“There were a number of compelling statistics which led us to this research”, said Dr Michael Storey, Research Direction and Value Manager at Sydney Water.
“Temperatures are 6-10°C higher in western Sydney during the summer period than they are in the east and there can be up to three times as many deaths in western Sydney during heat waves than there are in eastern Sydney. Energy consumption for cooling Western Sydney is up to 100% higher than in the eastern zones of the city. Peak Electricity Demand increases by almost 100% when temperature increases from 20°C to 40°C.”
Dr Storey added that effective cooling of western Sydney by implementing the solutions outlined in the Cooling Western Sydney research could result in:
- Reduced peak ambient temperatures by 2.5°C
- An estimated energy saving of 1726 gigawatt hours (GWh) per year = 1.726 Billion kilowatt hours. The average Australian house uses 6,570 kilowatt hours (KWh) per year. This saving is the equivalent used to power around 262,000 homes for a year.
- A 9% drop in peak electricity demand, which equates to almost one million tons of avoided CO2 emissions, enough to create the equivalent of removing over 200,000 average sized cars from the roads each year and significant savings on power bills.
- A reduction in the heat related mortality rate by up to 90% in western Sydney
The study investigated the role of water and related infrastructure, greening as well as building materials on cooling western Sydney.
It has challenged conventional thinking around mitigating urban heat, including the way we look at the built environment, energy demand, public health and ‘greening’ cities.
“We must take a multi-faceted approach that includes hard surfaces such as roofs and pavements”, said UNSW Professor Mat Santamouris.
“The solution is not just about planting trees, which seems to be the commonly held view.
“Trees create a cooling effect through a process called evapotranspiration, where water stored in the tree evaporates through the leaves during hot temperatures. However, when trees are subjected to extreme heat stress, they go into survival mode to conserve water to keep themselves cool.
“This means that we can’t rely solely on urban green spaces as a means of cooling the city in extreme temperatures.
“While greenery does have a cooling effect, the study shows the most effective urban heat mitigation technologies use a combination of water based technologies including fountains in conjunction with cool material technologies such as cool roofs and pavements. Integrating these new and advanced technologies into urban design can greatly reduce the impact of urban heat and assist in cooling Western Sydney.
“These solutions are the best way to enhance the liveability of western Sydney and will deliver greater economic, social and environmental benefits”, said Professor Santamouris.
Dr Storey added, “this is a whole-of-Sydney issue. Cooling western Sydney means cooling eastern Sydney. We must think locally but act globally.
“There are large geographical and meteorological forces at play in western Sydney. On one side we have the large western deserts and desert winds, and on the other the Pacific Ocean and eastern ocean breezes. Trapped in the middle and bordered by the Blue Mountains is western Sydney, which can be subjected to extreme temperatures in summer time because the area receives little respite from ocean breezes and southerly winds.
“As Sydney is set to experience more prolonged summer heatwaves in future due to a changing climate, it will be critical for temperature peaks to be reduced to improve the thermal comfort for people living in western Sydney.
“The careful selection of water-based technologies and building materials can achieve a decrease of up to 4.5º C, which will take the ‘tops’ off the peak temperatures in extreme heatwave conditions in Sydney’s west”, said Dr Storey.
- First published by Sydney Water
Image: Sydney Water
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