AEMO looks to EVs, data centres and industry to help ease overload of rooftop PV in middle of day

The Australian Energy Market Operator is looking to electric vehicles, data centres, industrial loads and other options to help ease the overload of rooftop solar PV in the the middle of the day.

AEMO has formally commenced an invitation to tender for what are known as Minimum System Load (MSL) Type 2 Transitional Services – essentially technologies that can create grid demand in the middle of the day when rooftop PV is often the dominant force in the grid.

Minimum system load has emerged as a major issue for the market operator in recent years, particularly in South Australia, where half of all households have rooftop PV and where the output from those systems can send demand levels to below zero.

AEMO has responded in various ways – initially by introducing measures to curtail rooftop solar, and then by seeking to contract big batteries to charge up in the middle of the day, or at least by sending instructions to do if demand levels falls to what it says are dangerously low levels.

The issue has become critical in at least three states – South Australia and Victoria in the country’s main grid, and in Western Australia, which hosts a large isolated grid and where two of the country’s biggest batteries have been built with the specific task of absorbing rooftop solar and flattening the so-called solar duck curve.

Now AEMO is looking for other technologies to help out, and its market briefing notes suggest that electric vehicle charging, data centres, industrial loads, co-generation, virtual power plants and other options may be able to help.

It is seeking such services in South Australia and Victoria, as well as two state grids which remain dominated by coal fired power generators, NSW and Queensland.

“More than one third of homes across the country now host rooftop solar systems, helping households and businesses reduce their energy bills and directly contributing to the decarbonisation of the energy system,” AEMO says.

“A concerted effort is required to ensure these consumer energy resources are effectively integrated into the power system as uptake increases, in a way that supports the secure and reliable delivery of electricity to all consumers now and into the future.

“With increasing daytime generation from DPV, operational demand on the transmission network is falling. During these periods, it may not be possible to dispatch enough large-scale plant above their minimum safe operating levels to deliver these essential security services.”

AEMO sought expressions of interest in the program late last year and these closed in January and it is now moving to the next phase of the process.

The type 1 services were limited to battery storage, and contracts were secured with two big batteries in Victoria, although none in South Australia, which is why big batteries such as Torrens Island and Blyth are sometimes instructed to stand by in case they are needed, although neither has yet been called on to charge.

AEMO says eligible technologies for the type 2 services must be new technologies, or new applications of existing technologies that have not been used before March, 2024. They also include long duration storage and contracts may last for up to 10 years.

“These services provide AEMO with pre- positioned, controllable resources that can increase load or reduce generation, helping to maintain secure operating conditions during low demand periods,” it says.

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