Water and Energy Efficiency: Transmission Operations Optimizer (TOO) City of Toronto Water Supply

This paper describes the implementation of an automatic control system based on operational optimization, for city of Toronto and York Region Water Transmission System. The new automation system has been in operation since November 2015. The water supply system, serving a population of 3.4 million, is the largest in Canada and one of the largest in North America. The system consists of treated water pumping at four filtration plants, 18 pumping stations, 15 reservoirs/tanks, 126 pumps (up to 1,865 kW (2,500 hp)), and approximately 500 km (310 miles) of large transmission mains. While the city of Toronto and the region of York provide the water delivery/service requirements in a cost effective and uninterrupted manner, the complexity of the water system and the volatility and complex structure of the energy rates, present opportunities for benefitting from automation and further optimizing operations. As part of the new automation process, the transmission operations optimizer (TOO) minimizes energy used and cost of energy, while ensuring fundamental service delivery standards including pressure, flow, and storage are met. Pre-set minimum (critical) storage levels are not violated. ‘Optimal’ automatic control strategies are achieved for different seasonal, weekday/weekend demand patterns, as well as when abnormal events occur such as a pumping station or filtration plant being taken out-of-service. TOO involves water consumption/demand prediction, energy rate prediction, hydraulic modeling, mathematical optimization, analytical algorithms, data integration and on-line monitoring of system performance, and energy spot-market rate.