Global mining giant Rio Tinto has unveiled plans for a large solar farm to feed its new $2.6 billion Koodaideri iron ore mine in Western Australia's Pilbara region.

Key points: Mining giant Rio Tinto says a plan to power a new mine with solar energy is the first step in a push towards decarbonisation

Mining giant Rio Tinto says a plan to power a new mine with solar energy is the first step in a push towards decarbonisation The company says the reduction in emissions will be the equivalent of taking 28,000 cars off the road

The company says the reduction in emissions will be the equivalent of taking 28,000 cars off the road A sustainability expert says it's a small but welcome step driven by heightened concern about climate change

The 34-megawatt plant near Newman will be the company's first, and is set to accompany a lithium-ion battery system in Tom Price that will help power the company's entire Pilbara network.

Rio Tinto iron ore chief executive Chris Salisbury said the $144 million (US$98m) project was a key plank in the miner's bid to reduce emissions — but it also made financial sense.

"Apart from reducing emissions, obviously these projects have a financial return," he said.

"So it is possible to reduce emissions at the same time as ensuring we remain an efficient operation as well."

'Road map for decarbonisation'

Rio Tinto has also announced that it will release plans for future emissions reduction targets.

"This will really set out our road map for substantial decarbonisation in the business," Mr Salisbury said.

"This [Pilbara plant] is really an important first step towards that.

"We are investigating additional renewable energy options in the Pilbara, as well as other opportunities to reduce emissions across our entire global portfolio, building on the 43 per cent reduction in absolute greenhouse gas emissions since 2008."

The energy system is expected to reduce the company's carbon dioxide emissions by 90,000 tonnes — the equivalent, according to Mr Salisbury, of "taking about 28,000 cars off the road."

Rio Tinto's total Pilbara emissions in 2018 were 3.2 million tonnes.

Autonomous haulage tucks at Rio Tinto's West Angelas iron ore mine in the Pilbara. ( Supplied: Rio Tinto/Christian Sprogoe Photography )

Sign of 'apocalyptic' times

Experts applauded Rio Tinto's move, but said the emissions reduction was small compared with the miner's overall carbon footprint.

Peter Newman, a professor in sustainability at Curtin University and lead Intergovernmental Panel on Climate Change author.

"So yeah, 90,000 — it's a small step, but an important one," said Peter Newman, a professor in sustainability at Curtin University and lead Intergovernmental Panel on Climate Change author.

Curtin University climate scientist Peter Newman. ( ABC News: Laura Gartry )

"It's 34 megawatts out of a total power system in the Pilbara of about 450 megawatts on the grid system and another 1200 megawatts from the mining companies, so it's a small step, but a welcome one."

He said the horrific bushfires had put climate change on the political agenda.

"I think the 2020s came with an apocalyptic bang with the bushfires and an awareness that the Australian public were no longer just saying 'we want some action,'" Dr Newman said.

"It was appalling what we saw happening, and the extremes in weather are now clearly on the political agenda.

"A group like Rio picks up on this very quickly … and we will look to them in the future and say 'well done, gee it would have been nice if you'd done it ten years ago.'"

'A little late'

Nevertheless, Dr Newman said the company was showing "genuine leadership" on cutting emissions.

"It's a little bit late coming, because really this kind of [solar] technology … and wind have been pretty much cost-effective for the past 10 years," he said.

"Only now replacing gas cheaper, but nevertheless it is a very good step."

The $2.6 billion Koodaideri mine, located about 110km north west of Newman, was approved last November and first production is due by the end of next year.

It is expected to produce 43m tonnes of iron ore annually.

The solar farm will consist of 100,000 solar photovoltaic panels over 105 hectares, and is expected to supply all of the mine's electricity demand during peak solar power generation times, and about two thirds of the mine's average electricity demand.

Construction is expected to begin later this year, subject to government approvals, and is due to be completed in 2021.