The Australian Government has launched two new Capacity Investment Scheme (CIS) tenders targeting the South-West Interconnected System (SWIS) in Western Australia, one of the country’s largest isolated power networks. The move is part of a broader national strategy to accelerate the energy transition and secure grid stability as renewable energy replaces fossil fuels.
The dual tender, announced on 29 August by Climate and Energy Minister Chris Bowen, is expected to stimulate up to AU$4 billion (US$2.62 billion) in private investment and deliver enough clean energy to power more than 900,000 households annually. It will also introduce 2.4GWh of storage capacity—sufficient to support evening peak loads for 550,000 homes over four hours.
Single-Stage Tenders to Accelerate Delivery and Increase Grid Resilience
According to the Department of Climate Change, Energy, the Environment and Water, these will be the first CIS tenders to adopt a streamlined single-stage process, designed to condense the typical nine-month bidding cycle to roughly six months. This consolidation of technical and financial proposals aims to expedite the signing of Capacity Investment Scheme Agreements (CISAs) and accelerate the deployment of critical infrastructure.
Both tenders are focused on delivering a combined 1.6GW of new renewable generation and 2.4GWh of dispatchable energy storage, which will directly feed into the Wholesale Electricity Market (WEM).
The WA tenders are part of a national CIS programme that targets the deployment of 40GW of renewable energy and dispatchable capacity by 2030. To date, six rounds of CIS have already locked in 12.3GW of generation and 6GW of storage, according to the government.
Tender registration is open until 10 October 2025, with submissions closing on 7 November. Successful bidders for Tenders 5 and 6 will be announced in March 2026.
Addressing Western Australia’s Unique Energy System Challenges
Western Australia’s SWIS operates independently of the National Electricity Market (NEM), making it especially reliant on local generation and storage. The system has faced increasing challenges from the high penetration of rooftop solar, which has significantly lowered daytime demand and caused a growing dependence on dispatchable storage during peak hours.
Tender 6 specifically aims to address these dynamics by procuring flexible, four-hour duration storage assets that can maintain grid balance when intermittent sources decline. The model follows the successful example of Tender 2, which earlier this year secured 2,595MWh of dispatchable capacity through four projects, including the Boddington Giga Battery and the Merredin Big Battery.
According to Energy-Storage.news, interest from the private sector remains strong, with prior rounds oversubscribed and several projects already under development. The CIS initiative is regarded as a cornerstone of Australia’s decarbonisation efforts, not only by unlocking investment but also by strengthening reliability across increasingly renewable-powered networks.
