At Indigo Power, we’ve been working closely with Mondo to manage our fleet of community batteries. The integration of Mondo’s Ubi controller has allowed us to operate these batteries as part of a Virtual Power Plant (VPP). This enables us to charge and discharge batteries based on various factors, such as weather forecasts, solar generation patterns, and electricity price predictions. While this system can respond instantly to grid operator signals, the broader commercial deployment of this functionality remains limited.
So, how does this all come to life in practice? Let’s walk through the daily operation of a community battery, starting with a typical day when everything is connected to the grid, before shifting to its role during a blackout or emergency.
A day in the life of the battery on a ‘normal day’.
A description of the community battery’s activity over a typical day gives a great example of how a community battery operates when connected to the grid.
6:00 AM
- Battery status: 25% charge
- Action: The battery is ready to soak up solar energy.
- Why it matters: All of the sites for the ARENA Community Batteries for Energy Resilience have on-site solar generation. Having the battery empty means it can be filled at no cost from the on-site solar PV system.
10:00 AM
- Battery status: Charging at 50kW from onsite solar.
- Action: Charges from onsite solar at 50 kW. Captures surplus that would otherwise be exported to the spot market at a negative value. If there is surplus solar, it is curtailed to avoid paying negative prices. If the prices are strongly negative, the battery can charge from the grid.
- Why it matters: Charging from on site solar is a low cost way to charge, but when prices are negative there may be opportunities to be paid to charge.
4:00 PM
- Battery status: 100% charge; wholesale price $35/MWh.
- Action: No discharge yet; waiting for stronger price signals. The battery discharges to on site load if solar generation is insufficient.
- Why it matters: The battery is ready to release energy when prices increase later in the day. As the price is positive, any surplus solar is exported to the grid.
5:00 PM
- Battery status: Rapid response to FCAS price spike.
- Action: Short burst of power to the grid.
- Why it matters: Provides a frequency control service that helps stabilise the grid generating additional revenue with minimal impact on storage capacity.
6:00 PM
- Battery status: Discharges at maximum capacity, wholesale price $180/MWh.
- Action: Battery discharges to meet peak demand and associated high prices.
- Why it matters: Physical hedge to support Indigo Power’s hedging, supporting stable electricity prices for customers.
10:00 PM
- Battery status: 15% charge
- Action: Switches to low-rate grid charging or stays empty depending on weather forecasts.
- Why it matters: Ensures the battery is prepared for the next day’s activity.
The same battery during an emergency outage.
When an outage occurs, the battery control system is ready to take action. Here’s how the battery responds to a storm-induced power outage:
3:00 PM
- Event: Severe winds drop a line, causing a grid voltage collapse.
- Action: The battery’s islanding relay trips in 100 milliseconds, isolating from the grid. It can back up critical circuits for extended periods or shed non-essential loads as charge depletes, ensuring only critical circuits remain powered at a lower battery charge.
- Why it matters: The battery continues to power critical loads without delay, maintaining reliability for essential services.
3:05 PM
- Battery status: 90% charge. Rooftop solar keeps charging between cloud bands.
- Action: Battery capacity at 90 %. Rooftop PV can keep topping up between cloud bands.
- Why it matters: Charging from solar in islanding mode is complicated for grid connected batteries. Very few battery manufacturers offer this functionality. The YACK02 battery currently being installed in Yackandandah is the first Pixii battery in Australia with the capability. Larger batteries are unlikely to have this functionality and rely on the significant amounts of battery storage to withstand long outages.
8:00 PM
- Battery status: 60% charge.
- Action: Non-essential loads are automatically shed to conserve energy.
- Why it matters: The battery continues to provide power to critical loads, extending run-time up to 14 hours. The run time is longer if only critical circuits are backed up at the design stage.
5:00 AM (Next Day)
- Grid restored: Battery at 40%.
- Action: Smooth reconnection begins, and the battery resumes its normal charging schedule.
- Why it matters: The system restores normal operations without the need for manual intervention, ensuring a seamless transition back to grid power.
The community batteries replace generator technology, with no diesel fumes, no manual switch‑overs, no human intervention or panic. For host sites that need to be extra certain of their back up energy supply, provisions are included in the energy supply agreement for the host site to reserve battery capacity if they expect a grid outage or emergency event.
The value of community batteries.
On a regular day, the community battery operates based on site load, weather forecasts, and price signals. During a power outage, it automatically switches to islanding mode, focusing solely on maintaining power for critical loads. This energy resilience ensures the value of community batteries extends beyond financial and environmental benefits.
Ben is Indigo Power’s Managing Director. He has a passion for collaborative initiatives that positively impact our communities. Ben leads our skilled and committed projects team, driving the uptake of community-scale clean energy technologies in communities around Australia.