Author:
Ally Winning, European Editor, PSD
Date
08/29/2023
PDF
Tesla’s Virtual Machine Mode (VMM) has been installed at Australia’s second largest Li-ion battery to provide stability to the grid by emulating mechanical inertia.
One of the biggest problems for electricity grids when adding more renewable energy sources is replicating inertia. Inertia is naturally found in the heavy equipment used in fossil fuel plants. The generators and motors in the plant rotate at the same frequency as the grid, usually at either 50 or 60 Hz depending on the country. That rotary effect acts as a buffer against a rapid change in supply or demand. For example, if a lot of demand is placed on the grid, its frequency drops. However, the equipment at the plant acts in the same way as a shock absorber and slows the rate of change. The same goes if a large amount of energy is sent to the grid in a short space of time, which tends to happen with the intermittent nature of renewables. A power grid without inertia would be unstable and offer lower power quality. In the worst case scenario, a lack of inertia could even cause blackouts. As we change over to renewable energy, fossil fuel plants, and their heavy rotating equipment are being shut down and this phase out could endanger efforts to build a reliable renewable energy powered grid.
In an effort to overcome the inertia problem, Tesla has developed a service that has the ability to simulate inertia in grids using batteries. The company has been testing its approach in partnership with Neoen at the latter’s 150 MW / 193.5 MWh battery storage facility Hornsdale Power Reserve (HPR) in South Australia. The result of those two years of extensive trials is that Neoen has recently secured approval from the Australian Energy Market Operator (AEMO) for its grid-forming inverters to deliver inertia services to Australia’s National Electricity Market. This means that batteries can now provide inertia services at scale, in the same way that gas and coal power plants have done in the past.
To accomplish the task, Tesla’s Virtual Machine Mode (VMM) has been installed at HPR - Australia’s second largest lithium-ion battery. Virtual Machine Mode has been designed to provide stability to the grid by virtually emulating mechanical inertia. Along with built-in inverters, Virtual Machine Mode can create grid-forming dynamics that strengthen the grid by responding to added and rejected loads and maintaining quality voltage. In South Australia, HPR can provide up to 3,000 MWs of inertia using Virtual Machine Mode, around half of the state’s inertia requirements. Located in a critical part of the network, HPR can automatically provide stability to the South Australian grid, which has reached 64% renewable penetration over the last 12 months, with a target of 100% renewable by 2025. Neoen’s batteries can also provide energy arbitrage, fast frequency response and frequency regulation at the same time.
This initiative was supported by the South Australian Government, who committed AUD$15m across 5 years through their Grid Scale Storage Fund, and from the Australian Renewable Energy Agency (ARENA) who contributed AUD$8m as part of their Advancing Renewables Program.
