Western Australia’s rooftop PV expansion set to displace large-scale solar

October 12, 2020
Facebook
Twitter
LinkedIn
Reddit
Email
Image: ARENA.

Rooftop PV is set to be the fastest-growing form of new capacity in Western Australia (WA), with renewable energy forecast to reach a minimum of 70% generation capacity by 2040, a new roadmap for the state reveals.

Called the Whole of System Plan, the blueprint provides a 20-year outlook on the future of WA’s main electricity network, the South West Interconnected System (SWIS), through four scenarios.

This article requires Premium SubscriptionBasic (FREE) Subscription

Try Premium for just $1

  • Full premium access for the first month at only $1
  • Converts to an annual rate after 30 days unless cancelled
  • Cancel anytime during the trial period

Premium Benefits

  • Expert industry analysis and interviews
  • Digital access to PV Tech Power journal
  • Exclusive event discounts

Or get the full Premium subscription right away

Or continue reading this article for free

The modelling forecasts renewable generation to triple by 2040 as rooftop PV continues to displace coal as well as large-scale solar, while battery storage is increasingly deployed to help stabilise the system. Coal-fired generation declines under all paths, and partially exits the market in the mid-2020s in the low demand growth scenarios.

“It's the most comprehensive modelling study ever undertaken into the future of WA's electricity system and it will support our transition to low-cost electricity,” said WA energy minister Bill Johnston. “Our state is embracing renewable generation, with one in three households having rooftop solar panels, this signifies that battery storage will play an important role in our future.”

While 1,291MW of rooftop PV is assumed to be in the SWIS in 2020, this is expected to increase to between 2,258 MW and 5,037 MW by 2030. The report says there are two reasons why rooftop PV will feature prominently: there is no market cost attributed to installing new capacity and surplus energy produced by systems spills out into the network throughout the day, meaning it is effectively dispatched ahead of all other capacity and displaces large-scale generation.

Under all scenarios, a common theme is that the volume and density of rooftop PV in the grid provides an opportunity for large numbers of individual systems to be aggregated and coordinated to provide energy and essential system services.

The expansion of rooftop PV will result in displacement for both coal and solar. Indeed, two of the paths foresee no additional large-scale solar, while the other two predict new developments only where there is lower rooftop PV relative to overall demand.

Under all four scenarios, wind generation is the preferred form of large-scale capacity, ranging from an additional 60GW to 3,002MW by 2030, while new storage capacity is expected to be between 187MW and 2,235MW.

The expansion of distributed energy resources (DER) such as rooftop PV and battery storage was also included in the Australia Energy Market Operator’s (AEMO) recent Integrated System Plan, which says output from DERs could treble to 22% of Australia’s total consumption by 2040.

AEMO provided input for Western Australia’s Whole of System Plan. Its CEO, Audrey Zibelman, said: “WA’s energy system continues to rapidly transform as investment increases in rooftop solar and household devices that store energy, including batteries. Care must be taken now to manage this transition towards a more decarbonised, decentralised and digitalised power system.”

Read Next

November 20, 2025
Australia achieved a record-breaking 5.3GW of solar PV installations in 2024, marking a recovery for the market while highlighting the nation's unique position as a rooftop-dominated solar economy.
November 20, 2025
SunCable has submitted its 20GW Muckaty Solar Precinct proposal to Australia's EPBC Act for federal environmental assessment.
November 19, 2025
The world invested US$554 billion into solar PV projects in 2024, leading renewable electricity generation sources, according to IRENA.
November 19, 2025
Recurrent Energy has sold its 275MWdc Gunning hybrid solar-plus-storage project in New South Wales, Australia.
November 18, 2025
The 94MW Gunsynd Solar Farm has been registered in AEMO's Market Management System as the Queensland project prepares for commissioning.
November 17, 2025
Renewable energy developer SunCable has signed an Indigenous Land Use Agreement (ILUA) with the Powell Creek Native Title Holders, marking a milestone for the company’s AAPowerLink project in Australia's Northern Territory.

Upcoming Events

Solar Media Events
November 25, 2025
Warsaw, Poland
Solar Media Events
December 2, 2025
Málaga, Spain
Solar Media Events
February 3, 2026
London, UK
Solar Media Events
March 24, 2026
Lisbon, Portugal
Solar Media Events
June 16, 2026
Napa, USA