Australia is gearing up for another significant push in grid-scale energy storage, with AusEnergy Services (ASL) set to open the sixth round of its Capacity Investment Scheme (CIS). This tender will seek 2.4GWh of dispatchable capacity in Western Australia, aimed squarely at bolstering flexibility and reliability in the state’s main electricity network.
The move forms part of the federal government’s long-term plan to deliver an additional 32GW of renewables and battery energy storage systems (BESS) by 2030. Tender 6 specifically targets projects connecting to the South-West Interconnected System (SWIS) – the grid that supplies Perth and surrounding regions – and, by extension, the Wholesale Electricity Market (WEM).
A Grid with Unique Challenges
Unlike the interconnected networks on Australia’s east coast, Western Australia’s power system is physically isolated. It’s split into two separate grids:
- SWIS – serving the state’s southwest, including the capital.
- North West Interconnected System (NWIS) – covering the mining-intensive Pilbara region.
The SWIS has seen one of the world’s highest penetrations of rooftop solar, creating a “duck curve” challenge: extremely low daytime demand followed by steep evening peaks. This has increased the urgency for flexible capacity solutions, such as commercial and industrial energy storage systems, to smooth supply and reduce reliance on gas peaker plants.
Tender 6: Key Requirements and Structure
ASL’s latest market brief confirms that projects must be based in Western Australia and capable of delivering dispatchable energy into the WEM. Hybrid renewable-plus-storage projects are allowed, but only as “non-assessed hybrid projects” – meaning the renewable generation component will not be considered in the capacity contract evaluation.
One of the most notable changes is the streamlined, single-stage application process introduced in Tender 5. This merit-based approach condenses the procurement timeline from nine months to roughly six, with bidders required to submit full technical and financial proposals upfront.
Tender assessments will give strong weighting to community engagement and First Nations participation – signalling the growing importance of social licence in Australia’s clean energy build-out.
A Proven Appetite for Battery Investment
The CIS programme has already seen strong industry interest. Earlier this year, Tender 2 for the WEM awarded contracts to four major battery energy storage projects – the Boddington Giga Battery, Merredin Big Battery, Muchea Battery, and Waroona Renewable Energy Project. Collectively, these will deliver 654MW / 2,595MWh of four-hour storage by 2027, surpassing the original procurement target.
With the first six tenders expected to deliver over 12.3GW of generation and 6GW of dispatchable storage capacity, the CIS is well on track to meet its 2030 targets.
Why This Matters for the C&I Energy Storage Market
While the tender is aimed at utility-scale developers, the ripple effects extend to the commercial and industrial (C&I) energy storage sector. Large-scale BESS deployments help stabilise wholesale prices and improve grid reliability, creating better conditions for businesses investing in behind-the-meter storage solutions.
For Western Australia, where grid constraints and high peak tariffs remain a challenge, the growing presence of battery energy storage systems in the SWIS could accelerate the adoption of C&I ESS, especially in manufacturing, agriculture, and resource industries.
The Bigger Picture
Tender 6 is not just about adding capacity; it’s about preparing the grid for a future dominated by variable renewables. By front-loading social engagement, tightening timelines, and encouraging investment in four-hour storage systems, Western Australia is positioning itself as a proving ground for flexible grid solutions.
For developers, investors, and the wider energy storage supply chain, the message is clear: the Australian market is open, competitive, and moving fast. Those ready to deliver reliable, socially responsible storage projects will find fertile ground in the SWIS – and beyond.
