Before Australia officially committed to a target of net-zero carbon emissions by 2050, and a world away from the COP26 conference in Scotland, the real work of reducing Australia’s greenhouse gas emissions was already well underway.
Four years ago, State Government-owned energy utility Horizon Power commenced a series of Distributed Energy Resource (DER) trials in the coastal Gascoyne- Midwest town of Carnarvon, approximately 890km north of Perth, Western Australia.
Working with Reposit Power as its technology supplier and a team of researchers from Murdoch University, the regional and remote power provider is leading the way into a renewable energy future for remote microgrids with the learnings from its Carnarvon DER trials.
Horizon Power faces both unique challenges and opportunities due to its 38 regional and remote microgrids in some of the most remote communities of Australia, and the inherent high cost of supplying electricity to these customers.
“Like all utilities, we’re grappling with the challenge of accommodating more and more customer rooftop photovoltaic solar,” Horizon Power’s Future Technology and Innovation Manager, David Edwards, said.
“This is both a technical and a business problem. As rooftop solar uptake changes the way our network operates, how do we adjust our business model to suit that?”
Trial helping to analyse renewables impact on the network
The Carnarvon trial was designed to resolve the technical, operational, and transitional barriers to a high penetration, distributed energy future, and build Horizon Power’s expertise in distributed energy management.
It demonstrated the extent to which Horizon Power could disconnect parts of the network for considerable periods of time, allowing some customers to be supplied solely from renewable energy.
“We needed to understand how to manage the variability of renewable energy and its impact on the network, to ultimately increase renewable energy penetration across all of our remote networks,” Mr Edwards said.
“Firstly, we gathered data to understand what was happening on the Carnarvon network, particularly in relation to customer solar systems, to quantify it in real-time. Secondly, we needed to analyse that data.”
The trial recruited 116 Horizon Power customers in Carnarvon who already owned rooftop solar PV systems, with smart monitoring devices installed at each property to monitor the participants’ energy consumption.
Primarily, the task was to determine, at any given time of day, the amount of energy each customer rooftop solar system generated and consumed, as well as the amount of grid energy being drawn from the Carnarvon network by each participant.
“We were gathering this data every five seconds, so we built a very detailed picture of exactly what was going on with those solar systems. We could see how cloud cover and the changes in sunlight were causing them to operate differently,” Mr Edwards said.
“If the solar PV system was meeting a load at the home and suddenly the sun went behind a cloud, that manifested as a rapid transference of load over to the grid. We needed to understand how that was changing the network dynamics.
“The risk of inverters tripping under these circumstances can be disruptive to the network, requiring more capacity at the centralised power station and reducing the customer solar that can be accommodated on the microgrid.”
Potential to take entire towns to 100 per cent renewable energy
During the trial, Horizon Power created an embedded microgrid within its main Carnarvon network. Switchgear, a BESS/grid-forming inverter and a microgrid controller, enabled the utility to switch the Gibson Street feeder away from the rest of the Carnarvon network during the middle of the day; when there was sufficient solar energy to power everyone on that feeder.
The result was that the solar power from 24 customers supplied 36 homes on the same feeder.
The significance of the Carnarvon trial is that the data analysis, and the technical conclusions, can be applied to all the systems in Horizon Power’s portfolio of microgrids, and provide valuable insights for other network operators around the country.
“We wanted to understand what happens when you take a legacy network infrastructure to inverter-only-based generation. We needed to look carefully at things like frequency and voltage management, and how we use the battery control processes to maintain stability and power quality,” Mr Edwards said.
Crucially, the Carnarvon trial demonstrated that it is possible to take an entire town to 100 per cent renewable energy. It is also demonstrating the important role of customer rooftop solar as customers move away from being just a prosumer of energy to an active participant in the supply of energy to their community.
More broadly, the Western Australian Government energy utilities have released a joint commitment to address climate change in support of the government’s commitment to reach net zero greenhouse gas emissions by 2050.
Each utility is playing a pivotal role towards a low carbon economy for the Western Australian community by trialling and implementing renewable energy solutions.
“Here in Western Australia, we have an important role to play in decarbonisation, not only in terms of our own environments, but also in trialling new, clean energy technologies for a wider industry benefit,” Horizon Power CEO, Stephanie Unwin, said.
“We are using advanced distributed energy technology to orchestrate customer rooftop solar with a centralised solution that combines solar energy, battery storage and back-up gas generation. Our regional presence and proud history of delivering energy solutions for regional communities is enabling us to lead the way towards net zero carbon emissions by 2050 or sooner.
“We have the solutions to achieve zero net carbon energy generation and distribution and we are at the cutting edge of deploying this technology across regional Western Australia.”
The trials were recently shortlisted for the 2021 Industry Innovation award, conducted by peak industry association for power networks, Energy Networks Association.