“Ship’s crew and its cartogropher:” AEMO maps out priorities for 100 pct renewable grid

“Micro-grids have been proven to operate successfully for long periods without the support of synchronous generating units,” the document says.

“However, to AEMO’s knowledge, no gigawatt-scale power system has achieved this without interconnection to other large systems.

“This presents a significant challenge for Australia, as the pace of transition is rapidly taking the NEM toward periods where sufficient renewable generation potential will exist at times to meet 100% of customer demand.”

It notes that in regions such as South Australia, work is already underway to reduce the minimum number of synchronous generating units required for system security through the deployment of synchronous condensers, which has already succeeded in a dramatic reduction in system costs.

But that state still needs at least two of these syncons, big spinning machines that do not burn fuel, to maintain system strength. “Operation with fewer than two synchronous generating units online in South Australia is still under investigation,” it notes.

The release of the updated framework had been flagged a day earlier by AEMO boss Daniel Westerman, who had spoken of the pioneering nature of the work, which he said was not driven by ideology, politics or personal ambition, but by the data that shows this is where the world is heading.

“I think we ought to be prepared for that,” he told the Australian Energy Week conference.

Westerman says more than 300 potential gaps in knowledge have now condensed into the key strategic decisions that need consideration over the next two years, and AEMO is working with the “brightest minds in power system engineering and operations,” including from the UK, Ireland, Texas and California.

“It’s recognised internationally that Australia is among the first to grapple with the challenges this brings,” he said. “In terms of navigating this energy transition, AEMO is both ship’s crew and its cartographer.”

Australia’s record share of instantaneous renewables is 61.9 per cent, reached in November last year. Westerman says the share has gotten close to that a few times this year, with renewable shares of more than 60 per cent.

“I have no doubt that it will be broken again several times this year,” he says, and the ISP suggests multiple occasions it will reach 100 per cent by 2025. (South Australia regularly exceeds 100 per cent renewables, but it has links, and an outlet for surplus power, to Victoria, and will soon have a new one to NSW).

“Moving forward, it will be necessary to harness the capabilities of all power system assets in a technology-agnostic manner to maximise flexibility during periods where few or no synchronous generating units are operating,” the AEMO document says.

The document lists 46 priority things to do, but at least 12 are considered “headline” actions that have priority (see table above).

These range from revising system strength requirements, understanding what grid forming inverters can contribute, creating new market mechanisms, and managing periods of high rooftop solar output.

It also suggests trials for certain regions of the NEM to operate with only 100 per cent inverter-based resources, something that has not been achieved on the main grid to date.

Within the 12 “headline” actions, AEMO identifies four that appear to have priority over the others. This includes further work on understanding the operation of 100 per cent renewables, the rollout of ARENA’s funding program for grid forming inverters, and work on system strength needs and regulations.

As many have said, it’s not that the future is unclear, it’s how to get there. The biggest challenge in the transition is moving from one system to another, and keeping the lights on.