Copper miners use large amounts of energy. During the metallurgical process the molten grade copper that is drawn from the furnace is aided by the blower air. The energy is used for the converter blowers that provide medium pressure air to the copper convertors. At a copper mine in Africa, the exothermic reaction consumes approx. 3.6MW of electricity 24/7 and the operator believed this process was very efficient.
The operating cost of the system was US$6,500,000 per year. Electricity costs for the converter blowers was approx. US$1,500,000 per year and a further US$5,000,000 of fuel (8 million liters) and coal (10,000 tonnes) consumption.
The task was to identify and implement a change to the operating method that would reduce the energy waste in the system. During the review of the system, a fault was revealed in the coal system that had been present for over 15 years (wasting 45,000 tonnes of coal and 45 million liters of fuel).
Through the implementation and diagnosis of several energy saving interventions, the following was achieved.
As a result of the review and implementation, 26,000 tonnes of greenhouse gas emissions had been removed from the operations each year.
A total of 8.8MW (combined electricity, coal and fuel) was saved without the need for further capital investment. And more importantly, the project had a positive cashflow with a Net Present Value (NPV) of US$22,000,000 at 12% discount rate.
Not all energy waste opportunities require significant upfront capital. You just need the right people in the room to help identify the problem and implement the solution.