Owner: Hydro Tasmania
Status:
Technology Type: Storage - Pumped hydro
Fuel Type: Hydro - Water
DUID:
Capacity: 0 MW
Full Commercial Use Date:
Expected Closure Year:
Closure Date:
29 May 2026 04:00 → 30 May 2026 04:00 AEST · data through 30 May 2026, 04:00
| Capex total (greenfield) | $2,725.71M |
|---|---|
| Capex refurbishment | — |
| Capex / MW | $3,634,286 |
| Capex / MWh storage | $227,143 |
| Fixed OPEX (annual) | $15.80M |
| Fixed OPEX / MW-yr | $21,071 |
| Variable OPEX / MWh | $0.00 |
| Fuel cost / GJ | — |
| Heat rate GJ/MWh | — |
All monetary values shown in 2026 real AUD (CPI-escalated). Confidence: medium · Status: ai estimated · Capex basis: estimated · AI checked 04 Jun 2026
Notes: The generator appears to correspond to Hydro Tasmania's Cethana PHES project under Battery of the Nation. Current owner material gives an estimated project cost of AUD 2.6 billion in CY2023 real dollars, not a final construction outturn; the project had not reached FID in Hydro Tasmania's December 2025 update and 2024-25 annual report. Capex per MW is calculated as AUD 2.6b / 750 MW. Capex per MWh is calculated using the EPBC referral's approximately 14,500 MWh storage figure; the user's 12,000 MWh input conflicts with official project sources stating approximately 20 hours storage, approximately 14,500 MWh or 750 MW for 20 hours. Fixed O&M and VOM are technology-default estimates from AEMO/Aurecon PHES assumptions because no Cethana-specific O&M contract or budget was found. Fixed O&M uses the closest 24-hour PHES scenario at AUD 73,500/MW-year; applied to 750 MW gives AUD 55.125m/year. Variable O&M is included in fixed O&M per Aurecon. Efficiency is the midpoint of Aurecon's 75-80% PHES round-trip efficiency range. Asset life is the midpoint of Aurecon's 80-100 year technical/design life range; major electro-mechanical refurbishment is expected at roughly 25-30 year intervals. Direct operational emissions intensity is set to 0 tCO2/MWh for a non-combustion pumped hydro storage asset, but Hydro Tasmania notes reservoir emissions quantification is an emerging issue and not fully covered by its program.
[AI 2026-06-04] The generator record supplied by the user is 'Battery of the Nation - Stage 2b' with 750 MW and 12,000 MWh. Web research indicates Hydro Tasmania's current specific project matching this is the Cethana pumped hydro project: 750 MW and 20 hours storage, i.e. 15,000 MWh. The capex_per_mwh_aud field is calculated using the owner-reported 20-hour/15,000 MWh configuration. If the supplied 12,000 MWh registry assumption is used instead, capex is approximately AUD 216,667/MWh. Current owner estimate is AUD 2.6 billion in CY2023 real dollars; older 2019 estimates of about AUD 1.50m/MW are superseded by more detailed planning and construction-cost escalation. Fixed O&M and variable O&M are not project-specific disclosed values; they are technology default assumptions using AEMO/Aurecon PHES 24-hour storage estimates, selected as closest to the current Cethana 20-hour duration. Major refurbishment assumption is from AEMO/Aurecon: electro-mechanical major refurbishment at about 25-30 year intervals and civil design life around 100 years. No closure date found; the project is not yet at FID and, as of Hydro Tasmania's January 2026 update, remains in approvals/EIS development.
[AI 2026-06-04] The specific AEMO/NEM project record for 'Battery of the Nation - Stage 2b' lists 750 MW and 12,000 MWh, with 4 x 187.5 MW units, status publicly announced/proposed. Hydro Tasmania's current flagship pumped hydro project at Cethana is closely aligned but is described by Hydro Tasmania as 750 MW with 20 hours of storage (15,000 MWh), not 12,000 MWh. The capex value used is Hydro Tasmania's current reported Cethana estimate of $2.6 billion in CY2023 real dollars; capex_per_mwh is calculated against the user-supplied 12,000 MWh, so it differs from a calculation using Cethana's current 15,000 MWh storage capacity. O&M, efficiency and asset life are not generator-specific reported values; they are estimates/defaults based on AEMO/GHD 2025 pumped hydro assumptions, interpolated to a 16-hour / 12,000 MWh storage duration where applicable. Project remains pre-FID / approvals-stage: Hydro Tasmania says the project only proceeds if there is a strong commercial case and benefits Tasmania, with further geotechnical studies, business case analysis, approvals and Tasmanian Parliament approval still required. Major refurbishment is implicit in AEMO/GHD's 100-year technical life assumption, with regular maintenance/refurbishment assumed to maintain efficiency; no closure year was identified.
[AI 2026-06-04] AEMO/NEM generator information identifies Battery of the Nation - Stage 2b as a 750 MW / 12,000 MWh proposed pumped-hydro project, but Hydro Tasmania's current public Cethana project materials describe the preferred Battery of the Nation pumped-hydro project as 750 MW with about 20 hours of storage, implying about 15,000 MWh. The capex and fixed opex values above are not reported project costs for Stage 2b; they are 2025 AUD estimates based on AEMO/GHD pumped-hydro cost parameters, linearly interpolated to the user's provided 16-hour duration between GHD's 10-hour and 24-hour PHES cases. Hydro Tasmania's 2019 prefeasibility Cethana option was smaller at 600 MW / 6,700 MWh and reported $900 million including contingency, about $1.5 million/MW, but this is old prefeasibility data and does not match the current 750 MW configuration. Current project status: still in approvals/business-case development; one EPBC referral was withdrawn in April 2025, but Hydro Tasmania's December 2025 update states it is working on an updated referral and that a final investment decision has not yet been made. No closure date was found; 100-year life is a technology assumption from AEMO/GHD for PHES.
Model: gpt-5.5 · Reasoning: medium · Fetched 04 Jun 2026 08:47 · ID: resp_019ecf89d3010d2a006a20ae8b407c8193b3d2c1c262123b55
{
"generator_identity": {
"site_name": "Battery of the Nation - Stage 2b",
"duid": null,
"owner": "Hydro Tasmania",
"region": "TAS1",
"technology_type": "Storage - Pumped hydro",
"fuel_type": "Hydro - Water"
},
"financial_profile": {
"generator_type_normalised": "pumped_hydro",
"capex_total_aud": 2725714286,
"capex_year": 2025,
"capex_basis": "estimated",
"capex_per_mw_aud": 3634286,
"capex_per_mwh_aud": 227143,
"fixed_opex_annual_aud": 15803571,
"fixed_opex_per_mw_year_aud": 21071,
"variable_opex_per_mwh_aud": 0,
"fuel_cost_per_gj_aud": null,
"fuel_contract_notes": "No fuel contract identified. Pumped hydro uses water as the storage medium; pumping energy is bought from the electricity market when demand/prices are low or renewable supply is abundant. This is an energy-arbitrage input rather than a fuel cost per GJ.",
"heat_rate_gj_per_mwh": null,
"efficiency_pct": 76.4,
"emissions_intensity_tco2_mwh": 0,
"asset_life_years": 100,
"discount_rate_pct": null,
"source_confidence": "medium",
"data_status": "partially_verified",
"notes": "AEMO/NEM generator information identifies Battery of the Nation - Stage 2b as a 750 MW / 12,000 MWh proposed pumped-hydro project, but Hydro Tasmania's current public Cethana project materials describe the preferred Battery of the Nation pumped-hydro project as 750 MW with about 20 hours of storage, implying about 15,000 MWh. The capex and fixed opex values above are not reported project costs for Stage 2b; they are 2025 AUD estimates based on AEMO/GHD pumped-hydro cost parameters, linearly interpolated to the user's provided 16-hour duration between GHD's 10-hour and 24-hour PHES cases. Hydro Tasmania's 2019 prefeasibility Cethana option was smaller at 600 MW / 6,700 MWh and reported $900 million including contingency, about $1.5 million/MW, but this is old prefeasibility data and does not match the current 750 MW configuration. Current project status: still in approvals/business-case development; one EPBC referral was withdrawn in April 2025, but Hydro Tasmania's December 2025 update states it is working on an updated referral and that a final investment decision has not yet been made. No closure date was found; 100-year life is a technology assumption from AEMO/GHD for PHES."
},
"sources": [
{
"field_name": "site_identity_capacity_status",
"value_text": "Battery of the Nation - Stage 2b; owner Hydro Tasmania; storage - pumped hydro; Hydro - Water; 4 units; 187.50 MW each; 750 MW; 12,000 MWh; publicly announced; proposed.",
"value_numeric": 750,
"unit": "MW",
"source_url": "https://www.accc.gov.au/system/files/public-registers/documents/Luke%20Edwards%20Annexure%20%28LE-4%29%20-%2005.06.23%20-%20PR%20-%20MA1000024%20Brookfield%20Origin.pdf",
"source_title": "Statement in support of application for merger authorisation - Annexure LE-4, AEMO Generation Information extract",
"publisher": "ACCC / AEMO generation information extract",
"published_date": "2023-06-05",
"confidence": "medium",
"raw_excerpt": "Existing Generation and New Developments TAS1 | Project | Battery of the Nation - Stage 2b | Hydro Tasmania | Storage - Pumped hydro | Hydro - Water | | 4 | | 187.50 | | 750 | 750 | 12,000 | Publicly Announced | S | | | | Proposed | Water | 1,480 | | Apr 2023 | 28-03-2023",
"ai_summary": "Confirms the NEM generator record used by the user: Stage 2b is a proposed Hydro Tasmania pumped-hydro storage project in TAS1 with 750 MW and 12,000 MWh."
},
{
"field_name": "current_project_scope",
"value_text": "Cethana pumped hydro is Hydro Tasmania's preferred Battery of the Nation pumped-hydro project; 750 MW and 20 hours storage; construction phase about six to eight years with up to 400 workers at peak.",
"value_numeric": 750,
"unit": "MW",
"source_url": "https://connect.hydro.com.au/cethana-pumpedhydro",
"source_title": "Cethana pumped hydro project",
"publisher": "Hydro Tasmania / Connect Hydro",
"published_date": null,
"confidence": "high",
"raw_excerpt": "Lake Cethana in the Mersey-Forth scheme is Hydro Tasmania's preferred site for a proposed pumped hydro project. ... The project would have a generating capacity of 750 MW and a storage capacity of 20 hours. The construction phase would extend for approximately six to eight years with a construction workforce of up to 400 people (at the peak).",
"ai_summary": "Hydro Tasmania's current community project page indicates the active Cethana proposal is 750 MW and 20 hours, creating a mismatch with the 12,000 MWh Stage 2b generator record."
},
{
"field_name": "capex_total_aud",
"value_text": "Estimated by interpolating GHD 2025 PHES capital costs for 10-hour and 24-hour pumped hydro to 16 hours: $3.30M/MW at 10h and $4.08M/MW at 24h gives about $3.634M/MW; multiplied by 750 MW gives about $2.726B EPC construction cost including dedicated grid connection but excluding water purchase, owners' costs and financing.",
"value_numeric": 2725714286,
"unit": "AUD",
"source_url": "https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en",
"source_title": "2025 Energy Technology Cost and Technical Parameter Report",
"publisher": "GHD for AEMO",
"published_date": "2025-07-01",
"confidence": "medium",
"raw_excerpt": "Table 5.11 Development cost estimates – Pumped hydroelectric storage ... Relative cost – Power and storage component $/kW (Gross) 3,300 4,080 ... Total EPC cost $ 1,650,000,000 4,080,000,000 ... Exclusions ... Water purchase and procurement ... Transmission because the NSP will consider connection costs ... Owners’ costs and financing.",
"ai_summary": "Provides current AEMO/GHD pumped-hydro EPC cost parameters. Because no Stage 2b-specific final capex was found, a 16-hour estimate was derived from the 10h and 24h PHES cases."
},
{
"field_name": "capex_per_mw_aud",
"value_text": "Estimated 2025 capex intensity for a 16-hour pumped-hydro project: about $3.634M/MW, interpolated from GHD's $3.30M/MW 10-hour and $4.08M/MW 24-hour PHES cases.",
"value_numeric": 3634286,
"unit": "AUD/MW",
"source_url": "https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en",
"source_title": "2025 Energy Technology Cost and Technical Parameter Report",
"publisher": "GHD for AEMO",
"published_date": "2025-07-01",
"confidence": "medium",
"raw_excerpt": "Table 5.10 Average PHES power costs comparison: Duration 10, Average power cost $M/MW 3.30; Duration 24, Average power cost $M/MW 4.08. Table 5.11 ... Relative cost ... $/kW (Gross) 3,300 4,080.",
"ai_summary": "The capex intensity is an interpolated estimate, not a reported Hydro Tasmania construction budget."
},
{
"field_name": "capex_per_mwh_aud",
"value_text": "Estimated 2025 capex energy-intensity using the user's 12,000 MWh storage assumption: $2.7257B / 12,000 MWh = about $227,143/MWh.",
"value_numeric": 227143,
"unit": "AUD/MWh",
"source_url": "https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en",
"source_title": "2025 Energy Technology Cost and Technical Parameter Report",
"publisher": "GHD for AEMO",
"published_date": "2025-07-01",
"confidence": "medium",
"raw_excerpt": "Table 5.11 Development cost estimates – Pumped hydroelectric storage ... Relative cost – Power and storage component $/kW (Gross) 3,300 4,080 ... No additional storage cost ($/kWh) to be added.",
"ai_summary": "GHD expresses PHES capital cost mainly by $/kW and states no additional $/kWh storage cost should be added; the AUD/MWh metric here is a derived ratio for the requested schema."
},
{
"field_name": "old_reported_capex_cethana_prefeasibility",
"value_text": "2019 Hydro Tasmania prefeasibility estimate for the smaller Cethana option: 600 MW / about 6,700 MWh, 11 hours, $900 million total investment including contingency, about $1.50 million/MW installed, about 4.5-year construction schedule.",
"value_numeric": 900000000,
"unit": "AUD",
"source_url": "https://arena.gov.au/assets/2018/02/battery-of-the-nation-pumped-hydro-energy-storage-projects-prefeasibility-report.pdf",
"source_title": "Battery of the Nation – Pumped Hydro Energy Storage Projects Prefeasibility Studies Summary Report",
"publisher": "Hydro Tasmania / ARENA",
"published_date": "2019-08-30",
"confidence": "high",
"raw_excerpt": "The Cethana pumped hydro energy storage project ... would have an installed capacity of 600 MW and would have energy storage of about 6700 MWh (11 hours). ... Construction cost estimation for the project indicates a unit cost of approximately $1.50 million per MW installed and a total project investment of $900 million (including contingency).",
"ai_summary": "Historical nominal prefeasibility capex is preserved but not used as the main capex because the current project is larger and later cost benchmarks are materially higher."
},
{
"field_name": "capex_year_and_scope",
"value_text": "2025 estimate based on GHD/AEMO PHES EPC construction cost parameters; includes dedicated grid connection in Table 5.11, but excludes water purchase/procurement, owners' costs and financing; user-specified duration is 16 hours.",
"value_numeric": 2025,
"unit": "year",
"source_url": "https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en",
"source_title": "2025 Energy Technology Cost and Technical Parameter Report",
"publisher": "GHD for AEMO",
"published_date": "2025-07-01",
"confidence": "medium",
"raw_excerpt": "The purpose of this Report is to provide updated (as of 01 July 2025) input data regarding economic and technical parameters for AEMO ... Table 5.11 Development cost estimates – Pumped hydroelectric storage ... CAPEX construction (with dedicated grid connection) ... Exclusions ... Water purchase and procurement ... Owners’ costs and financing.",
"ai_summary": "Defines the year and scope of the estimated capex values used in this extraction."
},
{
"field_name": "fixed_opex_per_mw_year_aud",
"value_text": "Estimated fixed O&M for 16-hour PHES: about $21,071/MW/year, interpolated between GHD's 10-hour case at $20,000/MW/year and 24-hour case at $22,500/MW/year.",
"value_numeric": 21071,
"unit": "AUD/MW-year",
"source_url": "https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en",
"source_title": "2025 Energy Technology Cost and Technical Parameter Report",
"publisher": "GHD for AEMO",
"published_date": "2025-07-01",
"confidence": "medium",
"raw_excerpt": "Table 5.12 O&M cost estimates – Pumped hydroelectric storage ... Fixed O&M cost $/MW/year (Net) 20,000 22,500 25,000 30,000 ... Escalated from Entura (2018). Variable O&M cost ... Nil ... Included in fixed component.",
"ai_summary": "No Stage 2b-specific fixed O&M was found; the value is a duration-interpolated AEMO/GHD default."
},
{
"field_name": "fixed_opex_annual_aud",
"value_text": "Estimated annual fixed O&M for 750 MW at about $21,071/MW/year = about $15.8 million/year.",
"value_numeric": 15803571,
"unit": "AUD/year",
"source_url": "https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en",
"source_title": "2025 Energy Technology Cost and Technical Parameter Report",
"publisher": "GHD for AEMO",
"published_date": "2025-07-01",
"confidence": "medium",
"raw_excerpt": "Table 5.12 O&M cost estimates – Pumped hydroelectric storage ... Fixed O&M cost $/MW/year (Net) 20,000 22,500 ... Total annual O&M cost $ 10,000,000 22,500,000 ... Indicative annual average cost over operating life.",
"ai_summary": "Derived from interpolated fixed O&M intensity and the 750 MW capacity."
},
{
"field_name": "variable_opex_per_mwh_aud",
"value_text": "GHD/AEMO reports PHES variable O&M as nil/included in fixed O&M; Entura concluded variable O&M is not meaningful for hydropower projects.",
"value_numeric": 0,
"unit": "AUD/MWh",
"source_url": "https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en",
"source_title": "2025 Energy Technology Cost and Technical Parameter Report",
"publisher": "GHD for AEMO",
"published_date": "2025-07-01",
"confidence": "high",
"raw_excerpt": "Entura estimated O&M costs for PHES ... They concluded that variable O&M is not meaningful for hydropower projects ... fixed O&M costs only should be used ... Table 5.12 ... Variable O&M cost $/MWh (Net) Nil ... Included in fixed component.",
"ai_summary": "Variable O&M is set to zero for modelling because GHD/AEMO include PHES operating costs in fixed O&M."
},
{
"field_name": "fuel_contract_notes",
"value_text": "No fuel contract identified; pumped hydro pumps water uphill during off-peak/low-price periods and generates when demand/prices are high. Water is storage medium rather than fuel.",
"value_numeric": null,
"unit": null,
"source_url": "https://www.dcceew.gov.au/energy/renewable/pumped-hydro",
"source_title": "Pumped hydro",
"publisher": "Department of Climate Change, Energy, the Environment and Water",
"published_date": "2025-10-01",
"confidence": "high",
"raw_excerpt": "Pumped hydro operates ... two dams, one higher than the other, work in a cycle that pumps water into the upper reservoir during off-peak hours. Potential energy is then stored and generated when it’s needed. ... when prices are cheap ... water ... is pumped ... When both prices and demand are high, the water is released back into the lower reservoir.",
"ai_summary": "Supports treating fuel cost per GJ as not applicable; pumping electricity cost is market-dependent and not a fuel contract."
},
{
"field_name": "efficiency_pct",
"value_text": "Hydro Tasmania states the Cethana pumped-hydro project can be highly efficient with minimum cycle efficiency of approximately 76.4%.",
"value_numeric": 76.4,
"unit": "%",
"source_url": "https://www.hydro.com.au/articles/energy-industry/solving-problem-storage-transitioning-energy-market",
"source_title": "Solving the problem of storage in the transitioning energy market",
"publisher": "Hydro Tasmania",
"published_date": "2023-10-05",
"confidence": "high",
"raw_excerpt": "The elevation (drop) between the upper and lower storage together with the short distance between the storages mean the Cethana project can be highly efficient, with a minimum cycle efficiency of ~76.4%.",
"ai_summary": "Efficiency is treated as pumped-hydro round-trip/cycle efficiency, not thermal efficiency."
},
{
"field_name": "asset_life_years",
"value_text": "AEMO/GHD technical and economic/design life assumptions for pumped hydroelectric storage are 100 years across 10h, 24h, 48h and 160h cases.",
"value_numeric": 100,
"unit": "years",
"source_url": "https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en",
"source_title": "2025 Energy Technology Cost and Technical Parameter Report",
"publisher": "GHD for AEMO",
"published_date": "2025-07-01",
"confidence": "high",
"raw_excerpt": "Table 5.9 Technical parameters and project timeline – Pumped hydroelectric storage ... Economic / Design life Years 100 100 100 100 ... Technical life (Operational life) Years 100 100 100 100.",
"ai_summary": "Provides technology-default asset life used because no Stage 2b closure date or economic life was found."
},
{
"field_name": "emissions_intensity_tco2_mwh",
"value_text": "Direct operational emissions estimated at 0 tCO2/MWh for water-based pumped hydro storage; no fossil fuel combustion occurs on discharge. Lifecycle or pumping-energy emissions are not included.",
"value_numeric": 0,
"unit": "tCO2/MWh",
"source_url": "https://www.dcceew.gov.au/energy/renewable/pumped-hydro",
"source_title": "Pumped hydro",
"publisher": "Department of Climate Change, Energy, the Environment and Water",
"published_date": "2025-10-01",
"confidence": "medium",
"raw_excerpt": "In conventional hydroelectricity generation, water flows from a dam or reservoir where it has been stored and is then channelled through rotating turbines. These turbines then generate power. Pumped hydro operates on the same principle except that two dams ... work in a cycle that pumps water into the upper reservoir ...",
"ai_summary": "The source explains the water-cycle generation process. The zero direct-emissions value is an analyst assumption for operational emissions, excluding indirect emissions from pumping electricity."
},
{
"field_name": "major_refurbishment_or_closure_notes",
"value_text": "Project is not yet built; no closure date or refurbishment plan found. Current public updates indicate approvals and business-case work remain before a final investment decision.",
"value_numeric": null,
"unit": null,
"source_url": "https://www.hydro.com.au/sites/default/files/2026-01/Cethana%20project%20update%20December%202025.pdf",
"source_title": "Cethana Pumped Hydro Project Update - Issue 3, December 2025",
"publisher": "Hydro Tasmania",
"published_date": "2025-12-01",
"confidence": "high",
"raw_excerpt": "There is still a lot of work to do before a final investment decision will be made to proceed with delivering the project. ... approvals needed from all levels of Government ... We are working on our updated referral and will provide an update when there’s more information on next steps.",
"ai_summary": "Supports status as pre-FID/proposed with no closure or refurbishment notes because the project has not reached construction or operation."
},
{
"field_name": "approvals_status",
"value_text": "EPA Tasmania assessment commenced 6 March 2025; proposal includes a new 12 Mm3 storage, intake/discharge from Lake Cethana, underground pump/power station infrastructure, tunnels, transmission infrastructure, roads, power supply, spoil emplacements and temporary construction installations.",
"value_numeric": 12,
"unit": "Mm3",
"source_url": "https://epa.tas.gov.au/business-industry/assessment/proposals-assessed-by-the-ea/hydro-tasmania-cethana-phes-construction-works-lake-cethana",
"source_title": "Hydro Tasmania, Cethana PHES, Construction Works, Lake Cethana",
"publisher": "EPA Tasmania",
"published_date": "2025-03-06",
"confidence": "high",
"raw_excerpt": "Assessment Commenced: 6/3/2025 ... Hydro Tasmania is proposing to construct a Pumped Hydro Energy Storage facility at Lake Cethana. This will comprise a new 12 Mm3 storage, an intake / discharge from the Lake Cethana, underground pump/power station infrastructure, tunnels ... electricity transmission infrastructure ...",
"ai_summary": "Provides current official approvals context and construction scope."
}
],
"warnings": [
"No exact reported construction capex for Battery of the Nation - Stage 2b / current 750 MW configuration was found. Capex is estimated from AEMO/GHD 2025 PHES cost parameters, not presented as reported data.",
"The user-provided 750 MW / 12,000 MWh generator record conflicts with Hydro Tasmania's current Cethana public scope of 750 MW / 20 hours, approximately 15,000 MWh. The output follows the user's 12,000 MWh for capex_per_mwh and duration interpolation but notes the conflict.",
"Hydro Tasmania's historical 2019 Cethana prefeasibility capex of $900 million for 600 MW / 6,700 MWh is old nominal prefeasibility information and likely not comparable with a current FID-grade 750 MW project estimate.",
"Fuel cost per GJ and heat rate are not applicable to pumped hydro; the key variable input is electricity used for pumping, which is market-price dependent and not a fuel contract.",
"Emissions intensity is direct operational only. Indirect emissions from pumping energy depend on the grid electricity mix at pumping times and were not estimated."
]
}
{
"meta": {
"model": "gpt-5.5",
"reasoning_effort": "medium",
"response_id": "resp_019ecf89d3010d2a006a20ae8b407c8193b3d2c1c262123b55",
"fetched_at": "2026-06-04T08:47:42+10:00"
},
"raw_text": "{\"generator_identity\":{\"site_name\":\"Battery of the Nation - Stage 2b\",\"duid\":null,\"owner\":\"Hydro Tasmania\",\"region\":\"TAS1\",\"technology_type\":\"Storage - Pumped hydro\",\"fuel_type\":\"Hydro - Water\"},\"financial_profile\":{\"generator_type_normalised\":\"pumped_hydro\",\"capex_total_aud\":2725714286,\"capex_year\":2025,\"capex_basis\":\"estimated\",\"capex_per_mw_aud\":3634286,\"capex_per_mwh_aud\":227143,\"fixed_opex_annual_aud\":15803571,\"fixed_opex_per_mw_year_aud\":21071,\"variable_opex_per_mwh_aud\":0,\"fuel_cost_per_gj_aud\":null,\"fuel_contract_notes\":\"No fuel contract identified. Pumped hydro uses water as the storage medium; pumping energy is bought from the electricity market when demand/prices are low or renewable supply is abundant. This is an energy-arbitrage input rather than a fuel cost per GJ.\",\"heat_rate_gj_per_mwh\":null,\"efficiency_pct\":76.4,\"emissions_intensity_tco2_mwh\":0,\"asset_life_years\":100,\"discount_rate_pct\":null,\"source_confidence\":\"medium\",\"data_status\":\"partially_verified\",\"notes\":\"AEMO/NEM generator information identifies Battery of the Nation - Stage 2b as a 750 MW / 12,000 MWh proposed pumped-hydro project, but Hydro Tasmania's current public Cethana project materials describe the preferred Battery of the Nation pumped-hydro project as 750 MW with about 20 hours of storage, implying about 15,000 MWh. The capex and fixed opex values above are not reported project costs for Stage 2b; they are 2025 AUD estimates based on AEMO/GHD pumped-hydro cost parameters, linearly interpolated to the user's provided 16-hour duration between GHD's 10-hour and 24-hour PHES cases. Hydro Tasmania's 2019 prefeasibility Cethana option was smaller at 600 MW / 6,700 MWh and reported $900 million including contingency, about $1.5 million/MW, but this is old prefeasibility data and does not match the current 750 MW configuration. Current project status: still in approvals/business-case development; one EPBC referral was withdrawn in April 2025, but Hydro Tasmania's December 2025 update states it is working on an updated referral and that a final investment decision has not yet been made. No closure date was found; 100-year life is a technology assumption from AEMO/GHD for PHES.\"},\"sources\":[{\"field_name\":\"site_identity_capacity_status\",\"value_text\":\"Battery of the Nation - Stage 2b; owner Hydro Tasmania; storage - pumped hydro; Hydro - Water; 4 units; 187.50 MW each; 750 MW; 12,000 MWh; publicly announced; proposed.\",\"value_numeric\":750,\"unit\":\"MW\",\"source_url\":\"https://www.accc.gov.au/system/files/public-registers/documents/Luke%20Edwards%20Annexure%20%28LE-4%29%20-%2005.06.23%20-%20PR%20-%20MA1000024%20Brookfield%20Origin.pdf\",\"source_title\":\"Statement in support of application for merger authorisation - Annexure LE-4, AEMO Generation Information extract\",\"publisher\":\"ACCC / AEMO generation information extract\",\"published_date\":\"2023-06-05\",\"confidence\":\"medium\",\"raw_excerpt\":\"Existing Generation and New Developments TAS1 | Project | Battery of the Nation - Stage 2b | Hydro Tasmania | Storage - Pumped hydro | Hydro - Water | | 4 | | 187.50 | | 750 | 750 | 12,000 | Publicly Announced | S | | | | Proposed | Water | 1,480 | | Apr 2023 | 28-03-2023\",\"ai_summary\":\"Confirms the NEM generator record used by the user: Stage 2b is a proposed Hydro Tasmania pumped-hydro storage project in TAS1 with 750 MW and 12,000 MWh.\"},{\"field_name\":\"current_project_scope\",\"value_text\":\"Cethana pumped hydro is Hydro Tasmania's preferred Battery of the Nation pumped-hydro project; 750 MW and 20 hours storage; construction phase about six to eight years with up to 400 workers at peak.\",\"value_numeric\":750,\"unit\":\"MW\",\"source_url\":\"https://connect.hydro.com.au/cethana-pumpedhydro\",\"source_title\":\"Cethana pumped hydro project\",\"publisher\":\"Hydro Tasmania / Connect Hydro\",\"published_date\":null,\"confidence\":\"high\",\"raw_excerpt\":\"Lake Cethana in the Mersey-Forth scheme is Hydro Tasmania's preferred site for a proposed pumped hydro project. ... The project would have a generating capacity of 750 MW and a storage capacity of 20 hours. The construction phase would extend for approximately six to eight years with a construction workforce of up to 400 people (at the peak).\",\"ai_summary\":\"Hydro Tasmania's current community project page indicates the active Cethana proposal is 750 MW and 20 hours, creating a mismatch with the 12,000 MWh Stage 2b generator record.\"},{\"field_name\":\"capex_total_aud\",\"value_text\":\"Estimated by interpolating GHD 2025 PHES capital costs for 10-hour and 24-hour pumped hydro to 16 hours: $3.30M/MW at 10h and $4.08M/MW at 24h gives about $3.634M/MW; multiplied by 750 MW gives about $2.726B EPC construction cost including dedicated grid connection but excluding water purchase, owners' costs and financing.\",\"value_numeric\":2725714286,\"unit\":\"AUD\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"medium\",\"raw_excerpt\":\"Table 5.11 Development cost estimates – Pumped hydroelectric storage ... Relative cost – Power and storage component $/kW (Gross) 3,300 4,080 ... Total EPC cost $ 1,650,000,000 4,080,000,000 ... Exclusions ... Water purchase and procurement ... Transmission because the NSP will consider connection costs ... Owners’ costs and financing.\",\"ai_summary\":\"Provides current AEMO/GHD pumped-hydro EPC cost parameters. Because no Stage 2b-specific final capex was found, a 16-hour estimate was derived from the 10h and 24h PHES cases.\"},{\"field_name\":\"capex_per_mw_aud\",\"value_text\":\"Estimated 2025 capex intensity for a 16-hour pumped-hydro project: about $3.634M/MW, interpolated from GHD's $3.30M/MW 10-hour and $4.08M/MW 24-hour PHES cases.\",\"value_numeric\":3634286,\"unit\":\"AUD/MW\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"medium\",\"raw_excerpt\":\"Table 5.10 Average PHES power costs comparison: Duration 10, Average power cost $M/MW 3.30; Duration 24, Average power cost $M/MW 4.08. Table 5.11 ... Relative cost ... $/kW (Gross) 3,300 4,080.\",\"ai_summary\":\"The capex intensity is an interpolated estimate, not a reported Hydro Tasmania construction budget.\"},{\"field_name\":\"capex_per_mwh_aud\",\"value_text\":\"Estimated 2025 capex energy-intensity using the user's 12,000 MWh storage assumption: $2.7257B / 12,000 MWh = about $227,143/MWh.\",\"value_numeric\":227143,\"unit\":\"AUD/MWh\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"medium\",\"raw_excerpt\":\"Table 5.11 Development cost estimates – Pumped hydroelectric storage ... Relative cost – Power and storage component $/kW (Gross) 3,300 4,080 ... No additional storage cost ($/kWh) to be added.\",\"ai_summary\":\"GHD expresses PHES capital cost mainly by $/kW and states no additional $/kWh storage cost should be added; the AUD/MWh metric here is a derived ratio for the requested schema.\"},{\"field_name\":\"old_reported_capex_cethana_prefeasibility\",\"value_text\":\"2019 Hydro Tasmania prefeasibility estimate for the smaller Cethana option: 600 MW / about 6,700 MWh, 11 hours, $900 million total investment including contingency, about $1.50 million/MW installed, about 4.5-year construction schedule.\",\"value_numeric\":900000000,\"unit\":\"AUD\",\"source_url\":\"https://arena.gov.au/assets/2018/02/battery-of-the-nation-pumped-hydro-energy-storage-projects-prefeasibility-report.pdf\",\"source_title\":\"Battery of the Nation – Pumped Hydro Energy Storage Projects Prefeasibility Studies Summary Report\",\"publisher\":\"Hydro Tasmania / ARENA\",\"published_date\":\"2019-08-30\",\"confidence\":\"high\",\"raw_excerpt\":\"The Cethana pumped hydro energy storage project ... would have an installed capacity of 600 MW and would have energy storage of about 6700 MWh (11 hours). ... Construction cost estimation for the project indicates a unit cost of approximately $1.50 million per MW installed and a total project investment of $900 million (including contingency).\",\"ai_summary\":\"Historical nominal prefeasibility capex is preserved but not used as the main capex because the current project is larger and later cost benchmarks are materially higher.\"},{\"field_name\":\"capex_year_and_scope\",\"value_text\":\"2025 estimate based on GHD/AEMO PHES EPC construction cost parameters; includes dedicated grid connection in Table 5.11, but excludes water purchase/procurement, owners' costs and financing; user-specified duration is 16 hours.\",\"value_numeric\":2025,\"unit\":\"year\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"medium\",\"raw_excerpt\":\"The purpose of this Report is to provide updated (as of 01 July 2025) input data regarding economic and technical parameters for AEMO ... Table 5.11 Development cost estimates – Pumped hydroelectric storage ... CAPEX construction (with dedicated grid connection) ... Exclusions ... Water purchase and procurement ... Owners’ costs and financing.\",\"ai_summary\":\"Defines the year and scope of the estimated capex values used in this extraction.\"},{\"field_name\":\"fixed_opex_per_mw_year_aud\",\"value_text\":\"Estimated fixed O&M for 16-hour PHES: about $21,071/MW/year, interpolated between GHD's 10-hour case at $20,000/MW/year and 24-hour case at $22,500/MW/year.\",\"value_numeric\":21071,\"unit\":\"AUD/MW-year\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"medium\",\"raw_excerpt\":\"Table 5.12 O&M cost estimates – Pumped hydroelectric storage ... Fixed O&M cost $/MW/year (Net) 20,000 22,500 25,000 30,000 ... Escalated from Entura (2018). Variable O&M cost ... Nil ... Included in fixed component.\",\"ai_summary\":\"No Stage 2b-specific fixed O&M was found; the value is a duration-interpolated AEMO/GHD default.\"},{\"field_name\":\"fixed_opex_annual_aud\",\"value_text\":\"Estimated annual fixed O&M for 750 MW at about $21,071/MW/year = about $15.8 million/year.\",\"value_numeric\":15803571,\"unit\":\"AUD/year\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"medium\",\"raw_excerpt\":\"Table 5.12 O&M cost estimates – Pumped hydroelectric storage ... Fixed O&M cost $/MW/year (Net) 20,000 22,500 ... Total annual O&M cost $ 10,000,000 22,500,000 ... Indicative annual average cost over operating life.\",\"ai_summary\":\"Derived from interpolated fixed O&M intensity and the 750 MW capacity.\"},{\"field_name\":\"variable_opex_per_mwh_aud\",\"value_text\":\"GHD/AEMO reports PHES variable O&M as nil/included in fixed O&M; Entura concluded variable O&M is not meaningful for hydropower projects.\",\"value_numeric\":0,\"unit\":\"AUD/MWh\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"high\",\"raw_excerpt\":\"Entura estimated O&M costs for PHES ... They concluded that variable O&M is not meaningful for hydropower projects ... fixed O&M costs only should be used ... Table 5.12 ... Variable O&M cost $/MWh (Net) Nil ... Included in fixed component.\",\"ai_summary\":\"Variable O&M is set to zero for modelling because GHD/AEMO include PHES operating costs in fixed O&M.\"},{\"field_name\":\"fuel_contract_notes\",\"value_text\":\"No fuel contract identified; pumped hydro pumps water uphill during off-peak/low-price periods and generates when demand/prices are high. Water is storage medium rather than fuel.\",\"value_numeric\":null,\"unit\":null,\"source_url\":\"https://www.dcceew.gov.au/energy/renewable/pumped-hydro\",\"source_title\":\"Pumped hydro\",\"publisher\":\"Department of Climate Change, Energy, the Environment and Water\",\"published_date\":\"2025-10-01\",\"confidence\":\"high\",\"raw_excerpt\":\"Pumped hydro operates ... two dams, one higher than the other, work in a cycle that pumps water into the upper reservoir during off-peak hours. Potential energy is then stored and generated when it’s needed. ... when prices are cheap ... water ... is pumped ... When both prices and demand are high, the water is released back into the lower reservoir.\",\"ai_summary\":\"Supports treating fuel cost per GJ as not applicable; pumping electricity cost is market-dependent and not a fuel contract.\"},{\"field_name\":\"efficiency_pct\",\"value_text\":\"Hydro Tasmania states the Cethana pumped-hydro project can be highly efficient with minimum cycle efficiency of approximately 76.4%.\",\"value_numeric\":76.4,\"unit\":\"%\",\"source_url\":\"https://www.hydro.com.au/articles/energy-industry/solving-problem-storage-transitioning-energy-market\",\"source_title\":\"Solving the problem of storage in the transitioning energy market\",\"publisher\":\"Hydro Tasmania\",\"published_date\":\"2023-10-05\",\"confidence\":\"high\",\"raw_excerpt\":\"The elevation (drop) between the upper and lower storage together with the short distance between the storages mean the Cethana project can be highly efficient, with a minimum cycle efficiency of ~76.4%.\",\"ai_summary\":\"Efficiency is treated as pumped-hydro round-trip/cycle efficiency, not thermal efficiency.\"},{\"field_name\":\"asset_life_years\",\"value_text\":\"AEMO/GHD technical and economic/design life assumptions for pumped hydroelectric storage are 100 years across 10h, 24h, 48h and 160h cases.\",\"value_numeric\":100,\"unit\":\"years\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"high\",\"raw_excerpt\":\"Table 5.9 Technical parameters and project timeline – Pumped hydroelectric storage ... Economic / Design life Years 100 100 100 100 ... Technical life (Operational life) Years 100 100 100 100.\",\"ai_summary\":\"Provides technology-default asset life used because no Stage 2b closure date or economic life was found.\"},{\"field_name\":\"emissions_intensity_tco2_mwh\",\"value_text\":\"Direct operational emissions estimated at 0 tCO2/MWh for water-based pumped hydro storage; no fossil fuel combustion occurs on discharge. Lifecycle or pumping-energy emissions are not included.\",\"value_numeric\":0,\"unit\":\"tCO2/MWh\",\"source_url\":\"https://www.dcceew.gov.au/energy/renewable/pumped-hydro\",\"source_title\":\"Pumped hydro\",\"publisher\":\"Department of Climate Change, Energy, the Environment and Water\",\"published_date\":\"2025-10-01\",\"confidence\":\"medium\",\"raw_excerpt\":\"In conventional hydroelectricity generation, water flows from a dam or reservoir where it has been stored and is then channelled through rotating turbines. These turbines then generate power. Pumped hydro operates on the same principle except that two dams ... work in a cycle that pumps water into the upper reservoir ...\",\"ai_summary\":\"The source explains the water-cycle generation process. The zero direct-emissions value is an analyst assumption for operational emissions, excluding indirect emissions from pumping electricity.\"},{\"field_name\":\"major_refurbishment_or_closure_notes\",\"value_text\":\"Project is not yet built; no closure date or refurbishment plan found. Current public updates indicate approvals and business-case work remain before a final investment decision.\",\"value_numeric\":null,\"unit\":null,\"source_url\":\"https://www.hydro.com.au/sites/default/files/2026-01/Cethana%20project%20update%20December%202025.pdf\",\"source_title\":\"Cethana Pumped Hydro Project Update - Issue 3, December 2025\",\"publisher\":\"Hydro Tasmania\",\"published_date\":\"2025-12-01\",\"confidence\":\"high\",\"raw_excerpt\":\"There is still a lot of work to do before a final investment decision will be made to proceed with delivering the project. ... approvals needed from all levels of Government ... We are working on our updated referral and will provide an update when there’s more information on next steps.\",\"ai_summary\":\"Supports status as pre-FID/proposed with no closure or refurbishment notes because the project has not reached construction or operation.\"},{\"field_name\":\"approvals_status\",\"value_text\":\"EPA Tasmania assessment commenced 6 March 2025; proposal includes a new 12 Mm3 storage, intake/discharge from Lake Cethana, underground pump/power station infrastructure, tunnels, transmission infrastructure, roads, power supply, spoil emplacements and temporary construction installations.\",\"value_numeric\":12,\"unit\":\"Mm3\",\"source_url\":\"https://epa.tas.gov.au/business-industry/assessment/proposals-assessed-by-the-ea/hydro-tasmania-cethana-phes-construction-works-lake-cethana\",\"source_title\":\"Hydro Tasmania, Cethana PHES, Construction Works, Lake Cethana\",\"publisher\":\"EPA Tasmania\",\"published_date\":\"2025-03-06\",\"confidence\":\"high\",\"raw_excerpt\":\"Assessment Commenced: 6/3/2025 ... Hydro Tasmania is proposing to construct a Pumped Hydro Energy Storage facility at Lake Cethana. This will comprise a new 12 Mm3 storage, an intake / discharge from the Lake Cethana, underground pump/power station infrastructure, tunnels ... electricity transmission infrastructure ...\",\"ai_summary\":\"Provides current official approvals context and construction scope.\"}],\"warnings\":[\"No exact reported construction capex for Battery of the Nation - Stage 2b / current 750 MW configuration was found. Capex is estimated from AEMO/GHD 2025 PHES cost parameters, not presented as reported data.\",\"The user-provided 750 MW / 12,000 MWh generator record conflicts with Hydro Tasmania's current Cethana public scope of 750 MW / 20 hours, approximately 15,000 MWh. The output follows the user's 12,000 MWh for capex_per_mwh and duration interpolation but notes the conflict.\",\"Hydro Tasmania's historical 2019 Cethana prefeasibility capex of $900 million for 600 MW / 6,700 MWh is old nominal prefeasibility information and likely not comparable with a current FID-grade 750 MW project estimate.\",\"Fuel cost per GJ and heat rate are not applicable to pumped hydro; the key variable input is electricity used for pumping, which is market-price dependent and not a fuel contract.\",\"Emissions intensity is direct operational only. Indirect emissions from pumping energy depend on the grid electricity mix at pumping times and were not estimated.\"]}",
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"text": "{\"generator_identity\":{\"site_name\":\"Battery of the Nation - Stage 2b\",\"duid\":null,\"owner\":\"Hydro Tasmania\",\"region\":\"TAS1\",\"technology_type\":\"Storage - Pumped hydro\",\"fuel_type\":\"Hydro - Water\"},\"financial_profile\":{\"generator_type_normalised\":\"pumped_hydro\",\"capex_total_aud\":2725714286,\"capex_year\":2025,\"capex_basis\":\"estimated\",\"capex_per_mw_aud\":3634286,\"capex_per_mwh_aud\":227143,\"fixed_opex_annual_aud\":15803571,\"fixed_opex_per_mw_year_aud\":21071,\"variable_opex_per_mwh_aud\":0,\"fuel_cost_per_gj_aud\":null,\"fuel_contract_notes\":\"No fuel contract identified. Pumped hydro uses water as the storage medium; pumping energy is bought from the electricity market when demand/prices are low or renewable supply is abundant. This is an energy-arbitrage input rather than a fuel cost per GJ.\",\"heat_rate_gj_per_mwh\":null,\"efficiency_pct\":76.4,\"emissions_intensity_tco2_mwh\":0,\"asset_life_years\":100,\"discount_rate_pct\":null,\"source_confidence\":\"medium\",\"data_status\":\"partially_verified\",\"notes\":\"AEMO/NEM generator information identifies Battery of the Nation - Stage 2b as a 750 MW / 12,000 MWh proposed pumped-hydro project, but Hydro Tasmania's current public Cethana project materials describe the preferred Battery of the Nation pumped-hydro project as 750 MW with about 20 hours of storage, implying about 15,000 MWh. The capex and fixed opex values above are not reported project costs for Stage 2b; they are 2025 AUD estimates based on AEMO/GHD pumped-hydro cost parameters, linearly interpolated to the user's provided 16-hour duration between GHD's 10-hour and 24-hour PHES cases. Hydro Tasmania's 2019 prefeasibility Cethana option was smaller at 600 MW / 6,700 MWh and reported $900 million including contingency, about $1.5 million/MW, but this is old prefeasibility data and does not match the current 750 MW configuration. Current project status: still in approvals/business-case development; one EPBC referral was withdrawn in April 2025, but Hydro Tasmania's December 2025 update states it is working on an updated referral and that a final investment decision has not yet been made. No closure date was found; 100-year life is a technology assumption from AEMO/GHD for PHES.\"},\"sources\":[{\"field_name\":\"site_identity_capacity_status\",\"value_text\":\"Battery of the Nation - Stage 2b; owner Hydro Tasmania; storage - pumped hydro; Hydro - Water; 4 units; 187.50 MW each; 750 MW; 12,000 MWh; publicly announced; proposed.\",\"value_numeric\":750,\"unit\":\"MW\",\"source_url\":\"https://www.accc.gov.au/system/files/public-registers/documents/Luke%20Edwards%20Annexure%20%28LE-4%29%20-%2005.06.23%20-%20PR%20-%20MA1000024%20Brookfield%20Origin.pdf\",\"source_title\":\"Statement in support of application for merger authorisation - Annexure LE-4, AEMO Generation Information extract\",\"publisher\":\"ACCC / AEMO generation information extract\",\"published_date\":\"2023-06-05\",\"confidence\":\"medium\",\"raw_excerpt\":\"Existing Generation and New Developments TAS1 | Project | Battery of the Nation - Stage 2b | Hydro Tasmania | Storage - Pumped hydro | Hydro - Water | | 4 | | 187.50 | | 750 | 750 | 12,000 | Publicly Announced | S | | | | Proposed | Water | 1,480 | | Apr 2023 | 28-03-2023\",\"ai_summary\":\"Confirms the NEM generator record used by the user: Stage 2b is a proposed Hydro Tasmania pumped-hydro storage project in TAS1 with 750 MW and 12,000 MWh.\"},{\"field_name\":\"current_project_scope\",\"value_text\":\"Cethana pumped hydro is Hydro Tasmania's preferred Battery of the Nation pumped-hydro project; 750 MW and 20 hours storage; construction phase about six to eight years with up to 400 workers at peak.\",\"value_numeric\":750,\"unit\":\"MW\",\"source_url\":\"https://connect.hydro.com.au/cethana-pumpedhydro\",\"source_title\":\"Cethana pumped hydro project\",\"publisher\":\"Hydro Tasmania / Connect Hydro\",\"published_date\":null,\"confidence\":\"high\",\"raw_excerpt\":\"Lake Cethana in the Mersey-Forth scheme is Hydro Tasmania's preferred site for a proposed pumped hydro project. ... The project would have a generating capacity of 750 MW and a storage capacity of 20 hours. The construction phase would extend for approximately six to eight years with a construction workforce of up to 400 people (at the peak).\",\"ai_summary\":\"Hydro Tasmania's current community project page indicates the active Cethana proposal is 750 MW and 20 hours, creating a mismatch with the 12,000 MWh Stage 2b generator record.\"},{\"field_name\":\"capex_total_aud\",\"value_text\":\"Estimated by interpolating GHD 2025 PHES capital costs for 10-hour and 24-hour pumped hydro to 16 hours: $3.30M/MW at 10h and $4.08M/MW at 24h gives about $3.634M/MW; multiplied by 750 MW gives about $2.726B EPC construction cost including dedicated grid connection but excluding water purchase, owners' costs and financing.\",\"value_numeric\":2725714286,\"unit\":\"AUD\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"medium\",\"raw_excerpt\":\"Table 5.11 Development cost estimates – Pumped hydroelectric storage ... Relative cost – Power and storage component $/kW (Gross) 3,300 4,080 ... Total EPC cost $ 1,650,000,000 4,080,000,000 ... Exclusions ... Water purchase and procurement ... Transmission because the NSP will consider connection costs ... Owners’ costs and financing.\",\"ai_summary\":\"Provides current AEMO/GHD pumped-hydro EPC cost parameters. Because no Stage 2b-specific final capex was found, a 16-hour estimate was derived from the 10h and 24h PHES cases.\"},{\"field_name\":\"capex_per_mw_aud\",\"value_text\":\"Estimated 2025 capex intensity for a 16-hour pumped-hydro project: about $3.634M/MW, interpolated from GHD's $3.30M/MW 10-hour and $4.08M/MW 24-hour PHES cases.\",\"value_numeric\":3634286,\"unit\":\"AUD/MW\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"medium\",\"raw_excerpt\":\"Table 5.10 Average PHES power costs comparison: Duration 10, Average power cost $M/MW 3.30; Duration 24, Average power cost $M/MW 4.08. Table 5.11 ... Relative cost ... $/kW (Gross) 3,300 4,080.\",\"ai_summary\":\"The capex intensity is an interpolated estimate, not a reported Hydro Tasmania construction budget.\"},{\"field_name\":\"capex_per_mwh_aud\",\"value_text\":\"Estimated 2025 capex energy-intensity using the user's 12,000 MWh storage assumption: $2.7257B / 12,000 MWh = about $227,143/MWh.\",\"value_numeric\":227143,\"unit\":\"AUD/MWh\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"medium\",\"raw_excerpt\":\"Table 5.11 Development cost estimates – Pumped hydroelectric storage ... Relative cost – Power and storage component $/kW (Gross) 3,300 4,080 ... No additional storage cost ($/kWh) to be added.\",\"ai_summary\":\"GHD expresses PHES capital cost mainly by $/kW and states no additional $/kWh storage cost should be added; the AUD/MWh metric here is a derived ratio for the requested schema.\"},{\"field_name\":\"old_reported_capex_cethana_prefeasibility\",\"value_text\":\"2019 Hydro Tasmania prefeasibility estimate for the smaller Cethana option: 600 MW / about 6,700 MWh, 11 hours, $900 million total investment including contingency, about $1.50 million/MW installed, about 4.5-year construction schedule.\",\"value_numeric\":900000000,\"unit\":\"AUD\",\"source_url\":\"https://arena.gov.au/assets/2018/02/battery-of-the-nation-pumped-hydro-energy-storage-projects-prefeasibility-report.pdf\",\"source_title\":\"Battery of the Nation – Pumped Hydro Energy Storage Projects Prefeasibility Studies Summary Report\",\"publisher\":\"Hydro Tasmania / ARENA\",\"published_date\":\"2019-08-30\",\"confidence\":\"high\",\"raw_excerpt\":\"The Cethana pumped hydro energy storage project ... would have an installed capacity of 600 MW and would have energy storage of about 6700 MWh (11 hours). ... Construction cost estimation for the project indicates a unit cost of approximately $1.50 million per MW installed and a total project investment of $900 million (including contingency).\",\"ai_summary\":\"Historical nominal prefeasibility capex is preserved but not used as the main capex because the current project is larger and later cost benchmarks are materially higher.\"},{\"field_name\":\"capex_year_and_scope\",\"value_text\":\"2025 estimate based on GHD/AEMO PHES EPC construction cost parameters; includes dedicated grid connection in Table 5.11, but excludes water purchase/procurement, owners' costs and financing; user-specified duration is 16 hours.\",\"value_numeric\":2025,\"unit\":\"year\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"medium\",\"raw_excerpt\":\"The purpose of this Report is to provide updated (as of 01 July 2025) input data regarding economic and technical parameters for AEMO ... Table 5.11 Development cost estimates – Pumped hydroelectric storage ... CAPEX construction (with dedicated grid connection) ... Exclusions ... Water purchase and procurement ... Owners’ costs and financing.\",\"ai_summary\":\"Defines the year and scope of the estimated capex values used in this extraction.\"},{\"field_name\":\"fixed_opex_per_mw_year_aud\",\"value_text\":\"Estimated fixed O&M for 16-hour PHES: about $21,071/MW/year, interpolated between GHD's 10-hour case at $20,000/MW/year and 24-hour case at $22,500/MW/year.\",\"value_numeric\":21071,\"unit\":\"AUD/MW-year\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"medium\",\"raw_excerpt\":\"Table 5.12 O&M cost estimates – Pumped hydroelectric storage ... Fixed O&M cost $/MW/year (Net) 20,000 22,500 25,000 30,000 ... Escalated from Entura (2018). Variable O&M cost ... Nil ... Included in fixed component.\",\"ai_summary\":\"No Stage 2b-specific fixed O&M was found; the value is a duration-interpolated AEMO/GHD default.\"},{\"field_name\":\"fixed_opex_annual_aud\",\"value_text\":\"Estimated annual fixed O&M for 750 MW at about $21,071/MW/year = about $15.8 million/year.\",\"value_numeric\":15803571,\"unit\":\"AUD/year\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"medium\",\"raw_excerpt\":\"Table 5.12 O&M cost estimates – Pumped hydroelectric storage ... Fixed O&M cost $/MW/year (Net) 20,000 22,500 ... Total annual O&M cost $ 10,000,000 22,500,000 ... Indicative annual average cost over operating life.\",\"ai_summary\":\"Derived from interpolated fixed O&M intensity and the 750 MW capacity.\"},{\"field_name\":\"variable_opex_per_mwh_aud\",\"value_text\":\"GHD/AEMO reports PHES variable O&M as nil/included in fixed O&M; Entura concluded variable O&M is not meaningful for hydropower projects.\",\"value_numeric\":0,\"unit\":\"AUD/MWh\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"high\",\"raw_excerpt\":\"Entura estimated O&M costs for PHES ... They concluded that variable O&M is not meaningful for hydropower projects ... fixed O&M costs only should be used ... Table 5.12 ... Variable O&M cost $/MWh (Net) Nil ... Included in fixed component.\",\"ai_summary\":\"Variable O&M is set to zero for modelling because GHD/AEMO include PHES operating costs in fixed O&M.\"},{\"field_name\":\"fuel_contract_notes\",\"value_text\":\"No fuel contract identified; pumped hydro pumps water uphill during off-peak/low-price periods and generates when demand/prices are high. Water is storage medium rather than fuel.\",\"value_numeric\":null,\"unit\":null,\"source_url\":\"https://www.dcceew.gov.au/energy/renewable/pumped-hydro\",\"source_title\":\"Pumped hydro\",\"publisher\":\"Department of Climate Change, Energy, the Environment and Water\",\"published_date\":\"2025-10-01\",\"confidence\":\"high\",\"raw_excerpt\":\"Pumped hydro operates ... two dams, one higher than the other, work in a cycle that pumps water into the upper reservoir during off-peak hours. Potential energy is then stored and generated when it’s needed. ... when prices are cheap ... water ... is pumped ... When both prices and demand are high, the water is released back into the lower reservoir.\",\"ai_summary\":\"Supports treating fuel cost per GJ as not applicable; pumping electricity cost is market-dependent and not a fuel contract.\"},{\"field_name\":\"efficiency_pct\",\"value_text\":\"Hydro Tasmania states the Cethana pumped-hydro project can be highly efficient with minimum cycle efficiency of approximately 76.4%.\",\"value_numeric\":76.4,\"unit\":\"%\",\"source_url\":\"https://www.hydro.com.au/articles/energy-industry/solving-problem-storage-transitioning-energy-market\",\"source_title\":\"Solving the problem of storage in the transitioning energy market\",\"publisher\":\"Hydro Tasmania\",\"published_date\":\"2023-10-05\",\"confidence\":\"high\",\"raw_excerpt\":\"The elevation (drop) between the upper and lower storage together with the short distance between the storages mean the Cethana project can be highly efficient, with a minimum cycle efficiency of ~76.4%.\",\"ai_summary\":\"Efficiency is treated as pumped-hydro round-trip/cycle efficiency, not thermal efficiency.\"},{\"field_name\":\"asset_life_years\",\"value_text\":\"AEMO/GHD technical and economic/design life assumptions for pumped hydroelectric storage are 100 years across 10h, 24h, 48h and 160h cases.\",\"value_numeric\":100,\"unit\":\"years\",\"source_url\":\"https://www.aemo.com.au/-/media/files/stakeholder_consultation/consultations/nem-consultations/2025/draft-2026-fau/ghd-2025-energy-technology-cost-and-technical-parameter-report.pdf?rev=4951107dc12e4fddb32c8a96ba47bcc5&sc_lang=en\",\"source_title\":\"2025 Energy Technology Cost and Technical Parameter Report\",\"publisher\":\"GHD for AEMO\",\"published_date\":\"2025-07-01\",\"confidence\":\"high\",\"raw_excerpt\":\"Table 5.9 Technical parameters and project timeline – Pumped hydroelectric storage ... Economic / Design life Years 100 100 100 100 ... Technical life (Operational life) Years 100 100 100 100.\",\"ai_summary\":\"Provides technology-default asset life used because no Stage 2b closure date or economic life was found.\"},{\"field_name\":\"emissions_intensity_tco2_mwh\",\"value_text\":\"Direct operational emissions estimated at 0 tCO2/MWh for water-based pumped hydro storage; no fossil fuel combustion occurs on discharge. Lifecycle or pumping-energy emissions are not included.\",\"value_numeric\":0,\"unit\":\"tCO2/MWh\",\"source_url\":\"https://www.dcceew.gov.au/energy/renewable/pumped-hydro\",\"source_title\":\"Pumped hydro\",\"publisher\":\"Department of Climate Change, Energy, the Environment and Water\",\"published_date\":\"2025-10-01\",\"confidence\":\"medium\",\"raw_excerpt\":\"In conventional hydroelectricity generation, water flows from a dam or reservoir where it has been stored and is then channelled through rotating turbines. These turbines then generate power. Pumped hydro operates on the same principle except that two dams ... work in a cycle that pumps water into the upper reservoir ...\",\"ai_summary\":\"The source explains the water-cycle generation process. The zero direct-emissions value is an analyst assumption for operational emissions, excluding indirect emissions from pumping electricity.\"},{\"field_name\":\"major_refurbishment_or_closure_notes\",\"value_text\":\"Project is not yet built; no closure date or refurbishment plan found. Current public updates indicate approvals and business-case work remain before a final investment decision.\",\"value_numeric\":null,\"unit\":null,\"source_url\":\"https://www.hydro.com.au/sites/default/files/2026-01/Cethana%20project%20update%20December%202025.pdf\",\"source_title\":\"Cethana Pumped Hydro Project Update - Issue 3, December 2025\",\"publisher\":\"Hydro Tasmania\",\"published_date\":\"2025-12-01\",\"confidence\":\"high\",\"raw_excerpt\":\"There is still a lot of work to do before a final investment decision will be made to proceed with delivering the project. ... approvals needed from all levels of Government ... We are working on our updated referral and will provide an update when there’s more information on next steps.\",\"ai_summary\":\"Supports status as pre-FID/proposed with no closure or refurbishment notes because the project has not reached construction or operation.\"},{\"field_name\":\"approvals_status\",\"value_text\":\"EPA Tasmania assessment commenced 6 March 2025; proposal includes a new 12 Mm3 storage, intake/discharge from Lake Cethana, underground pump/power station infrastructure, tunnels, transmission infrastructure, roads, power supply, spoil emplacements and temporary construction installations.\",\"value_numeric\":12,\"unit\":\"Mm3\",\"source_url\":\"https://epa.tas.gov.au/business-industry/assessment/proposals-assessed-by-the-ea/hydro-tasmania-cethana-phes-construction-works-lake-cethana\",\"source_title\":\"Hydro Tasmania, Cethana PHES, Construction Works, Lake Cethana\",\"publisher\":\"EPA Tasmania\",\"published_date\":\"2025-03-06\",\"confidence\":\"high\",\"raw_excerpt\":\"Assessment Commenced: 6/3/2025 ... Hydro Tasmania is proposing to construct a Pumped Hydro Energy Storage facility at Lake Cethana. This will comprise a new 12 Mm3 storage, an intake / discharge from the Lake Cethana, underground pump/power station infrastructure, tunnels ... electricity transmission infrastructure ...\",\"ai_summary\":\"Provides current official approvals context and construction scope.\"}],\"warnings\":[\"No exact reported construction capex for Battery of the Nation - Stage 2b / current 750 MW configuration was found. Capex is estimated from AEMO/GHD 2025 PHES cost parameters, not presented as reported data.\",\"The user-provided 750 MW / 12,000 MWh generator record conflicts with Hydro Tasmania's current Cethana public scope of 750 MW / 20 hours, approximately 15,000 MWh. The output follows the user's 12,000 MWh for capex_per_mwh and duration interpolation but notes the conflict.\",\"Hydro Tasmania's historical 2019 Cethana prefeasibility capex of $900 million for 600 MW / 6,700 MWh is old nominal prefeasibility information and likely not comparable with a current FID-grade 750 MW project estimate.\",\"Fuel cost per GJ and heat rate are not applicable to pumped hydro; the key variable input is electricity used for pumping, which is market-price dependent and not a fuel contract.\",\"Emissions intensity is direct operational only. Indirect emissions from pumping energy depend on the grid electricity mix at pumping times and were not estimated.\"]}"
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