PERTH (miningweekly.com) – The Gruyere joint venture (JV) partners have appointed energy infrastructure provider APA Group to install a renewable energy hybrid microgrid at the gold mine in Western Australia, increasing the mine’s power capacity by 45% to enable plant throughput to reach 10-million tonnes a year.

In the first phase of works, APA will expand the Gruyere power station with the installation of a twelfth reciprocating gas-fired engine. Work is currently underway on this expansion, which is expected to be commissioned in mid-2021.

In the second phase, APA will build, own and operate a 13 MWp solar farm backed up by a 4.4 MW/4.4 MWh battery energy storage system. APA’s microgrid will use a hybrid control system that combines cloud and weather forecasting, battery control and the existing reciprocating engine control systems to optimise efficiency and maximise the use of renewable generation.

The Gruyere microgrid is expected to be commissioned in the fourth quarter of 2021.

JV partners Gold Fields and Gold Road Resources on Tuesday said that APA had been contracted to install the new capacity under the existing electricity supply agreement, which runs until November 2033.

The cost of the Phase 1 and Phase 2 expansion is forecast to reach between A$32-million and A$38-million, with the two phases expected to increase installed capacity at Gruyere to 64 MW.

The microgrid is expected to reduce carbon emissions by some 16 000 t/y of carbon dioxide equivalent, and will generate power supply savings of some 5%, at current gas market prices. The increased power supply will also ameliorate gas power generation capacity constraints, including the derating of gas engine performance at high ambient temperature.

“Gold Road is proud to be part of this green energy initiative. We have long stated our intention to be an environmental, social and governance leader, and this initiative follows on from the recent commissioning of a solar and battery power solution at our Yamarna exploration facility,” said Gold Road MD and CEO Duncan Gibbs.

“The power expansion at Gruyere provides an elegant technical solution that reduces greenhouse gas emissions, decreases costs and enables an increase in plant capacity to a targeted ten-million tonnes a year from the current nameplate design of 8.2-million tonnes a year.

“This will not only see increased annual cash flow generation for the business, but will help drive additional unit cost reductions as Gruyere is further defined as a tier one, low cost and long life gold producer.”

Gold Fields executive VP Stuart Mathews said that the installation of renewables as part of the power solution at Gruyere reflected the company’s strategic objective to strengthen energy security, optimise energy cost and reduce its carbon footprint through the adoption of innovative new technologies.

“The success of the recently completed renewable energy projects at our Agnew and Granny Smith mines has given Gold Fields the confidence to ramp up use of these technologies across our global operations,” said Mathews.