Australia is at the forefront of global rooftop solar adoption, with an estimated 4.2 million solar systems installed by June 2025. This impressive figure translates to approximately 26.8 gigawatts of clean energy generation capacity that is directly feeding into local electricity networks for homes and businesses. While this increase in solar energy is a significant step toward reducing carbon emissions, it also presents new challenges for electricity grid operators as traditional fossil fuel sources are gradually being replaced by renewable energy.
Dr Julio Braslavsky, a Senior Principal Research Scientist at CSIRO, highlights a major issue arising from the high levels of solar installations: the pronounced fluctuations in power flow between utilities and residential homes, which can be likened to tidal changes. “During the evenings, households typically draw power from large generation facilities such as wind farms and gas plants, representing the “low-tide” period for local electricity grids,” he explained. “Conversely, during sunny days, around 40% of Australian homes generate their own electricity from rooftop solar panels. When the power generated surpasses household consumption, the surplus is exported back to the grid, marking the “high-tide” period.” In certain regions, such as South Australia, rooftop solar can meet 100% of the state”s electricity demand during these high-tide times.
Dr Braslavsky notes that the ability of local networks to manage these significant power swings is fundamentally limited by a technical issue known as “phase imbalance.” He describes this phenomenon as a typical characteristic of local electricity networks, arising from the uneven distribution of power across the three-phase systems that connect to homes. Most households are linked to a single phase and exhibit variable consumption and generation patterns throughout the day. The issue becomes more pronounced during significant swings in power due to the prevalence of rooftop solar, leading to increased inefficiencies, compromised power quality, and network congestion. This can be visualized as a three-lane highway where one lane is congested while the others remain largely empty. Severe cases of phase imbalance can also pose safety risks.
In response to the challenges posed by phase imbalance, a team from CSIRO collaborated with X, formerly known as Google X, in 2023 on a project named Tapestry. The aim is to explore smart inverter technology that can help stabilize grid operations in real time and mitigate the effects of these tidal power swings, thereby enhancing the network”s capacity to accommodate not only more rooftop solar but also home battery systems and electric vehicle charging stations.
Inverters play a crucial role in this process, converting direct current (DC) electricity produced by solar panels into alternating current (AC) electricity usable by homes and the grid. However, modern inverters have capabilities that extend beyond mere conversion; they can also manage the flow of electricity throughout the network. “Building on our foundational partnership with X, CSIRO has advanced the development and testing of innovative smart grid inverter designs capable of addressing phase imbalance in real-time and boosting network utilization,” Dr Braslavsky stated.
This innovation is not just confined to Australia. In October 2024, CSIRO showcased its smart inverter technology to energy leaders from Southeast Asia, including Indonesia”s state-owned utility, PLN. Indonesia faces comparable challenges, with significant inefficiencies and safety issues stemming from phase imbalance in its local distribution networks. PLN has shown keen interest in collaborating with CSIRO to develop and test a prototype inverter designed to increase capacity for rooftop solar and other consumer energy resources.
Supported by funding from Australia”s Department of Foreign Affairs and Trade, the CSIRO-PLN partnership aims to illustrate how smart inverters can alleviate congestion, enhance infrastructure efficiency, and contribute to electricity decarbonization. The project includes designing and testing a solid-state inverter that can dynamically balance electricity flows, utilizing real-world data from Indonesian and Australian networks for simulations. The team is also conducting workshops and lab visits to share insights and refine the technology, with plans to explore field trials to validate the inverter under actual network conditions.
To ensure the effectiveness of these smart inverters, the team is creating comprehensive computer models and conducting laboratory tests. These models will simulate the inverters” performance under real-world scenarios, including responses to uneven solar generation and abrupt demand changes. An encouraging finding from these simulations indicates that simplified inverter designs can effectively reduce phase imbalance by supplying corrective currents, paving the way for cost-effective solutions that could be broadly implemented across the grid. The initial low-power lab tests have been completed, and preparations for high-power trials at CSIRO”s Energy Centre in Newcastle are underway. The next steps involve real-time hardware-in-the-loop testing using Indonesian network scenarios, followed by a joint technical report and potential field demonstrations.
If successful, this initiative could enable both Australia and Indonesia to incorporate more rooftop solar energy without compromising grid reliability. Projections indicate that by 2050, Australia”s rooftop solar capacity could reach 72 gigawatts, with nearly 80% of detached homes in the National Electricity Market expected to have solar panels, effectively doubling current levels. The development of smart inverters will be critical in supporting this sustainable future.
