AEMO’s emergency powers prevent blackouts during high peak demand

candle due to blackout

Last Friday demand was forecast to break the all-time record of 10,119MW seen in March 2022. AEMO’s pre dispatch forecasting was showing demand peaking at 10,656MW but by 5:30 it had fallen short with Queensland’s demand peaking at 9,750MW.

With a record peak demand forecast due to high temperatures and humidity, AEMO utilised its emergency powers to prevent blackouts across Queensland. As the evening peak approached on Friday, AEMO intervened in the market and at 4:25pm  they enabled Reliability and Emergency Reserve Trader (RERT).

Between 5.30pm and 9.30pm members of the RERT panel reduced consumption on site or increased on site generation to reduce the overall QLD demand. These panel members are compensated by AEMO under individual arrangements if their services are used.

Prior to the dispatching of RERT, AEMO had sent lack of reserve notices to the market to encourage generators to offer more supply. Also, the QLD energy minister said the system would be tight, but he was confident of avoiding blackouts.

As previously discussed, Queensland relies on wind and solar generation to provide clean cheap electricity, but it is currently reliant on coal fired generation to provide the reliable backup when the sun has gone down, and the wind is not blowing.

Currently on a “normal” day demand is easily filled with a combination of solar, wind, gas and coal but on extreme day like last Friday the system becomes more dependent on scheduled generation like gas and coal fired powered stations.

Following the failure at Callide C3 and Callide C4 the state is down 840MW of availability and on extreme days this generation can mean the difference between “normal” prices and the lights staying on and very high prices and the possibility of load shedding.

If it was not for AEMO stepping in, demand may have increased, and spot prices may have certainly capped out close to $15,500/MWh. While very high prices are not good for end users, they are a signal for investment.

If high spot prices occur, it may encourage increased participation in the market and new generation being built but currently the uptake of renewable projects and storage has been slow.

Queensland has high ambitions to replace the coal fleet with renewable and storage but days like last Friday only reinforce that coal fired generation still plays a significant part in the security and price outcomes in the QLD market.

Edge2020 have an eye on the energy market, enabling us to support price  benefits as well as customer supply and demand agreements. Our clients rely on our experts to ensure they are informed, equipped, and ideally positioned to make the right decisions at the right time. If you could benefit from an expert eye on your energy portfolio, we’d love to meet you. Contact us on: 1800 334 336 or email: info@edge2020.com.au

The South Australian island and running on renewables

On November 12th a series of storms passed through South Australia that had the potential to black out the whole state, as had previously happened in 2016. Whilst parts of South Australia did lose power, it was far less dramatic than the last weather event due to a significant amount of work that has been undertaken by AEMO to build a more secure grid since the 2016 blackouts.

In 2017 AEMO released a review of the events that had blacked out the state; the main cause was of course the extreme weather that had knocked over transmission lines as well as some wind farms not meeting protection standards. Similar to 2016, it was destructive storms that passed through South Australia and damaged the network on the 12th November. At 4:59 PM, the market was notified of a significant power system event due to the tripping of multiple transmission lines. Both elements on the Tailem Bend – Southeast 275kV transmission line had tripped. Some transmission towers were damaged and had fallen over, resulting in the South Australian grid being disconnected from the NEM. On Saturday at 6:03 PM, AEMO notified the market that South Australia had been reconnected to the NEM after the 275kV transmission line at Tailem Bend was returned to service.

During events like this AEMO invokes its power to manage system security; however, this time, it went a step further and constrained off-rooftop PV to maintain a secure level of Distributed PV (DPV) generation. AEMO switched off as many rooftop PV installations as possible during the middle of the day, a rare occurrence known as “islanding” of the state grid to maintain stability, designed to keep the DPV below the secure threshold. PV generation is not as easily controlled as other sources. At times South Australia can meet all domestic demand for power via rooftop solar and sends surplus to Victoria but this cannot be managed in an islanded state, therefore requiring the curtailment of the rooftop PV allowing AEMO to manage scheduled and semi-scheduled generation assets to maintain system security.

Smart metering is required to enable the shutting down of rooftop PV systems, however not all South Australian PV systems can be controlled remotely as they have older inverters. This resulted in only 50% of systems being curtailed. Over time as more rooftop PV systems are installed using smart inverters, there will be more control of their output. Currently, AEMO can control 100MW of PV generation, but during the recent event, it also used voltage control to trip off a further 300MW of rooftop PV out of approximately 1,000MW of installed capacity.

The South Australian network has now been re-synchronised to the NEM, and electricity is flowing between South Australia and the other states of the NEM as before. While South Australia was isolated from the NEM for a week, South Australia was powered by wind and solar for up to two-thirds of its electricity demand, with gas providing the difference. System stability is a delicate balance between the supply of electricity, the types of generators providing the electricity and the electricity demand from end users. This time, part of the solution was to encourage end users to consume more electricity, enabling a higher generation level. Before the curtailment, South Australia was supplied by over two-thirds of its demand via renewable generation.

While high levels of renewable generation are good for keeping electricity costs down, the savings can be eroded by high-frequency control costs and the need for a more expensive gas-fired generation to fill the gap when the sun is not shining, and the wind is not blowing.

Edge2020 have an eye on the energy market, enabling us to support customer supply and demand agreements. Our clients rely on our experts to ensure they are informed, equipped, and ideally positioned to make the right decisions at the right time. If you could benefit from an expert eye on your energy portfolio, we’d love to meet you. Contact us on: 1800 334 336 or email: info@edge2020.com.au