Energy Efficiency: Mining Sector Can Do Better

Energy Efficiency Mining Sector Can Do Better

William Gould, CEO of Tsebo Energy Solutions

In the last couple of years, the mining industry has faced many challenges, grappling with high operational costs and fluctuating commodity prices, on top of ongoing strike action and wage negotiations.

25 Degrees in Africa talked to William Gould, CEO of Tsebo Energy Solutions about how sustainable energy solutions can assist mines in maximising their bottom line.

According to Gould, roughly 30% of operating costs of mines goes into energy and particularly electrical energy. While many players recognise value in going the efficient route, implementation is often a challenge on its own.

“Mines are very conscious of their energy consumption and have for many years been trying to improve, but most interventions need capital investment and with many competing demands for capital, it often remains a non-core priority,” he says.

In order to make sure that these investments make a real difference, before embarking on any energy initiatives, Gould notes that it is imperative to consider the equation of supply and demand in the mining sector. From the demand side, mines need to look closely at all the individual energy consumption processes and determine what they could and should be doing to lower the amount of energy they require from the energy supply.“You don’t want to be operating an inefficient mine with sustainable resources,” he says. “That is a very expensive exercise.”

According to Gould common practices need to change to move forward and there are some very logical things that can be done, but South Africa lags global markets in some practices. For example, plants that are not maintained uses more energy and by just selecting a high efficiency (IE2) pump over a standard efficiency (IE1) version, mines can achieve large savings when taking into account the lifespan of the pump’s operation. In the ventilation of mines, a lot of efficiencies are already being realized  such as fans that consume 30% less energy than the ones traditionally used.

Once the energy demand is down to its lowest consumption level, it starts becoming sensible to consider renewable sources of energy supply, especially in areas with no existing power infrastructure from a supply authority. In the South African and African context, the high level of irradiance makes solar energy solutions an attractive option with a six to seven hour productive window a day, and in some areas wind is also an abundant natural resource.

“What we are seeing from a global point of view is that opting for photovoltaic solar systems is a very viable opportunity. To run diesel electric plants, it costs around 35 US cents per kilowatt hour, compared to about 10 US cents per kilowatt hour in parts of Southern Africa with developed infrastructure. With solar panels you can generate electricity at around 17 US cents per kilowatt hour,” Gould states.

However, because storing solar power is very expensive, Gould explains that it should predominantly be used as supplement during daylight hours. He suggests using as much as solar energy possible and at least matching the base load with renewable energy, but only when using energy efficient equipment.
Ultimately, for mines to make sensible investments into sustainable business practices that will benefit them in the long run, they need measure their power consumption, understand how they can reduce their consumption profile, and then select proven energy efficient technologies that include renewable sources.

Voltage Optimisation

Excessive supply voltages are quite common in South Africa. The histogram below represents a supply point in Sandton. The Average voltage is 245V, but voltages exceeding 250V are not uncommon.

The Powerstar® product which Tsebo Energy Solutions have the exclusive right to distribute in South Africa is a Voltage Optimisation Unit which reduces the energy demand of most electrical devices.

Resistive loads will draw a reduced current when a lower voltage is applied. In cases where the loads are controlled by thermostats or similar control systems, the load will simply stay on longer until the required energy has been consumed. In these instances, the energy consumed will be the same, but the demand will be reduced. In the case of electric motors, especially those that are not fully loaded, the overall efficiency of the motor will increase if the supply voltage is reduced to the nominal design voltage.

Different types of equipment will respond differently when supplied by a reduced voltage. In an average building, there will be a selection of plant that will consume less energy when the voltage is reduced.

All electrical devices will consume energy and dissipate it in the form of heat/sound/motion. Voltage Optimisation Units are no exception to this rule, they are however extremely efficient in design, and the additional losses introduced are offset by the very significant reduction in electricity demand from the load.

White Paper – Voltage Optimisation

Voltage optimisation system introduced into SA

Tsebo Outsourcing has launched Tsebo Energy Solutions (TES) as an addition to its current suite of outsourced products and services coinciding with the introduction of Powerstar voltage optimisation technology in the South African market. The Powerstar system is currently exported to more than 15 countries, including Ireland, Cyprus, Greece, South Africa, Sri Lanka, Bahrain and Malta This voltage optimisation system delivers significant savings in three areas, namely over-voltage, harmonic contamination and reactive power. TES is equipped to install and maintain the technology. Starting off by assessing the customer’s energy data using a consumption intelligence (CI) system followed by use of a national tariff engine, TES then demonstrates the monthly and long-term savings an intervention would generate.

Contact William Gould, Tsebo Energy Solutions, Tel: 021 595-4355,

Energy trends to watch in 2013

Commercial energy efficiency retrofits:
As we all adjust to a world of higher energy costs, the business case is stronger for projects that deliver ongoing savings in energy consumption, and there is a growing understanding that individual businesses and society as a whole can save money by investing in technology today.

Turning waste into power:
New technologies are emerging that create value out of what some of us deem to be waste. A great example is the practice of turning municipal waste into gas that can be used as energy. A number of companies in the USA are actively pushing marketing these solutions today.

Grid energy storage:
Energy storage technology continues to attract R&D spend and investment. We will continue to hear about more energy storage projects that are adjacent to renewable energy installations, which should have the effect of balancing loads.