Can residential solar be better integrated into electricity networks?

A report released by ENEA Consulting reveals that a suite of technologies is required to address power quality issues caused by increasing electricity generation from rooftop solar photovoltaic (PV) systems.

This report is a timely addition to drive solutions for Australia’s energy transition as consumers’ appetite for rooftop PV continues to grow.

The Future Grid for Distributed Energy report — led by Victorian distribution company CitiPower and Powercor in collaboration with ENEA Consulting — is part of a project supported by the Australian Renewable Energy Agency (ARENA).

Recent modelling by the Australian Energy Market Operator shows that distributed energy resources, such as rooftop PV and residential batteries, could provide 13–22% of annual electricity consumption in the National Electricity Market by 2040.

ENEA Consulting Partner and report author Olivier Lacroix said, “The preferred solution(s) for enabling further rooftop solar installations will depend on local network characteristics.

“Smart inverters cannot be considered a ‘silver bullet’. Electricity distribution companies will need to consider other solutions, including network upgrades, to complement smart inverters when managing high PV penetration,” he said.

“Smart inverters can act as a safety net to ensure that voltage does not reach excessive levels in regions where a high number of rooftop solar systems are installed to protect electricity infrastructure and customer appliances. However, this study found that at high PV penetration levels, smart inverters reduce voltage rise by significantly reducing the amount of consumers’ electricity that can be exported to the grid.

“At this point, other solutions need to be considered, including investment in network assets.

“We encourage distribution companies to build a wide range of low-voltage network power flow models,” Lacroix said.

“This will allow more confidence when inferring the networks’ ability to manage a certain amount electricity generation at the consumer level. It will also enable more informed investment decisions to support future rooftop solar uptake.”

Lacroix iterated that governments should also consider allowing dynamic export limits, which would mean that consumers’ electricity exports would only be reduced when required by the grid. This would also provide more flexibility to maintain the grid and potentially avoid expensive network upgrades that could place upward pressure on electricity prices.

The report also recommended further topics for study to complement the findings:

• Explore the potential of a fleet of behind-the-meter batteries to mitigate high voltage levels.
• Explore the potential of additional technologies and/or combining technologies to mitigate high voltage levels.
• Explore the management of high-voltage and low-voltage networks in a coordinated fashion to identify the best solution where voltage issues are expected on both sections of the grid.
   

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