Coober Pedy powered by 100 per cent renewables – most of the time

The power company that has installed the ground-breaking hybrid renewable energy system at the famous outback opal mining town of Coober Pedy in South Australia is claiming a world-record for the amount of time the local grid has been operating at 100 per cent renewables.

EDL has been operating the plant, a mix of wind, solar, batteries, flywheels, diesel and resistors, since 2017 – and it says that the average share of renewables in the town’s electricity supply since then has been 70 per cent.

Even more impressively, for more than half the time it has been running at 100 per cent renewables, with the longest uninterrupted period of 100 per cent renewables being 81 hours, achieved in December last year. And it has been running at 99.9 per cent reliability.

This is important news. For all the talk about 100 per cent renewables, it is quite another thing to actually do it, thanks to the complexity of integrating and optimising all the different components, and sizing them correctly, particularly in remote and off-grid locations.

And, as many experts say, if you can do it on a small grid, then there is no reason at all why it cannot be done on a bigger grid.

The EDL project copped some flack, from some energy analysts and some locals when it was first implemented, because of the high costs involved and the heavy funding from the Australian Renewable Energy Agency, which provided nearly half the upfront cost.

But EDL says the ARENA funding was needed, and is justified. The learning experience from Coober Pedy, and other developments including the newly announced wind, solar and battery project for the Agnew gold mine in South Australia, means that renewables are now considered “business as usual.”

“Fifty per cent renewables will be considered the norm, and 100 per cent renewables will be attainable with more battery storage and hydrogen,” says Todd Gordon, the business development manager, renewables, at EDL.

The set up at Coober Pedy includes 1MW of solar, 4MW of wind, a 1MW/500kWh battery, a 3.9MW diesel generator, 1.7Mv flywheel and a 3MW dynamic resistor.

It is saving 2.1 million litres of diesel a year, and EDL is confident that can be improved.

“It is the first time that level of renewable energy has been delivered at this scale,” Gordon says.

And as technology and experience grows – greater hub heights for wind turbines, better integration of the various technologies, and system optimisation – so will the size of these microgrid applications.

EDL is already looking at how the spilled generation can be captured and used – such as for transport. Hydrogen looms as the likely solution, as it does in many other similar situations.

EDL says the experience at Coober Pedy has paved the way for the newly announced $112 million project at Agnew, which will take the hybrid solution to a new scale , and will be the first major mine to combine wind, solar and batteries.

The combination of an 18MW wind farm, 4MW solar farm and a 13MW/4MWh battery system (BESS), with a 16MW gas engine power station, and back-up diesel,  will cut carbon, and fossil fuel generation by more than 50 per cent. In fact, it will aim for up to 60 per cent share of renewables, with no compromise on reliability or power quality.

Gordon said the support granted by ARENA for Agnew is 80 per cent lower – on a per megawatt basis – than for Coober Pedy. The initial 4MW solar farm – already installed – required no subsidies or third-party funding. The $13 million ARENA support for Agnew is because it is for the first of its kind installation of wind in a hybrid facility for a mine.

“The projects we are looking at now that do not require support, and they will deliver higher margins,” Gordon says. “We have reached an important inflexion point. 50 per cent renewables will become the norm, and 100 per cent renewables is possible.”

And, he notes, many existing mining projects across Australia can be upgraded and hybridised as miners look to lower costs, lower emissions, and get certainty about their energy costs, which can comprise a significant share of their costs.