|dc.description.abstract||South Africa is experiencing serious electricity supply problems. A major concern is
the high peak electricity demands between 18:00 and 20:00. This peak is primarily
caused by the growing residential sector. Unfortunately, changing people's behaviour
to reduce the evening energy peak is difficult. An easier approach will be to focus on
other sectors such as the industrial and mining sectors.
South African mines contribute 18% of the country's electricity consumption. Of the
total mining electricity bill 40% is consumed by water pumping systems. Manual load
shifting is attempted on approximately 15% of these pumping systems. The results are
not sustainable due to maintenance problems and system complexities.
By automating, simulating, optimising and controlling the pumping systems of deep
level mines, sustainable load shift can be achieved. This will also reduce the running
cost of mine water pumping system due to time based electricity pricing.
With this research a novel solution is presented. This unique automated tool
simulates, optimises, schedules and controls any pumping configuration in a unique
integrated fashion. The new system was tested in 13 case studies, involving a wide
variety in terms of layout, size, and equipment types. More than 39 MW of load was
consistently shifted out of the evening peak. This resulted in cost savings of more than
R 5,7 million per year for the mines involved in the case studies.
This system also has other benefits. Automated systems require fewer personnel such
as pump attendants, leading to more savings. The system also provides better
safeguard against the risk of flooding, and faster training of new control room
personnel. The benefits for ESCOs are fast and accurate predictions on the savings
potential of specific pump configurations.
These and other benefits indicate that the new control system should be rolled out on
all large pumping systems.||