The Australian Energy Market Operator (AEMO) has given renewables, distributed energy resources and storage the green light with the release of its 2020 Integrated System Plan, which it says sets out a plan to prepare the grid for coal’s inevitable exit and deliver $11 billion in benefits by 2040.

The key points of this enormous schedule for change in the Australian electricity system include expectations for: distributed energy resources (DER) to double or triple, providing 13-22% of total underlying annual energy consumption; more than 26GW of new variable renewable energy (solar and wind) to replace coal-fired generation, with 63% of coal-fired generation set to retire, and; a surge in “dispatchable resources” between 6-19GW to back up renewables, in the form of pumped hydro, fast-start gas-fired generation, battery storage, demand response and aggregated DER participating as virtual power plants.

To ease the transition from predictable, scheduled generation the AEMO plan also encourages work on power system services, including voltage control, system strength, frequency control, inertia, ramping and dispatchability.

Possibly most important to the realisation of its masterplan is a rebuild of the transmission grid, with strategically placed interconnectors and renewable energy zones (REZs), coupled with firming resources, to add capacity and balance variable resources across the NEM.

Plan ahead

AEMO managing director and CEO Audrey Zibelman said the plan represents an alignment of hoped-for integration of large amounts of variable clean energy generation with a supply network that will be fit for the task while meeting consumer expectations of affordable and reliable electricity.

“The ISP analysis confirms that as our coal plants retire, the least-cost transition of the NEM will be to a highly diverse portfolio consisting of distributed energy resources [DER] and variable renewable energy [VRE], supported by multiple dispatchable resources,” Zibelman said.

The plan identifies investments in transmission infrastructure and renewable energy zones which, when coupled with low-cost firming resources, will be the most cost-effective way to add generation capacity and balance variable resources across the NEM, she said.

“When implemented alongside market and regulatory reforms, the targeted transmission investments identified in the ISP will bring the right resources into the system in a timely fashion. This will create a modern, efficient and resilient energy system that delivers $11 billion in net market benefits weighted across the different ISP scenarios over the next two decades,” Zibelman said.

If AEMO sticks to what it calls an “optimal development path”, it anticipates that by 2035 there may be periods in which nearly 90% of demand is met by renewable generation.

Missing links

Over an 18-month period, AEMO consulted on and developed the ISP that includes the least-cost investments to optimise net market benefits and deliver low-cost, secure and reliable energy through a comprehensive range of plausible energy futures for the NEM.

The 2020 ISP identified four categories of transmission projects ‒ committed, actionable, actionable (with decision rules) and future ISP projects ‒ permitted to be developed by the transmission network service provider through the Renewable Investment Test – Transmission (RIT-T) process.

Actionable ISP 2020 projects include: an upgrade to the Victoria‒NSW Interconnector, with project completion expected in 2022-23; a new 330kV double-circuit interconnector between South Australia and NSW, with completion expected by 2024-25; a 500kV transmission upgrade to reinforce the NSW southern shared network and increase transfer capacity between the Snowy Mountains hydroelectric scheme and the region’s demand centres, with completion due by 2025-26, and; the Central-West Orana REZ Transmission Link, due in 2024-25.