03 Jun 2026 19:25 → 04 Jun 2026 19:25 AEST
| Capex total (greenfield) |
$422.96M
Shown in table How this was derived Reference |
|---|---|
| Capex refurbishment |
—
|
| Capex / MWh storage |
$391,625
Shown in table How this was derived Reference |
| Fixed OPEX (annual) |
$5.72M
Shown in table How this was derived Reference |
| Fixed OPEX / MW-yr |
$21,200
Shown in table How this was derived Reference |
| Variable OPEX / MWh |
$0.00
Shown in table How this was derived Reference |
| Fuel cost / GJ |
—
How this was derived Reference |
| Heat rate GJ/MWh |
—
How this was derived Reference |
Confidence: medium · Status: ai estimated · Capex basis: estimated · AI checked 04 Jun 2026
Notes
Barn Hill BESS is a publicly announced, not-yet-committed AGL battery project in South Australia. AGL states the broader Barn Hill Wind Farm and Battery Project includes up to 270 MW of battery capacity with up to 4 hours duration, and AEMO lists Barn Hill BESS as 270 MW / 1,080 MWh in the October 2025 South Australian Electricity Report. No Barn Hill-specific capex, EPC contract, financing close, DUID, FID, O&M contract, battery supplier, or commissioning date was found. Capex is therefore estimated from Aurecon/AEMO 2024 Energy Technology Cost and Technical Parameter Review for a 200 MW 4-hour large-scale lithium-ion BESS co-located with a large renewable installation: $471/kW power component + $274/kWh energy component + scaled land/development cost. A dedicated-grid-connection benchmark from the same source would imply about AUD 451.2 million, so the selected AUD 436.6 million should be treated as an indicative 2025 planning estimate, not reported project cost. Fixed opex uses Aurecon's 4-hour BESS fixed O&M of AUD 12,800/MW-year plus indicative 20-year extended warranty of AUD 8,400/MW-year, scaled to 270 MW. Variable O&M is left null because Aurecon states BESS long-term service agreements are not typically fixed/variable. For asset life, AGL states about 35 years for the overall wind farm and battery project, but the BESS-specific Aurecon assumption is 20 years economic/technical life, potentially extendable to about 25 years or further with battery upgrades; the BESS-specific 20-year value is used in the financial profile. Emissions intensity is recorded as zero direct operational emissions, consistent with regulatory treatment of BESS as storing electricity rather than generating emissions; lifecycle and grid-charging emissions are not included.
Barn Hill BESS is not yet registered with a DUID in the sources found. AEMO lists it as a publicly announced South Australian storage development of 270 MW / 1,080 MWh, not committed or anticipated. AGL's July 2025 project factsheet says the wind farm, battery and associated infrastructure received development consent on 31 January 2025, but the battery has a different development timeline and its investment decision is expected later than the wind farm FID. No Barn Hill BESS-specific capex, O&M, heat-rate/efficiency, or battery augmentation contract was found. Capex is therefore estimated by scaling Aurecon/AEMO's 2024 4-hour co-located Li-ion BESS EPC benchmark for a 200 MW / 800 MWh project to 270 MW / 1,080 MWh. This estimated capex excludes the wider Barn Hill wind farm and transmission scope and may exclude or only partly include land/development costs. Fixed opex uses Aurecon's 4-hour BESS fixed O&M plus 20-year extended warranty allowance (12,800 + 8,400 = 21,200 AUD/MW-year). Variable O&M is set to 0 AUD/MWh because Aurecon reports no separate variable O&M for BESS long-term service agreements. Efficiency is 85% round-trip efficiency at beginning of life for a 4-hour BESS. Direct operating emissions are assumed zero for the battery itself; charging-energy emissions depend on source and dispatch and are not reflected. Asset life uses Aurecon's 20-year BESS design/technical life; AGL states about 35 years for the broader Barn Hill Wind Farm and Battery Project, creating a project-vs-battery-life distinction. Major refurbishment/closure note: Aurecon says BESS life may be extended to about 25 years after condition assessment and thereafter by battery upgrades; AGL says project end-of-life decommissioning/rehabilitation would occur under a Decommissioning and Rehabilitation Plan.
Barn Hill BESS is publicly announced/development-stage, not yet committed, and no Barn Hill-specific EPC, capex, O&M, warranty, tolling or closure cost disclosure was found. AGL states the Barn Hill project includes up to 360 MW wind, a new 275 kV transmission connection, and, at a later stage, a 270 MW battery with up to 4 hours storage. AEMO's 2025 South Australian Electricity Report lists Barn Hill BESS as a publicly announced storage development with 270 MW and 1,080 MWh. The capex estimate scales Aurecon's 2024/2025 AEMO benchmark standalone 200 MW / 800 MWh 4-hour lithium-ion BESS total EPC plus land/development cost of AUD 334.1 million to 270 MW / 1,080 MWh: 334.1m * 270/200 = AUD 451.035m. This excludes project-specific transmission, taxes/import duties, interest during construction and contingency per Aurecon assumptions, and may not capture Barn Hill-specific sharing of infrastructure with the wind farm. Fixed O&M is based on Aurecon's 4-hour BESS fixed O&M plus 20-year extended warranty: AUD 12,800/MW-net-year + AUD 8,400/MW-net-year = AUD 21,200/MW-net-year; scaled to 270 MW gives AUD 5.724m/year. Variable O&M is treated as zero/unallocated because Aurecon reports BESS long-term service agreements are not typically structured as fixed/variable. Efficiency is beginning-of-life round-trip efficiency at point of connection for 4-hour BESS. Asset-life assumption uses the BESS 20-year warranty/design-life basis from Aurecon/CSIRO; AGL separately states an overall Barn Hill Wind Farm and Battery Project asset life of about 35 years, which may refer to the integrated project/wind asset rather than battery cell life. Development/closure note: AGL states development approval was granted on 31 January 2025 and that the battery investment decision is expected after the wind farm and associated infrastructure FID; no closure date was identified.