by David Edwards, Technical Visionary, Horizon Power
Horizon Power aims to deliver energy solutions for regional communities in Western Australia by developing a pathway to the effective management of high-penetration Distributed Energy Resources (DER) and energy storage. Through the DER trials in Carnarvon, Horizon Power is planning for a highly decentralised energy resource future where customers have a choice in how they manage their energy requirements, and solar PV and energy storage will play a critical part in transitioning to a cleaner, fairer and more efficient energy future.
Our industry is adapting to rapid change with rising levels of renewable energy generation distributed across our networks. Customer expectations are changing as technology impacts so many other parts of their lives, and their attitude, quite rightly, is that we, as an industry, will keep pace.
Across multiple sectors, we are seeing a wave of traditional businesses and services undergoing digitalisation by effectively leveraging frameworks like Industry 4.0, and using smart connected devices to transform data collection, build situational awareness and support data-driven decision making. We now have a myriad of new ways to connect to the hearts and minds of our customers through which we can co-create win-win outcomes.
By developing new customer-centric products that build value for the customers who remain connected to the network, we can shift from a supply chain model to an ecosystem in which the customer plays an important role and the distribution network, complemented by digital products and services, is considered a platform on which the customer can build.
Figure 1 shows a potential pathway from a supply chain to an ecosystemic approach to electricity service delivery. By taking our core product and using smart connected devices to digitally augment the way we connect to our customers ‘wants and needs’, we can leverage operational data and analytics to improve service delivery.
Traditionally reactive processes such as billing can be changed into an interactive journey, where the customer has the information they need to make informed choices about their energy consumption, or generation or storage, interacting with billing options in a near real-time experience.
Digital services can enhance power system optimisation through DER management that seeks the best possible outcome for the customer, building value into their investment while providing valuable support services to the network operator.
Eventually, we will reach a digital ecosystem where our relationship with our customers has subtly changed from consumer to trusted partner, and where a wide choice of DER and home automation products can be orchestrated to create a symphony of cooperation and co-value creation.
The ideal test environment
In preparation for this transition, Horizon Power is conducting a series of technology trials in the town of Carnarvon in the Gascoyne – Midwest region of Western Australia (WA) to consider economically-efficient options for microgrid operation. The trials are exploring the management of high penetration levels of DER, cloud-based aggregation of DER into a Virtual Power Plant (VPP), advanced data analytics and digital apps that provide customers with data on which they can make informed decisions.
Carnarvon, situated on the mouth of the Gascoyne River 900km north of Perth, has a population of approximately 5,500. In 2014, Horizon Power commissioned the 13MW gas-fired (with diesel peaking) Mungullah power station. Ownership of the power station offers control system access, and integration and optimisation options that would not be possible with an independent power producer operating under a power purchase agreement.
With an economic base of predominantly primary producers, Carnarvon experienced rapid uptake of solar PV in 2008-2011 with higher than average system sizes, typically 30kW, used to offset coolroom and water pumping power purchases.
The distribution system has a high feeder and transformer loading of solar PV, and requires sufficient spinning reserve to cover the variability in renewable energy generation caused by coastal weather patterns. Carnarvon was the first regional WA town to start pushing the boundaries of solar PV hosting capacity in 2011.
The town’s population has in the past held great enthusiasm for solar PV, with 121 customer-connected systems as well as two commercial solar farms operated by Solex (45kW) which was the first privately owned solar farm in Australia, and EMC (300kW).
The Carnarvon DER trials, which commenced in 2018, are primarily funded by Horizon Power with a $1.92 million contribution from ARENA’s Advancing Renewables Fund and include a team of researchers from the Engineering and Energy Discipline at Murdoch University.
This project aims to resolve the technical, operational and transitional barriers to a high-penetration DER business future by conducting a series of technology trials and experiments over three years, involving the monitoring and control of solar PV and energy storage.
The questions we seek to answer are:
- Do we understand the operational risks associated with a DER control solution?
- Can the control techniques we are developing manage DER in a microgrid to support Horizon Power’s high-penetration DER future assumptions?
- Can a DER management solution monitor and control energy storage to reduce peak demand and peak export?
- Can a control solution be used to increase DER hosting capacity and penetration of renewable energy into the network?
- Moreover, can the project provide market research concerning a customer’s willingness to embrace new technology and invest in PV and battery systems?
Our project hypothesis is that, in the future, if we can gain the level of visibility and control over distributed energy generation that we have had over centralised power stations for the last few decades, we can manage the contribution from DER to increase hosting capacity and achieve microgrid optimisation.
The problems associated with managing increasing levels of renewable energy in low voltage networks are widely acknowledged, but cost-effective mitigation of those risks is not widely understood. A great deal of work around the world aims to realise the benefits of managing DER in large grid systems such as the Southwest Interconnected System (WA) or the National Energy Market.
The Carnarvon DER trials aim to experientially understand how to manage DER in a microgrid environment, how DER orchestration can be used to remediate power quality issues and how we can effectively exchange DER value with our customers.
Exploring the impact of weather conditions
Key to the management of microgrids with high-penetration DER is gaining an understanding of the impact of weather patterns on renewable energy generation and customer load, particularly cloud events which can traverse a regional town such as Carnarvon in under 20 seconds, and how that renewable energy generation variability impacts the way the power system is operating.
The project has engaged 82 residents and businesses with solar PV systems as participants in the data acquisition phase of the trials.
Each participant was gifted a Solar Analytics solar smart monitor (Figure 2) to separately meter their solar PV system production and network load every five seconds. By separately metering, we have gained visibility of solar PV energy generated, behind-the-meter energy consumption and solar PV exported into the network at any given time during the day. In addition, we revealed the actual load which has been masked by solar PV for over a decade.
Data from each of the participants has been curated into a data lake, together with data from a weather station at our Carnarvon depot providing information on temperature, humidity, wind speed and direction, barometric pressure and solar insolation, as well as ten-second sky camera images recording cloud movement over the town.
Power station SCADA and Advanced Meter Infrastructure (AMI or smart meter) data from sentinel points around the network has also been imported to build one of the most concise weather-related data sets we have. Particular attention has been applied to the timestamping of the incoming data streams to ensure a co-incident data set that can support complex analysis and machine learning models.
We have assembled a data set that builds a comprehensive picture of how changing weather affects renewable energy generation and customer load, and how this in turn influences distribution network and power station operation (Figure 3).
The database is capturing 130 million data points per day, and we have employed compressed column store and fractal compression of data to accelerate Virtual Power Plant (VPP) dispatch engine queries, facilitating real-time decision making for DER control, as well as machine learning models to develop detailed forecasts of renewable energy generation across the entire network.
A collaborative effort
The second phase of the trials, completed in March 2019, was the installation of new combined solar PV and battery systems at the houses of an additional ten participants. Six of the existing data participants also received a battery and inverter to augment their legacy PV systems, and the Solex commercial solar farm received an inverter upgrade to part of its array.
These seventeen participants received a ‘Reposit Box’ DER controller, allowing Horizon Power to monitor and control their DER systems through aggregation into a VPP established in the Reposit cloud platform.
We have concentrated the majority of the new DER and system upgrades onto a single feeder with an already moderately high penetration of solar PV. The solar PV production on the Gibson Street’s low-voltage feeder regularly exceeds the combined average load on the feeder at midday, exporting its excess energy into the wider Carnarvon medium-voltage network.
By installing additional DER, we have created a high-penetration DER environment, a kind of laboratory environment, to test DER control techniques on a live network with real customers and variable weather.
Over the next 12 months, we are conducting a series of experiments using the customers’ DER systems to investigate the network impact of solar PV generation and behind-the-meter systems, confirming the viability of high-penetration DER in Horizon Power’s microgrid networks.
The team from Murdoch is using the collected data to develop statistical assessments of the impact of time of day and seasonal weather variation on solar PV generation at different levels of penetration into the microgrid, as well as DigSilent Power Factory simulations, evaluating the power system’s stability with cloud movements and complementary spinning reserve control strategies.
The use of Feed-in Management (FiM) strategies for solar PV and the effective use of short-term solar forecasting to assist those control strategies is seen as the primary objective to meet Horizon Power’s immediate need for FiM solutions.
Murdoch is developing assessment tools to investigate and overcome the impacts of future increases in DER on Horizon Power networks, using a k-means clustering model that identifies archetype or representative low-voltage feeders for effective and efficient modelling of the low-voltage networks.
The tools consider the location of DER in the power system and provide improved visibility of issues that arise when DER penetration increases. An evaluation of the impacts of the new features available in smart inverters and an assessment of forecasting tools using sky imaging are supporting the development of DER control methodologies, which Horizon Power can apply to its entire portfolio of microgrids.
The DER trials have given Horizon Power the chance to engage with leaders in DER control, VPP, forecasting and data analytics, building an ecosystem of partnerships in the pursuit of value co-creation and win-win outcomes (Figure 4). While there are contracts in place, the goal has been co-investment and interdependence.
Continuous interaction, an agile approach to technology development and weekly phone catch-ups fuelled a social process of innovation that complements an economic method of innovation. What would once have been considered a single value chain is changing into open competency-based networks of similarly minded innovators, to the benefit of our industry.
Horizon Power’s commitment to knowledge sharing as part of the ARENA funding agreement includes making the research database available through the ARENA knowledge sharing program at the end of the trials in 2021. Murdoch University will be publishing a series of research reports from the DER trials, and Horizon Power will publish project learnings from a utility perspective through the ARENA portal.
Conference presentations, engineering workshops, and industry and academic working group participation are ongoing as we seek to share the lessons learned with industry and academia promptly.
At the time of writing, the data analysis has produced valuable insights into the impact of cloud events on network voltage and inverter operation. Visualisations of the data insights can be seen on the project web page: horizonpower.com.au/our-community/projects/carnarvon-distributed-energy-resources-der-trial/.
About Horizon Power
Horizon Power is the Western Australian Government’s regional and remote power provider. We are passionate about what we do, and strive to ensure our customers receive safe and reliable power to their homes, businesses and communities.
Our people and their families live in many of the regional and remote communities they service and support. Spanning some 2.3 million square kilometres, this makes us responsible for the largest geographical catchment of any Australian power provider.
We operate 38 power systems delivering power to more than 110,000 homes, communities and businesses. This includes 32 microgrids tailored to meet the unique needs of some of the most isolated and remote communities in the world.
Horizon Power is making significant investments in developing its renewable energy capability and expertise. It currently has a number of initiatives underway exploring new and innovative ways of providing our customers with more sustainable, affordable power.