Energy efficiency helps Australian water authorities meet their clean energy goals
Understanding the challenges in the water and wastewater sectors, and identifying the ways to overcome them, means continuing to support water security for all Australians in the most sustainable way. This allows us to uphold our commitment to support water authorities in meeting their clean energy goals.
Water authorities, suppliers and wastewater treatment plants are facing major problems related to escalating costs of electricity in operation. This is being recognised across all water and wastewater pumping, treatment, distribution and discharge activities.
It is worth considering the economics of water and wastewater processing. These sectors are currently very energy-intensive, consuming approximately 4% of the world’s total electricity. High energy consumption raises costs. On average, energy costs make up 45% of the cost of clean water.
Therefore, making water and wastewater processing more energy efficient is key to extending these necessities to more people. At the same time, lower energy use reduces the sector’s carbon footprint and operating costs — everyone benefits.
Opportunities for efficiency
Every process in the sector — from water treatment to transportation, wastewater treatment and desalination — relies on pumping. Fortunately, technology is available that significantly reduces the amount of electricity the pump’s motor requires to deliver the same output.
Both existing and new motors can be fitted with a variable speed drive (VSD). This increases energy efficiency by adjusting a motor’s speed and torque to precisely meet the requirements of the process.
Without a drive, a motor runs at full speed all the time and flow speed is controlled by throttling — that’s like driving a car by keeping one foot on the accelerator and using the brakes to control the speed. With a drive, the motor runs exactly as fast as necessary, usually well below full speed. This enables significant energy efficiency gains — often up to 30% and sometimes even more.
Water and wastewater facilities can also improve their energy efficiency by selecting the most efficient motors. Many countries use the motor efficiency classes set out by the International Electrotechnical Commission (IEC). These classes range from IE1 to IE5. Each increase in IE number, such as from IE3 to IE5, represents a 20% decrease in energy losses, meaning that the motor is more efficient.
Synchronous reluctance (SynRM) motors technology takes efficiency further by achieving IE5 efficiency. They are designed to work as a package solution with VSDs and are significantly more efficient than older motors. For example, replacing an existing IE2 motor with a SynRM motor-drive package delivers up to 50% lower energy losses.
ABB’s efficient motors are designed to be drop-in replacements for older models, so upgrading is usually straightforward. Furthermore, the energy savings will deliver a rapid return on investment. Typically, in months rather than years.
Efficient wastewater treatment in action
In Australia, the operators at a sewage treatment plant in Sydney, New South Wales, aimed to improve their facility’s efficiency to reduce its carbon emissions. They identified the pumps as the best opportunity to reduce electricity use and replaced their existing motors with IE5 SynRM motor-drive packages.
During the renovation, they also improved the pumps’ impeller geometry to improve their mechanical efficiency. The plant still cleans 108,000 cubic meters of wastewater every day, but now it uses 40% less energy.
In greater Melbourne, Victoria, a water pumping and treatment facility is responsible for softening the potable water. The process requires energy-intensive compressors, but the facility powers them using IE5 SynRM motors paired with VSDs. Combined with other energy saving measures, the plant anticipates it will cut its energy use by at least 32% in just one year.
Energy efficiency is an essential step
As the cost of electricity to run plants continues to rise, more effort is being applied to find out where this can be reduced. Regulatory bodies are also implementing more conditions around sustainability to encourage water authorities and treatment plants to become more conscious of reducing energy consumption to lessen environmental impact.
Urbanisation is placing increased demands on aging, energy-intensive infrastructure, including costs associated with system maintenance and repairs. Water is a scarce resource and climate change is adding to the urgency of ensuring water systems work efficiently.
Rory Paltridge, Division Manager for Motors at ABB Australia said, “Implementing already available energy-efficient technologies in these applications will ensure we meet the future needs of a sustainable world, addressing the global water crisis and energy-related challenges.”
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