Highlights:
- The challenge of the ‘excess’ share of renewables in South Australia offers interesting tips for other markets from a GW-sized electricity market.
Last week, South Australia saw the apparently bizarre situation of the national grid operator killing itself, or asking owners to turn off their rooftop solar systems in the state, even if they were asked to. which increases the demand by switching on more appliances and other power. hungry equipment. This apparent dichotomy is easily explained, and also points to the challenges many grids will face as the share of renewable power increases.
The challenge
For AEMO (Australian Energy Market Operator), the challenge in South Australia is due to the high proportion of rooftop solar in the state. When a typhoon knocks out the grid connectivity with the rest of the national grid, it faces a unique challenge of ‘minimum operational demand’ as it calls it, which falls to an unacceptably low level. level, leaving it with some tools to manage the stability of the grid if a second storm. or a similar event is a strike. In an explanation it shared, it says ” If rooftop solar generation is high, the demand for grid-scale supply will naturally be extremely low, shifting to grid generators. Currently, these generators provide a variety of essential system services, including frequency control, system power, voltage management, redundancy, etc. At times of very low operational demand, these services must be obtained from elsewhere or, if that is not possible, AEMO must intervene to maintain the grid in a safe operational state”.
That’s why AEMO is pushing for better inverter standards where it can ‘control’ the inverters remotely, allowing it to turn off the inverters when needed in these situations. In addition to this of course, the grid has been upgraded with more transmission lines between states that will allow excess power to be exported to other states in states that produce excess renewable power, such as in this case. Of course, if the same situation happened in peak summer, then AEMO would be easier should manage the situation, as the peak load, and the demand would be higher, allowing the solar rooftop generation to be absorbed locally in the energy guzzlers like ACs etc.
AEMO’s difficulty highlights how high the renewable share of grids will shift concerns from managing peak demand, to managing periods of minimum demand, when renewables can have not the same effect. In countries like India, we have states like Karnataka that live at risk, with a high share of renewables above 50%, but the stability of the grid is ensured thanks to the connection to the national grid.
Solutions to this issue in the future will include many large storage facilities that can absorb higher generation, besides renewable energy consumption setups such as Hydrogen electrolysers, which can on and off very quickly.
