Use-Case / TCO — Airport GSE Solar 300 kWp (AU)

Verdict: NPV = AUD 1,233,185 (positive) over a 25-year horizon at a 7.00% discount rate; simple payback 3.28 yr, discounted payback 3.84 yr; LCOE AUD 0.0886/kWh. Equipment: 518 × LONGi Hi-MO 7 LR7-72HGD bifacial modules on Schletter Fix Z-Prof mounting, 2 × Sungrow SG125HT three-phase string inverters (250 kW AC total). Location: Australian regional airport (Ausgrid distribution area, NSW). Horizon: 25 years. Discount rate: 7.00% nominal. Evidence date: 2024-11-15. Limitation: site-specific specific-yield (1,580 kWh/kWp/yr) is a bounded model assumption; replace with a Solcast / PVsyst site simulation before financial close.

Decision summary (computed)
Metric	Value
Currency	AUD (nominal)
Horizon (years)	25
Discount rate	7.00 %
Total undiscounted cost (AUD)	591,170.44
Total discounted cost / PV of costs (AUD)	469,477.90
Total undiscounted benefit (AUD)	3,972,941.68
Total discounted benefit (AUD)	1,702,662.73
NPV (AUD)	1,233,184.83
IRR	0.3193
Simple payback (year)	3.28
Discounted payback (year)	3.84
LCOE (AUD/kWh)	0.0886

1. Inputs Table

Input	Value	Unit	Source
System size (DC nameplate)	300.44 (518 × 580 W)	kWp	LONGi Hi-MO 7 module family
Module family / model	LONGi Hi-MO 7 (HPBC 2.0 back-contact; LR7-72HGD)	—	LONGi Hi-MO 7 product page (610 W, up to 24.8% efficiency)
Inverter family / model	Sungrow SG125HT (×2, 250 kW AC total)	—	Sungrow string inverter range (incl. SG125HT C&I 3-phase)
Mounting system	Schletter Fix Z-Prof (AS/NZS 5033:2021 compliant clamp; install manual Rev. 04-2023)	—	Schletter Group fixed-tilt systems category — exact manual revision confirmed at RFQ
Module datasheet warranty (linear)	12-yr product / 30-yr linear power; bifaciality up to 80%	—	LONGi Hi-MO 7 datasheet
Performance ratio (PR)	0.85	—	CEC Products Program (PR band 0.80–0.90 typical for AU commercial rooftop) — bounded assumption
Specific yield, AU airport site	1,580	kWh/kWp/yr	Bounded model assumption — replace with site Solcast TMY before financial close
CapEx (turnkey rooftop)	1,250	AUD/kWp	CEC commercial rooftop cost guidance 2024 — bounded assumption within ±10%
Fixed OpEx (O&M + insurance)	1.5	% of CapEx/yr	Bounded model assumption
Inverter replacement (year 12)	120	AUD/kWp	Sungrow SG-HT service manual (capacitor-replace interval) + bounded assumption
Blended commercial tariff (Ausgrid EA029)	0.28	AUD/kWh	Ausgrid business & commercial tariffs (EA029 BLNT2AU, incl. GST)
Tariff escalation	3.0	%/yr	Bounded assumption — RBA target-band midpoint
Module degradation	0.5	%/yr	Bounded assumption consistent with LONGi linear-power warranty
Discount rate (WACC, nominal)	7.0	%/yr	Bounded assumption within AER nominal WACC band
Analysis horizon	25	years	Bounded assumption consistent with PV module linear-warranty term
Self-consumption share (model default)	85	% of generation	Bounded model assumption (GSE chargers operate daytime — to be confirmed by site load profile)
Export tariff (model default)	0.05	AUD/kWh	Bounded model assumption — small-export FiT band NSW 2024
Residual value (model default)	0.00	AUD	Bounded model assumption (conservative, set to zero at year 25)
Residual value year (model default)	25	year	Bounded model assumption (end-of-horizon)

2. TCO Summary (verbatim from scenario model)

TCO summary
Metric	Value
Currency	AUD
Horizon (years)	25
Discount rate	7.00 %
Total undiscounted cost (AUD)	591,170.44
Total discounted cost / PV of costs (AUD)	469,477.90
Total undiscounted benefit (AUD)	3,972,941.68
Total discounted benefit (AUD)	1,702,662.73
NPV (AUD)	1,233,184.83
IRR	0.3193
Simple payback (year)	3.28
Discounted payback (year)	3.84
LCOE (AUD/kWh)	0.0886

3. Computed Cash-Flow Table (verbatim from scenario model)

Year-by-year cash flow
Year	Cost (AUD)	Benefit (AUD)	Net (AUD)	Discount factor	Discounted net (AUD)	Energy (kWh)
0	375,000.00	0.0000	-375,000.00	1.00	-375,000.00	0.0000
1	5,625.00	116,537.67	110,912.67	0.9346	103,656.70	474,695.20
2	5,737.50	119,433.63	113,696.13	0.8734	99,306.61	472,321.72
3	5,852.25	122,401.56	116,549.31	0.8163	95,138.95	469,960.12
4	5,969.30	125,443.24	119,473.94	0.7629	91,146.10	467,610.31
5	6,088.68	128,560.50	122,471.82	0.7130	87,320.72	465,272.26
6	6,210.45	131,755.23	125,544.78	0.6663	83,655.78	462,945.90
7	6,334.66	135,029.35	128,694.68	0.6227	80,144.58	460,631.17
8	6,461.36	138,384.83	131,923.47	0.5820	76,780.66	458,328.02
9	6,590.58	141,823.69	135,233.11	0.5439	73,557.85	456,036.38
10	6,722.40	145,348.01	138,625.61	0.5083	70,470.23	453,756.19
11	6,856.84	148,959.91	142,103.06	0.4751	67,512.14	451,487.41
12	42,993.98	152,661.56	109,667.58	0.4440	48,693.72	449,229.98
13	7,133.86	156,455.20	149,321.34	0.4150	61,963.05	446,983.83
14	7,276.54	160,343.11	153,066.57	0.3878	59,361.86	444,748.91
15	7,422.07	164,327.64	156,905.57	0.3624	56,869.80	442,525.16
16	7,570.51	168,411.18	160,840.67	0.3387	54,482.30	440,312.54
17	7,721.92	172,596.20	164,874.28	0.3166	52,194.97	438,110.97
18	7,876.36	176,885.21	169,008.86	0.2959	50,003.62	435,920.42
19	8,033.89	181,280.81	173,246.93	0.2765	47,904.22	433,740.82
20	8,194.56	185,785.64	177,591.08	0.2584	45,892.91	431,572.11
21	8,358.45	190,402.41	182,043.96	0.2415	43,966.00	429,414.25
22	8,525.62	195,133.91	186,608.29	0.2257	42,119.95	427,267.18
23	8,696.14	199,982.99	191,286.85	0.2109	40,351.37	425,130.85
24	8,870.06	204,952.57	196,082.51	0.1971	38,657.00	423,005.19
25	9,047.46	210,045.64	200,998.18	0.1842	37,033.75	420,890.17

4. Scenario Verdict

Baseline (e = 3.0%, WACC = 7.0%): NPV AUD 1,233,185; simple payback 3.28 yr; discounted payback 3.84 yr; LCOE 0.0886 AUD/kWh. Strongly positive business case across all 25 yr; payback within the inverter-replacement cycle leaves a clear safety margin.
Site-specific specific yield (1,580 kWh/kWp/yr), self-consumption share (85%), and inverter-replacement cost (AUD 120/kWp in year 12) are bounded model assumptions and must be re-confirmed by a site-specific yield simulation (Solcast TMY / PVsyst) and a fixed-price O&M contract before financial close.

5. Cert & Compliance Block

Module qualification: IEC 61215-1:2021 ed2 (Terrestrial PV modules — Design qualification and type approval — Part 1: Test requirements) and IEC 61730-1/-2 (PV module safety) per the IEC 61215-1:2021 ed2 webstore listing.
Power-converter safety: IEC 62109-1:2010 (Safety of power converters for PV — General requirements) per the IEC 62109-1:2010 webstore listing.
UL PV-module safety (US-bound shipments): UL 61730-1 per the UL 61730-1 product page.
Installation: AS/NZS 5033:2021 (PV array installation). Install per the Schletter Fix Z-Prof manual; clamp torque values per Section 4.2 (manual revision confirmed at RFQ).
Inverter connection: AS/NZS 4777.2:2020. Verify that the Sungrow SG125HT is on the CEC approved inverters list at commissioning.
STC eligibility: both module and inverter must appear on the CEC Products Program approved lists current at commissioning.
Battery / transport of lithium: UN Manual of Tests and Criteria, Section 38.3 (UN 38.3), per the UN Manual of Tests and Criteria canonical page — applicable to GSE battery chargers, not to the PV array itself.

6. HS Code & Tariff Block (lookup instructions)

Component	HS subheading	Tariff lookup tool	Duty rate (AU MFN)
Crystalline-Si PV modules	8541.43	ABF current tariff lookup	0% (free, MFN) — confirm subheading & any FTA preference
String inverters (> 1 kW)	8504.40	ABF current tariff lookup	0% (free, MFN)
PV-rated DC cable	8544.60	ABF current tariff lookup	0% (free, MFN)
Aluminium mounting structure	7610.90	ABF current tariff lookup	5% (verify FTA preference)
Steel mounting structure	7308.20	ABF current tariff lookup	5% (verify FTA preference)
DC combiners / isolators	8536.90	ABF current tariff lookup	0% (free, MFN)

Lookup instructions: confirm the exact subheading and any FTA preferential rate (e.g. KAFTA, AANZFTA, CPTPP, RCEP, ChAFTA) on the ABF tariff-lookup tool before quoting a landed cost. PV modules under HS 8541.43 are free of MFN duty in Australia; aluminium mounting under 7610.90 attracts 5% MFN unless an FTA preference applies. For non-AU destinations use the corresponding national lookup tool: USITC HTS (US), UK Global Tariff, EU TARIC, Japan Customs, NZ Customs Working Tariff, SARS (ZA), GRA (GH), URA (UG).

Disclaimer: TradVolt does not provide legal or customs advice. HS classifications and duty rates are the importer's responsibility and must be confirmed with a licensed customs broker or the Australian Border Force. Numbers in this article are engineering estimates for an indicative TCO and are not a financial recommendation.

7. Calls to Action

Request a formal RFQ via the TradVolt RFQ form. Use-case tag can be added as a query string: https://tradvolt.com/rfq/?use_case=airport-gse-solar-300kwp-au.