Looking back at FCAS on 1 August 2023

A spike in mainland raise FCAS prices for the 18:05 dispatch interval reminded us to not forget about FCAS when the energy market starts to steal the spotlight  (as it did yesterday).

With the Heywood interconnector constrained, and a lull in wind generation extending across many NEM regions, and the time coinciding with the evening demand peak, energy prices and FCAS prices were elevated for a good portion of the hour between 18:00 and 19:00.

A screenshot from the NEM prices widget (via ez2view) of the 18:05 interval shows, alongside energy prices, that FCAS raise prices were also high. Especially prices for the regulation and raise 6-second services.

Taking a very brief glance at the next-day bids and related information, we noted:

• Some (albeit smaller batteries) were rebidding with “Updated SOC close to limit” reminding us that energy supply from batteries has a limit, until the opportunity to recharge is taken.
• The 18:05 interval’s Raise Reg and 6 Sec FCAS prices were set through co-optimisation of offers in FCAS raise and energy markets. This points toward higher-priced energy offers being necessarily leveraged to find the overall lowest cost solution to meeting the required FCAS enablement levels and energy demand in the interval.

We may report further on this or additional features in the future, time permitting.