|dc.description.abstract||Eskom, the sole supplier of electricity in South Africa is facing an energy crisis. This
is due to the steady increase in demand for electricity in South Africa. Low electricity
prices in South Africa have helped the energy intensive industries of South Africa to
be more competitive. Unfortunately this has resulted in poor energy efficiency
practices and has hampered incentives to save energy.
To address this problem, Eskom initiated a Demand Side Management (DSM)
programme. DSM is beneficial to both Eskom and the client. However, due to the
high cost of implementing such projects, it is feasible to implement it only on sites
where the load shift potential is high enough for Eskom to benefit. The mining
industry has been targeted for DSM programmes. This is due to the existence of a
large mining sector in South Africa and to its energy intensive nature.
Most mining operations require large amounts of water which is used to cool the
underground environment and so ensure productivity and the safety of the workers.
Due to the large amounts of water needed for mining, the electricity usage of these
pumping systems is very high. If the use of this electricity can be optimised by
implementing DSM principles, this will result in the long term savings of costs for the
The majority of pumping systems found on mines are single shaft systems.
Individually these systems have a very high DSM potential. However, if multiple
shaft systems can be used for DSM, the benefits will be far greater. Furthermore,
combining several sites with an interconnected water pumping system will increase
the potential for DSM and enable sites where individually the potential is too low to
be feasible for a DSM project to raise their potential. This will result in more sites
where DSM projects can be implemented and more clients who can benefit from the
The purpose of this study is to investigate and implement a DSM project on an
intricate multi-shaft mine pumping system which will be controlled from a single
point. The project required a detailed investigation of the pumping systems on each
shaft and how the water system is interlinked between the shafts. This project was
carried out on Beatrix Mine Shafts 1, 2 and 3. The pumping systems were analysed
and simulated according to the specific constraints and requirements that were
specified by the mine.
During the investigation and implementation of this project, possible efficiency
improvements on certain pump stations were discovered and implemented. The
improvements enabled both an increase in water flow to the surface and a decrease in
power consumption. Due to this load reduction, the savings achieved were higher than
those found in most load shifting projects.
Moreover, additional infrastructures were installed to ensure communication between
pumping systems. Once the simulation and optimisation of the control system was
completed, the pumping system network was automated. The load shift resulted in a ±
3.5 MW shift in the morning peak demand period and a ± 6.0 MW shift in the evening
peak demand period.
This load shift has resulted in an average cost saving of R 80 000 per month during
summer tariff period, and R 300 000 per month during winter tariff period. This
saving result was calculated by taking load reduction into account. This project has shown that a DSM project can be implemented successfully, given the necessary
historical data and expertise, on a pumping system that is interconnected between