Active optimisation of water treatment and pumping scheduling to maximise solar energy use and minimise electricity network peak demands

The process of drawing water from the Proserpine River, treating and finally pumping clean drinking water to the people of Bowen requires a great amount of electrical energy for which the Whitsunday Regional Council must foot the bill. Solar panels have helped to reduce electrical usage during the day; however, the plant and process have not been optimised yet to maximise the usage of solar power. This is the goal of this project, and more specifically to better fit the plant’s electricity usage schedule to the daily and hourly solar irradiance. A proposition of an ‘autopilot’ process was developed for water treatment plant operators to use as a background tool, while they focus on other processes within the treatment plant. This is facilitated through software tabulation of all the possible high-lift pump power values defined by the intersection of the hydraulic system curve and pump curve. By utilising the available solar power, and the closest possible pump speed (r.p.m) for matched power consumption, pumps can ramp up and down within 5 – 60-minute update intervals defined by the operator. Other electrical loads are pre-loaded onto a comma separated value (CSV) file, which is then imported and shown to visually subtract from the available solar power. Tank severity (urgency) levels are described based on seasonal conditions set by the operator to which pump speed (r.p.m) is set to match accordingly. In addition, the option to reserve some power from the available solar power can be set later when introducing battery storage systems. Simulating the option to eliminate night-time operations to minimise costs and grid power usage becomes a possibility without affecting the plant in real time. Options to expand the process and implement the knowledge at other plants is discussed with the ability to implement additional pumps and other parameters.