective, 10 kWh is equivalent to 37 efficient light bulbs (11-watt) operating for an entire day.] The range of usage between individual households can vary dramatically and may be indicative of different household technologies, fittings, or behaviour patterns. The detailed results of this project could be used to help households identify options to reduce their energy use and their bills.
Water and energy utilities have understood and managed their direct energy use for some time. While improvements in the efficiency of water and wastewater treatment plants and pump stations are possible and important, we now know that this is just a small part of the overall puzzle of energy-efficient urban water systems. Houses use about ten times more energy to heat water than a water utility uses to provide water and wastewater services to that home. Consequently, knowledge of water-energy links in households gives both the water and energy sector utilities many other possibilities to help reduce energy use and costs.
By innovatively mapping water temperature data collected from water quality testing programs, we have shown how variations in water temperature delivered in Melbourne influences household energy use differently in different regions. In addition to managing water quality and pressure, the water utility of the future may also need to find ways to manage water supply temperatures, in order to provide greater value and meet their customers’ needs.
Another option to help consumers reduce costs and energy use is to encourage manufacturers to build appliances that can connect to both hot and cold water sources. For example, if clothes-washers and dishwashers can use warm water from renewable sources (such as solar power or heat pumps) then household costs along with greenhouse gas emissions can be reduced. There is also an opportunity for manufacturers and developers to coordinate efficiencies between appliances to reduce total energy use and water bills.
The study has also identified policy options to progress improved management of water-related energy including integrated metering, improved labelling, and setting State targets.
Funding from the Smart Water Fund and Australian Research Council are acknowledged.
Outputs from this project are available via the Smart Water Fund Knowledge Hub.