Australian Energy Market Operator wants more powers to switch off excess solar

Any home with rooftop solar could be switched off this summer to prevent blackouts, if emergency powers are granted to the electricity market operator.

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The Australian Energy Market Operator believes there is an “urgent need to establish emergency capability” to turn off household rooftop solar systems to prevent summer blackouts.

In a stark warning, AEMO says South Australia cannot wait for new rules from the State Government regarding the installation of new solar systems and wants authority to switch off existing systems.

From September, new rooftop solar must be capable of being switched off remotely when too much power is generated into the electricity grid.

In a report published on Thursday, AEMO said the requirement for new systems was just one of three management strategies.

It also wants powers to switch off individual existing customers – rather than whole suburbs – and for SA Power Networks to be able to fiddle with voltage levels to get rooftop solar systems to trip off.

The problem is when too much power comes from rooftop solar, there is not enough demand to keep the big generators running, leading to instability and therefore blackouts.

The problem is when too much power comes from rooftop solar, there is not enough demand to keep the big generators running, leading to instability and therefore blackouts.

AEMO wants to be able to switch off 300 to 400 megawatts of power if necessary. The coal-fired Northern power station at Port Augusta was rated at just over 500MW.

AEMO said SA Power Networks had been experimenting with the voltage and could trip off solar in a way that was “effective, safe and has minimal customer impact”.

Blacking out individual customers would only be done as a last resort but could be done “relatively quickly (to existing rooftop solar) … with minimal upfront cost”.

This was “preferable” to blacking out groups of customers, it said.

AEMO managing director Audrey Zibelman said the grid was in a better position going into this summer than last – but major challenges remained.

“As we continue to see the increasing shift towards non-traditional generators and the increasing take up of household rooftop photovoltaic, we are encountering new challenges of managing voltage, system strength, and inertia,” Ms Zibelman said.

Audrey Zibelman, managing director of AEMO: “We are encountering new challenges of managing voltage, system strength, and inertia.”

SA was particularly vulnerable if disconnected from the rest of the national electricity market – as happened in February and usually at least once a year.

It said a fire in July which damaged transmission company ElectraNet’s equipment linking SA to Victoria would constrain that interconnector for 12 months.

The planned interconnector to NSW – which is expects to be built by 2024 – was essential to improving SA's grid and would reduce the problem of “islanding” SA.

Energy and Mining Minister Dan van Holst Pellekaan said the report showed “just how critical Project EnergyConnect (the NSW project) is for energy security in SA”.

“It is vital to ensure SA maximises output from renwable sources including home solar systems,” he said.

“It will drive increased investment in renewable energy generation delivering cheaper, cleaner and more reliable energy to SA and NSW.”

AEMO’s call for existing solar systems to be switched off when needed was supported, a government spokesman said.

The AEMO report - the Electricity Statement of Opportunities - said SA’s position was improving and it did not expect to need to have to disconnect existing solar systems after this summer.

Overall grid reliability would get better across the next few years - but trouble loomed for states dependent on coal-fired power.

“It is great to see how industry’s investment in new resources improves the reliability outlook for this summer,” Ms Zibelman said, noting an additional 4300MW of new variable renewable energy capacity will be operational this summer compared to last summer.

“In future years, the declining reliability of the ageing coal fleet and scheduled plant closures contribute to projected increases in unserved energy (when there is insufficient supply), particularly in NSW and to some degree in Victoria.”

The situation in NSW would be serious from as soon as 2023-24.

Originally published as Australian Energy Market Operator wants more powers to switch off excess solar