Household batteries are now being marshalled to deliver very fast response to grid security issues

French-based energy supplier Engie says its 2,800 strong home battery virtual power plant (VPP) based in South has been approved to deliver services for the newly created very fast Frequency Control Ancillary Services (FCAS) market, but it was an uphill battle getting it in.

The energy company believes that its home battery VPP is among the first to be approved for the new Very Fast FCAS market, which requires operators to respond in about a second to a fall or rise in grid frequency outside its normal operating range.

The Australian Energy Market Operator (AEMO) gave its nod to the South Australian VPP in June. 

Engie Retail general manager innovation Ryan Wavish hinted at the difficulty involved in registering a dynamic aggregation of thousands of small home batteries in the Very Fast FCAS market. 

He said the AEMO process is designed for large power stations, and not for the likes of a distributed energy VPP whose composition can change on almost a daily basis. He said it was a long, time-consuming process.

The issue is that AEMO’s registration process and portal is designed for large single assets, not fleets of small residential batteries. Every time a customer changed in the Engie fleet it had to effectively restart the registration process.

How the home battery VPP will operate in a market that, to date, has been dominated by big battery operators, is likely to be keenly watched by those who expect distributed energy resources (DER) to play a big role in energy services in future.

Although the aggregated capacity of the Engie fleet is small compared to the big batteries, each individual battery responds to the local frequency deviation and provides a raise or lower service as required.

“Engie’s VPP has already been called into action several times so far in 2024 to provide important grid support services, while only making a very minor impact on the normal battery operations – only needing to respond for a few seconds or minutes at a time,” Wavish says. 

There are seven companies with VPPs registered with AEMO and these can be approved to operate in different parts of the FCAS markets.

These include Discover Energy in South Australia; the Tasmanian government’s Hydro Electric Corp in NSW and Queensland; Energy Locals in NSW, Victoria and South Australia; Sonnen in NSW; and Engie, Shine Hub and AGL in South Australia.

In a report in 2022, Tesla said its Powerwall home batteries in its own SAVPP (South Australia VPP) are capable of providing a sub-250 millisecond response which technically meets the needs of the Very Fast FCAS market. 

The company tested the batteries installed in its Phase 3 rollout to ensure they could participate in the market and said its Phase 2 batteries were already providing Very Fast FCAS services.  Tesla has been approached to confirm whether these tests have materialised into full market participation.

The new Very Fast FCAS market started late last year, and initial experiments showed that smaller – 1 megawatt (MW) – batteries could generate  revenue on par with much bigger ones. 

“This highlights how residential batteries can play an important role,” says Wavish.

“The Very Fast FCAS market has typically been the source of the lion’s share of Contingency FCAS value since its inception, so this development is important to ensure our customers can keep enjoying great benefits from participating in the Engie VPP.”