Replacing old engines with new technology

Gold Fields were looking to retire their bank of diesel generators at the Granny Smith gold mine in Laverton. We’d been trialling gas engines over the previous 18 months. A new gas extension was being built nearby. A need plus a new and better technology, plus an accessible fuel source? It was the perfect alignment of time and opportunity.

We proposed a 22 MV gas power station, with fuel drawn from the new gas extension, powered by our new gas-fired Osprey engines. Ultimately, this meant Gold Fields could make significant cost savings while reducing their carbon footprint at the same time.

We had been trailing larger gas engines over the previous 18 months and these were chosen in favour of the standard QSK60 generators. We proposed using modified high efficiency gas-fuelled Osprey engines in 20 foot containers, which meant we were able to offer savings in fuel costs. The smaller containers also create a smaller environmental footprint compared to competitors, who tend to provide equipment in 40 feet containers, which are more expensive to transport.

Aggreko has more efficient Ospreys than anywhere else in the world and incorporated further technology to improve reduction of gas pressure to offset the cooling down process. A heat recovery system replaces the electric heaters. We are taking the heat from the Osprey jackets and using it to heat the gas. This represents a large cost saving for Gold Fields.

The project was initially constrained by the high pressure of the gas, which was at 90 Bars. Our ability to build a high pressure reduction facility meant we could reduce the construction time and get the new plant commissioned quickly, thereby reducing operational costs.

The new power station will also reduce the mine’s carbon dioxide emissions by approximately 80,000 tonnes over six years, and enable Gold Fields to trade carbon credits with the Australian Government’s Emission Reduction Fund.