By Zainab Rizvi, Te Pūnaha Matatini
Microgrids and other localised technologies hold significant potential for enhancing the resilience of energy systems. Digital modelling is showing decision-makers in post–Cyclone Gabrielle Tairāwhiti the effect of microgrids, before they decide whether to invest in them.
Any good builder will tell you to measure twice and cut once. This same deliberate thought and evaluation can be applied to infrastructure, thanks to the emergence of highly available data, digital modelling, digital twins and artificial intelligence.
Measuring twice can be achieved by exploring infrastructure changes, expansion and maintenance within a digital representation of that infrastructure. By observing the effects on the infrastructure – and the service it provides – along with the level of investment required, you can carefully consider the ramifications of your decisions before investing in infrastructure expansion, renewal, maintenance or change.
Energy infrastructure, and the energy systems that it supports, needs careful thought in a rapidly changing world. More frequent severe weather and other climate change–related developments – including increased electricity demand due to the move to electrification (such as electric vehicles), and new technology like microgrids and green hydrogen – all affect decisions about infrastructure expenditure.
An energy system provides energy services to end users through a distribution network by energy conversion. Energy conversion includes generation from hydropower plants, thermal power plants, and solar and wind farms. The distribution of energy requires complex infrastructure. The whole system interacts with multiple agents, including power generators, distributors, utilities companies and end users, and regulatory bodies.
Microgrids and other localised technologies hold significant potential for enhancing the resilience of energy systems. A microgrid is a self-sufficient energy system that serves a specific geographic area, such as a community, campus, or industrial site. It can operate independently or in conjunction with the main grid, providing a reliable power source during outages.
One of the primary benefits of microgrids is their ability to disconnect from the main grid and operate autonomously during disruptions like natural disasters. This capability ensures that critical facilities, such as hospitals and emergency services, continue to receive power even when the main grid fails. Additionally, microgrids often incorporate renewable energy sources like solar and wind, coupled with battery storage, which not only enhance resilience, but also reduce carbon emissions.
Localised technologies, including distributed energy resources like rooftop solar panels and small wind turbines, further contribute to grid resilience by diversifying the energy supply and reducing dependency on centralised power plants. These technologies can be rapidly deployed and scaled to meet local needs, making them ideal for remote or disaster-prone areas.
Tairāwhiti Gisborne was clearly identified as a disaster‑prone area after the devastation wrought by Cyclone Gabrielle in 2023. The team that I am working with is using a digital model of Aotearoa New Zealand’s electricity transmission network to explore the potential of microgrids in the Tairāwhiti Gisborne region.
We travelled to Tairāwhiti Gisborne after Cyclone Gabrielle to engage with the community about how microgrids could provide resilience against severe weather events. After an initial wānanga at Te Pa o Penu (Rongo-i-te‑Kai) and insightful kōrero with Tarsh Koia, Manu Caddie, Harley Dibble and others, we decided to measure how the deployment of microgrid technology in Tairāwhiti Gisborne would affect national transmission of electricity. This measurement provides a baseline of the associated cost or value – in terms of energy distribution – of using localised technologies to meet some or all of the energy demand in Tairāwhiti Gisborne. In this research, we are considering the energy needs of residential users, which include heating, cooling, hot water, cooking, transportation, food and medicine preservation, and water security.
The objectives of energy systems at the residential level are different to the objectives of the regional or the national grid level system. At the national level, the goal is to manage the energy system to ensure uninterrupted power supply, maintain the quality of the generated electricity, and dispense all the electricity produced.
For the energy system at the residential level, the goal is to reduce electricity bills, ensure energy storage in case of power outages and prevent damage to the household. This is a complex system, so we need an evaluation model that can encompass the differing objectives at different scales of the system.
New Zealand has mathematical models for replicating and simulating different electricity generation, pricing, and distribution scenarios. Models like Virtual Serial Port Driver and JADE are available in the public domain and can be modified to test for microgrid adoption at a regional level. At present, we are testing different microgrid adoption scenarios in Tairāwhiti Gisborne.
Our initial results indicate that if Tairāwhiti Gisborne can reduce its demand through microgrids, the surplus power generated by the hydropower stations at Tuai can be used to supply electricity to other regions. It was interesting to note that decrease in demand in one location (Tairāwhiti Gisborne) affected generation not only in the central North Island region, but also in the South Island. Additionally, electricity trading prices were reduced at peak hours throughout the region.
These initial results show that using localised technologies like microgrids to meet demand in Tairāwhiti Gisborne is potentially a win-win since it not only provides energy resilience and lower-cost energy to the region, but also provides value to the national energy system by reducing the need for generation elsewhere (e.g., Huntly), and lowering transmission workload into the region. This is relevant as, recently, Transpower has allowed for more water to be used from lakes to alleviate power shortages. Our results show that by adopting microgrids, we can reduce demand on the national grid, which would prevent stress on our hydro storage.
Self-reliance for energy needs is also important as Tairāwhiti Gisborne has the fifth-highest electricity rates in the country, while its residents’ average income is less than the national median. By adopting microgrids, Tairāwhiti Gisborne can become a revenue source as opposed to a cost centre in the energy system.
The integration of microgrids and localised energy technologies offers a robust solution for improving energy resilience, ensuring stable and sustainable power supply in the face of increasing environmental and infrastructural challenges – especially in disaster-prone areas like Tairāwhiti Gisborne.
Our initial modelling has shown the local and national benefits of adopting this approach in Tairāwhiti Gisborne, and we will continue to measure twice so that the community can confidently cut once in infrastructure decisions. //
Te Pūnaha Matatini is the New Zealand Centre of Research Excellence for complex systems.