Merriwa microgrid

The first step in this trial was to develop a low voltage connected microgrid at Merriwa, capable of supplying power to identified premises along Bettington Street, in the centre of town during major outages.

The microgrid includes small scale power generation (solar panels and a back-up diesel generator), storage (batteries) and control technologies. The microgrid will be able to operate during planned and unplanned power interruptions – switching on to maintain supply automatically to homes and businesses in the trial area.

The microgrid is intended to improve Merriwa’s resilience to disruptive events by maintaining access to local services and businesses within the microgrid area including the RSL and Country Women's Association rooms.

Ausgrid has considered a range of possible locations, with a focus on areas where we need to improve system reliability and resilience for customers. Merriwa has been selected as the preferred location because: 

- The existing network configuration means there is a risk of extended outages to the area.
- The conditions at our Merriwa Depot are right for this project, with the right amount of space, sunlight and support for an effective trial our climate assessments show that the Merriwa and Upper Hunter areas will be some of the most impacted by climate change across Ausgrid's system in coming decades. 
- The technology is now at a stage that we are confident it will work reliably and cost effectively. 
- The microgrid generation and storage infrastructure has been installed at Ausgrid’s Merriwa Depot.

System Component Overview:

- Main Switchboard – allows connection of Solar, BESS, Generator & Mains grid
- Solar PV Array – 100 existing JINKO EAGLE panels, 152 new SUMEC Phono panels all fed into a new common inverter.
- Solar Inverter – 110 kW Sungrow 3 phase solar inverter
- Generator Set – 550kVA Genelite diesel generator
- Battery Energy Storage System (BESS) - 2 x 535kWh 2-hour Sungrow power stacks

Ausgrid climate impact research for the Upper Hunter shows by 2050 we can expect to see an increase in all types of climate risks such as heat, storms and bushfire.

Microgrids can help support communities during planned and unplanned outages. They improve electricity reliability by providing a back-up power supply. In Merriwa, the microgrid will focus on keeping key services running, such as the pharmacy, grocery, fuel providers as well as the RSL and Country Women’s Association. During an outage, the identified businesses along Bettington Street Merriwa will continue to operate during what would normally have been an outage.

During an unplanned event, such as a power outage or natural disaster, the microgrid operates to ensure a continuous supply of electricity to critical loads. Here's a brief summary of how it works:

1. Detection and Isolation: The microgrid detects the unplanned event and isolates itself from the main grid to prevent any disturbances from affecting the local system.
2. Transition to Island Mode: The microgrid transitions to island mode, where it operates independently from the main grid. This involves switching to local energy sources like solar panels, batteries, or backup generators. This requires some manual intervention from the Ausgrid control room to ensure it is safe for the microgrid to operate. 
3. Load Prioritisation: Critical loads, such as essential infrastructure within the scope of the microgrid, are prioritised to receive power.
4. Energy Management: The microgrid's energy management system optimizes the use of available resources, balancing supply and demand to maintain stability and efficiency.
5. Communication and Control: Advanced communication and control systems monitor the microgrid's performance, making real-time adjustments to ensure reliable operation.
6. Reconnection: Once the main grid is stable, the microgrid can reconnect and synchronise with it, resuming normal operations.

At the completion of testing & commissioning there will be 27 connections to the microgrid including: Merriwa Pharmacy, Merriwa Tyre Service, Merriwa Cakes & Pastries, Merriwa Newsagent, IGA Supermarket, Merriwa CWA, Merriwa Home Hardware, Merriwa RSL Club and the BP Service Station.

There are many variables at play to provide estimated restoration times for a hypothetical future outage. It is best to refer to Ausgrid’s website for expected outage restoration times.

The construction of the Microgrid was funded by Ausgrid’s Network Innovation allowance from the Australian Energy Regulator. A customer’s electricity bill is made up of 3 components Transmission, Distribution & Retail. As a Distribution Network Service Provider (DNSP) the revenue Ausgrid can recover from customers is inherently fixed for every 5-year regulatory period.

The construction and management of a new microgrid can indeed impact electricity bills, but the extent of the increase depends on several factors:

1. Initial Capital Costs: Building a microgrid involves significant upfront costs, including the installation of solar panels, battery storage systems, generators, and control systems.
2. Operational and Maintenance Costs: Once operational, the microgrid will incur ongoing costs for maintenance, fuel for generators, and management. These costs are generally lower than the initial capital costs but still contribute to the overall expense.
3. Energy Savings and Efficiency: Microgrids can lead to long-term savings by reducing reliance on the main grid, especially during peak demand times when electricity prices are higher. They can also improve energy efficiency and reduce transmission losses.

In summary, while there may be an initial increase in electricity bills to cover the costs of building and managing the microgrid, the long-term benefits, including improved reliability, energy savings, and potential incentives, can help mitigate these costs. The construction of the microgrid can also defer the need to construct more costly and impactful infrastructure such as long transmission lines and provide similar benefits.