Balancing Australia's Ocean Of Electricity

Australia is leading the world in rooftop solar adoption. By June 2025, 4.2 million rooftop solar systems had been installed nationwide representing 26.8 gigawatts of clean power generation capacity connected directly to local electricity networks that serve homes and businesses.

This surge in solar power is helping reduce carbon emissions, but it's also creating new challenges for electricity grid operators where the traditional burning of fossil fuels for electricity generation is being replaced by cleaner and sustainable sources of energy.

Dr Julio Braslavsky, Senior Principal Research Scientist at CSIRO, says one of the biggest challenges in local networks with high levels of solar-powered homes is the emergence of large 'tidal' swings in power flows between power utilities and homes.

"In the evenings homes typically consume power, which flows from large power generation plants, such as wind farms, hydroelectric, coal and gas-fired power plants. Let's call this the 'low-tide' time in local electricity grid operation," he said.

"In the middle of a sunny day, however, today about 40% of Australian homes generate their own power from rooftop solar panels. When the rooftop solar generation exceeds the power consumption in the houses, the excess power is 'exported', flowing back to the grid, supplying other homes and beyond. Let's call this the 'high-tide' time in local electricity grid operation."

Since Australia leads the world in rooftop solar installations, such reversal in power flows between low and high 'tides' in Australian electricity grids can be dramatic, pushing the operation of local electricity networks to their capacity limits – in South Australia the entire state electricity demand is often 100% supplied solely by rooftop solar during 'high-tide' times.

Dr Braslavsky says the capacity of local networks to safely sustain such tidal swings in power is fundamentally constrained by a phenomenon technically known as 'phase imbalance'.

"Phase imbalance is a normal characteristic of local network operation and represents the unevenness in powers flowing through the three-phase utility poles and wires systems at any given point in time," he said.

Phase imbalance arises during normal operation because most homes are connected to a single phase (one of three) and have different consumption/generation patterns through the day. The imbalance, however, is aggravated during the large tidal swings in power produced by lots of rooftop solar and can lead to increased inefficiencies, power quality problems and network congestion – think of it like a three-lane highway where one lane is jammed while the others are nearly empty. Severe phase imbalance can lead to potential safety issues.

Harnessing solar power with smarter inverters

To tackle the challenge of phase imbalance, researchers from CSIRO—Australia's national science agency—teamed up in 2023 with X, the innovation lab formerly known as Google X, through a project called Tapestry . Their goal? To investigate smart inverter technology to help balance grid operation in real time, mitigating the impacts of 'tidal' power swings, and expanding the capacity of the network to safely connect not only more rooftop solar, but also home batteries and charging of electric vehicles.

Inverters are versatile electronic devices that convert the direct current (DC) electricity generated by solar panels into alternating current (AC) electricity used in homes and on the grid. But modern inverters can do much more than just convert power—they can also help manage how electricity flows through the network.

"Stemming from the foundational collaboration with X , CSIRO moved to developing and testing innovative designs of smart grid inverters that can tackle phase imbalance in real time and increase network utilisation in local electricity distribution networks," Dr Braslavsky said.

A global collaboration: Australia and Indonesia

This innovation isn't just relevant to Australia. In October 2024, CSIRO presented its smart inverter technology to Southeast Asian energy leaders, including Indonesia's state-owned utility PLN . Indonesia faces similar challenges, with high inefficiencies, safety concerns and congestion issues caused by phase imbalance in its local distribution networks.

PLN expressed strong interest in collaborating with CSIRO to develop and test a prototype inverter that could help unlock more capacity for rooftop solar and other consumer energy resources.

"Through its development initiatives in Southeast Asia, Australia's Department of Foreign Affairs and Trade is funding a CSIRO-PLN partnership that aims to demonstrate how smart inverters can reduce congestion, improve infrastructure efficiency and support electricity decarbonisation," Dr Braslavsky said.

The joint project involves designing and testing a solid-state inverter that can dynamically rebalance electricity flows, then simulating performance using real-world data from Indonesian and Australian networks. The project team is also conducting workshops and lab visits to share knowledge and refine the technology, and are exploring field trials to validate the inverter in live network conditions

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Testing and modelling

To make sure these smart inverters work as intended, the team is developing detailed computer models and running lab tests. These models simulate how the inverters behave in real-world conditions, including how they respond to uneven solar generation or sudden changes in demand.

One exciting result from the simulations shows the potential of simplified inverter architectures to reduce phase imbalance by supplying corrective currents. This opens the door to cost-effective solutions that could be deployed widely across the grid.

What's next?

The team has already completed low-power lab tests and is preparing for high-power trials at CSIRO's Energy Centre in Newcastle. The next phase includes real-time hardware-in-the-loop testing using Indonesian network scenarios, followed by a joint technical report and potential field demonstrations.

If successful, this innovation could help Australia and Indonesia integrate more rooftop solar without compromising reliability. By 2050, rooftop solar capacity in Australia is expected to reach 72 gigawatts, with nearly 80% of detached homes in the National Electricity Market (NEM) having solar panels (doubling current levels). Smart inverters like the ones being developed in this project will be essential to making that future work.

This article was first published online in Energy Magazine .