Evolution of Granny Smith Mine's Power System

Our efficient, innovative and scalable microgrid supplies power for Gold Fields' Granny Smith mine, located in Laverton, Western Australia.  The flexible power plant helps reduce fuel consumption by 10-13% for the site - which equates to 2,000 less cars on the road.

Read on to learn more about the long-term partnership between Gold Fields and Aggreko and understand the story behind the evolution of Granny Smith mine's power system from diesel to a future-proof hybrid system.

 

The Granny Smith Mine is an underground gold mining operation located 740km northeast of Perth, Western Australia. Operated by Gold Fields, the deposit was discovered in 1979 and in 1989 mining commenced on site with the first gold being poured the year after.

Currently, Wallaby is the operation’s active mine, with mining administration and maintenance located nearby. The annual production of the Wallaby mine is in-excess of 250,000 ounces per year.

Back in 2016, Gold Fields were looking to retire their 17.9MW bank of diesel generators at the Granny Smith gold mine in Laverton. As well as this, a new gas extension was also being built nearby. 

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

Our containerised gas generators built into 20-foot containers not only provide fuel savings to our clients but also have a smaller environmental footprint over competitors, who use larger units that are more expensive to transport and take up more real estate.

For the one-of-a-kind power station, we also installed a high pressure gas conditioning infrastructure and heat recovery system which optimise power station efficiency and reduce gas pressure from the gas network.

At the time of the construction, the new power station was expected to 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.

Exactly 2 years after 2016 project, Aggreko started work with Gold Fields to introduce renewables on site.

The plan was to provide 7.3MW of solar power generation, as well as a 2MW/1MWh battery system, to be integrated with the existing gas supply as a hybrid power station - under one contract and with no capital outlay.

“Our mining clients have faced a challenging marketplace and power generation is a significant proportion of operating costs. Our global capability offers additional flexibility which reduces investment and operational risk,” said George Whyte, Managing Director of Aggreko AusPac. “Aggreko’s focus is on fuel efficiency and reliability in line with the power demand over the life of the mine,” Mr Whyte said.

Stuart Mathews, Executive Vice President Australasia at Gold Fields, said that in addition to the cost efficiency and reliability benefits of the new hybrid power station, the upgrade reflected Gold Fields’ commitment to the increased usage of renewable and low-carbon energy sources throughout the Group. Gold Fields is committed to using renewables for at least 20% of total life-of-mine power requirements in new projects.

For the mine operator, the integration of renewables in the energy mix was a demonstration of their ongoing commitment to both environmental sustainability and innovation at its operations. The proposed new measures would reduce company's carbon footprint by utilising the latest hybrid energy technologies.

The new hybrid power system, combined with expansion of the existing thermal power station will meet the increased daily power needs of 24.2MW, with 8MW allocated to the Wallaby underground mine and the remaining 12 power for the processing plant, associated facilities and the mine accomodation camp.

In 2019, Aggreko installed one of the world’s largest renewable energy microgrids at the Granny Smith mine site. Powered by more than 7.7MWp of solar and backed up by a 2MW/1MWh battery system. Aggreko engineered, produced, constructed and managed the build of the solar power system.

We installed 23,040 solar panels covering 22.68 hectares, which is the equivalent of 181 Olympic Sized Swimming pools, 22 International Rugby Fields or 11 Melbourne Cricket Grounds.

The 2MW / 1MWh battery storage component offers consistency and reliability of the system and provides spinning reserve, ramp rate control, frequency and voltage regulation, fuel displacement and emissions reduction. 

Construction of the renewable energy system commenced in May 2019 and on completion it became one of the world’s largest hybrid off-grid microgrids. Integrated with Aggreko’s existing natural gas power generation this hybrid system is an ideal example of sustainable gold mining without compromising on reliability. 

The solar-plus-battery system was projected to reduce fuel consumption by 10-13% – the equivalent of removing 2,000 cars from the road – and produce about 18 GWh of clean energy per year.

In 2020, we completed installation of the solar PV and battery storage system. The solar PV reduces the need to run thermal generators at the mine, while the battery plant provides essential services such as PV ramp rate control and transient voltage/frequency support. The assets are being managed by Aggreko’s control software platform which rapidly deploys automated responses to avoid issues and predicts future problems.

The mega solar and battery power facility is fully integrated with Aggreko’s existing 27.3 MW natural gas generation and complements Gold Fields’ suite of on-site energy solutions across other operations.

Aggreko’s AusPac Managing Director, George Whyte, said: “Demand for decentralised energy solutions has skyrocketed over the past few years as companies look past the grid for power solutions to help them meet their unique needs. The hybrid assets we’ve delivered for the Granny Smith mine will help Gold Fields reduce operating costs and carbon emissions with the flexibility and capital expenditure savings that comes with rental solutions.”

In total, the battery storage and solar power assets produce around 18 GWh of energy every year with carbon emissions at the mine expected to be reduced by approximately 9,500 tCO2e.

The mining industry accounts for over 6% of global energy consumption, and miners have the great challenge of reducing their emissions in line with the Paris Agreement, as well as their own commitments to net-zero emission targets by 2030 and 2050. Aggreko is supporting the industry, as a major growth area for its business, being at the forefront of energy transition.  

Hybrid power solutions play a vital role in moving to more sustainable practices in operation of remote mines. With the existing cost-effective and reliable technologies, they are the first step or the industry in achieving Net Zero by 2050.

Learn more about the new and emerging technologies which will assist the industry in reaching this ambitious target.