Chris Morris is a semi-retired power station engineer in New Zealand who has commented here on No Minister occasionally and on other NZ blogs. In mid 2023 he emailed me about a series of four articles he had written for the blog of Judith Curry in Australia.

I published a summary of the key points of his first article here, Part 1, Australia’s Transition to Renewable Energy

Part 2 looks specifically at South Australia(SA) since it has advanced the most in becoming a fully renewable power grid, and he especially focuses on what he calls “AroundTheCornerism” – claims that the latest obvious problems with the 100% renewable target will be solved by some technology breakthrough.

A couple of quick starting points about SA

  • It’s power grid is not an independent, self-contained grid but part of a larger one, specifically Victoria where the large synchronous coal and gas-fired stations work to support the South Australia experiment. 
    ** Synchronous here means the power generators increases and decreases in output are synchronised with the demand rising and falling. Asynchronous means power generators that do not always match demand because they’re intermittent, not continuous (i.e. night time/cloudy days and windless days affecting solar and wind power)
  • This is not unusual: The German grid is supported by conventional generation from neighboring systems including coal resources in Poland.
  • Synchronous condensers are basically the same as synchronous generators, the difference being they lack the ability to generate power, instead consuming power to keep the assembly turning, synchronised with the grid (think of a flywheel) to provide inertia, voltage control and other grid factors. You could convert a steam plant to being a synchronous condenser simply by removing the steam generation and adding motors.
  • The SA experiment is not to create an asynchronous independent grid operating on wind and solar. What they’re trying to do is test how to integrate a large amount of wind and solar:
    • As part of a larger grid.
    • Supported by the synchronous generators (coal and gas-fired power stations supplying baseload power) of its neighbours in that larger grid.
    • Installing special synchronous condensers to replace the synchronous generators that they are retiring.

There are two challenges in reaching the target:

  1. Replacing fossil fuels with renewables.
  2. Upgrading the entire grid to work with renewables.

They have to be done concurrently for the plan to work, but at present they’re not because the first is easier than the second. The article discusses specific engineering/costing challenges and notes that SA is “grappling” with these rather than solving them:

  • Converting retiring coal-fired plants to operate as synchronous condensers has failed due to problems with ownership structures and cost sharing, plus the focus on simply shutting plants as fast as possible.
  • Building brand new synchronous condensers is the current plan.
  • New high voltage transmission lines will have to be built, with 2022 plans to build 5 for $A12.7 Billion.
  • Residential solar may have to be cut to enable grid-level solar because of a need for storage and frequency control (eg, large inverter / battery farms like that at Hornsdale).
  • Nobody is proposing using such inverters for grid-scale storage; Hornsdale is used for frequency control: “The inverter-based work is much less developed and much further away”.
  • There are a lot of short-term incentives in the cost mix that are not tied to long-term demands.
  • Every increase in grid wide renewable penetration will compound the costs and challenges, not reduce them because the solutions of replacing synchronous generation, adding storage, adding synchronous machines and vastly increased management of the grid are costly, makeshift, and stopgap.

The bottom-line (and it really is such) is that all of these costs to support renewable energy in various ways, so that the whole grid remains reliable, cannot be hidden forever. AEMO is currently seeing inertial shortfalls and poor system security.

================

Australia’s Transition to Renewable Energy:
Part 1