Australia’s frequency control markets should be modified to monetize the rapid deployment capabilities of energy storage systems, power systems operator Australian Energy Market Operator found in a report on the Hornsdale Power Reserve project, which they published on April 5.
The report titled Initial operation of the Hornsdale Power Reserve Battery Energy Storage System found the 100MW/129MWh lithium ion system was capable of providing a range of rapid and precise frequency control ancillary services to stabilize the state’s grid.
South Australia’s ancillary services market specification does not address performance requirements for regulation frequency services, and essentially considers them equal and interchangeable, with providers paid the same price per MW of enabled service, regardless of performance.
The report said: “Current frequency control ancillary service market arrangements could be modified to specifically recognise the rapid and accurate response capabilities of batteries, and therefore enhance their ability to earn income from providing them.
“Batteries, and some other inverter-based technologies, have demonstrated that they are capable of rapid delivery of a large and sustained response to a change in frequency. In some circumstances this can be particularly valuable, such as following a large disturbance, or when the power system is operating with low inertia.
“The current methods for assessing and commoditizing frequency response involve performance assessment against a slow moving change in frequency, and do not therefore recognise, or reward, the more rapid response capabilities of batteries, and some other inverter-based technologies.”
The project, arguably the biggest energy storage system in the world, provides a range of grid-scale services under commercial agreements between the South Australian Government, battery provider Tesla, and the French owner and operator Neoen.
It was the first time batteries had been used for regulation frequency control in Australia’s national energy market. These services had previously been delivered by gas and coal generated power.
The system also provides energy arbitrage, reserve energy capacity, and network loading control ancillary services (South Australia requires 10MWh is reserved for this), as well as being registered to provide eight different frequency control service.
Neoen has around 30MW of the discharge capacity for use in the energy market, the rest is reserved for power system reliability, which to date has not been needed.
The system was first called into action a month after it was commissioned in November last year. The battery has been deployed twice to cover outages at the coal-fired Loy Yang facility in the state of Victoria.
The Hornsdale ESS was deployed after two tornadoes destroyed elements of the power infrastructure, which caused the system to trip, in 2016 leaving 1.7 million South Australia residents without power. Subsequent storms and heat waves have caused additional outages.