Import Sungrow SG350HX On-Grid String Inverter from China to New Zealand — Stadium Rooftop TCO
Headline TCO verdict (illustrative, computed): NPV ≈ USD 698,268; simple payback ≈ 5.41 yr; discounted payback ≈ 6.97 yr; LCOE ≈ USD 0.1457/kWh; IRR ≈ 18.57% on a 20-year horizon at a 7.00% discount rate with stated inputs. Illustrative payback band ~4.0–7.2 yr across a CapEx band of 450,000–800,000 NZD-equivalent on the same operating envelope. All figures ILLUSTRATIVE — NOT A QUOTE; firm pricing via RFQ. Equipment: Sungrow SG350HX, 350 kW on-grid string inverter, manufactured by Sungrow Power Supply Co., Ltd. (Hefei, CN). Location: New Zealand (commercial rooftop, stadium). Horizon: 20 yr. Discount rate: 7.00%/yr. Evidence date: 2026-09-22. Limitation: no PVSyst site-specific yield, no firm EPC quote, no confirmed NZ Customs Working Tariff ruling for HS 8504.40 — all marked PENDING.
| Item | Value |
|---|---|
| Equipment / OEM | Sungrow SG350HX — Sungrow Power Supply Co., Ltd. |
| Site / country | Stadium rooftop, New Zealand |
| DC system size | 350 kWp (DC/AC ≈ 1.0) |
| Horizon / discount rate | 20 yr / 7.00% |
| Total undiscounted cost | USD 625,000.00 (Day-0 CapEx, model assumption) |
| Total undiscounted benefit (20 yr) | USD 2,580,833.88 |
| PV of benefits | USD 1,323,268.15 |
| NPV | USD 698,268.15 |
| IRR | 18.57% |
| Simple payback | 5.41 yr |
| Discounted payback | 6.97 yr |
| LCOE | USD 0.1457/kWh |
| Illustrative payback band | ~4.0–7.2 yr (CapEx 450k–800k NZD-equivalent on same envelope) |
| Verdict | Positive NPV on stated inputs; site-specific yield, tariff and finance terms to be confirmed via RFQ. |
OEM datasheet reference: Sungrow SG350HX product family datasheet, published by Sungrow Power Supply Co., Ltd. — see Sungrow product portal for current revision (datasheet PDF returned by the manufacturer behind a JS-rendered product page; revision, cert numbers and torque/SOC limits confirmed at RFQ).
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1. System definition (inputs)
| Parameter | Value | Unit | Source / Note |
|---|---|---|---|
| DC system size | 350 | kWp | Use-case definition, stadium rooftop |
| Inverter AC output (per unit) | 350 | kW | Sungrow SG350HX product family datasheet — OEM portal sungrowpower.com/en; specific datasheet PDF revision confirmed at RFQ |
| Inverter topology | On-grid, transformerless string inverter | — | Sungrow SG350HX datasheet, OEM portal sungrowpower.com/en |
| Grid interface standard | AS/NZS 4777.2:2020 (inverter requirements); AS/NZS 4777.1:2016 (installation) | — | Claim: AS/NZS 4777.2:2020 is the standard for inverter-connected generation in NZ. Src: Standards New Zealand — AS/NZS 4777.2:2020 record. URL: standards.govt.nz — AS/NZS 4777.2:2020. accessed: 2026-09-22. |
| Product safety standard | IEC 62109-1 / IEC 62109-2 | — | Claim: IEC 62109 is the base safety standard for PV power converters. Src: IEC Webstore — IEC 62109-1 publication page. URL: webstore.iec.ch — IEC 62109-1. accessed: 2026-09-22. |
| Performance / utility interface | IEC 61683, IEC 61727 | — | Claim: IEC 61683 and IEC 61727 define measurement procedures and utility-interface characteristics for PV inverters. Src: IEC Webstore. URL: webstore.iec.ch — IEC 61683 and webstore.iec.ch — IEC 61727. accessed: 2026-09-22. |
| Annual energy yield reference | 1 200 | kWh/kWp/yr | Indicative NZ-specific yield range; site-specific PVSyst result overrides. Src: PENDING — model assumption |
| Self-consumption assumption | 90 | % | Stadium daytime-match load profile (day-loaded venue) — model assumption |
| Electricity price assumption | 0.28 | NZD/kWh | ILLUSTRATIVE — NZ commercial tariff, retailer-dependent. Src: PENDING — model assumption |
| PV module (companion) reference family | LONGi Hi-MO 5 / Hi-MO 6 (550 Wp class) or Jinko Tiger Neo (550 Wp class) | — | OEM portals: longi.com/en, jinkosolar.com/en; specific SKU and datasheet revision confirmed at RFQ |
| Discount rate (WACC) | 7.00 | % / yr | Modeller input |
| Analysis horizon | 20 | yr | Modeller input |
2. CapEx — Indicative landed cost (per site, 350 kW)
All values ILLUSTRATIVE — NOT A QUOTE. Duty and GST rates marked PENDING — lookup. The CapEx line items below are model assumptions; only the Day-0 total of USD 625,000 is used by the COMPUTED tables.
| Line item | Qty | Unit | Unit value (USD) | Subtotal (USD) | Source / Note |
|---|---|---|---|---|---|
| Sungrow SG350HX, on-grid string inverter, 350 kW class | 1 | unit | PENDING — lookup | Included in Day-0 total | OEM unit price varies by region, warranty pack and configuration. Confirm via RFQ. Datasheet portal: sungrowpower.com/en |
| PV modules (LONGi Hi-MO 6 or Jinko Tiger Neo, 550 Wp class) | 636 | pcs | PENDING — lookup | Included in Day-0 total | Indicative DC/AC ratio ~1.0. OEM portals: longi.com/en, jinkosolar.com/en |
| Mounting structure, rooftop ballasted / fixed | 1 | lot | PENDING — lookup | Included in Day-0 total | Rooftop-specific (wind load per AS/NZS 1170.2) |
| DC cabling, AC cabling, combiner boxes | 1 | lot | PENDING — lookup | Included in Day-0 total | BoS passive |
| MV transformer + switchgear (if required by lines co.) | 1 | lot | PENDING — lookup | Included in Day-0 total | Function of point-of-connection voltage |
| Freight, sea, CN → NZ (LCL/FCL) | 1 | lot | PENDING — lookup | Included in Day-0 total | Origin port (e.g. Shanghai/Ningbo) → Tauranga / Auckland / Lyttelton |
| Marine insurance | — | — | ~0.3% of CIF | Included in Day-0 total | Industry typical; confirm with broker |
| Customs broker / clearance fees (NZ) | — | — | PENDING — lookup | Included in Day-0 total | Per NZ Customs Service guidance for the entry type |
| Installation & commissioning labour (NZ) | — | — | PENDING — lookup | Included in Day-0 total | Local EPC scope |
| Day-0 CapEx (total, model assumption) | — | — | — | USD 625,000.00 | Single Year-0 outflow used by the COMPUTED tables |
2.1 Duty / GST stack — NZ import (lookup pending)
| HS national line | Program | As-of | SoT |
|---|---|---|---|
| 8504.40 (candidate — Static converters; static inverters) | Working Tariff Document (NZ Customs Service) — MFN duty | 2026-09-22 | PENDING — exact 10-digit line, applicable rate and any concession to be confirmed on the NZ Working Tariff Document at the time of shipment. Src: NZ Customs Service Working Tariff Document — Section 85, Chapter 8504.40. URL: customs.govt.nz — Working Tariff Document. accessed: 2026-09-22. |
| 8504.40 (candidate) | GST on imported goods (15.0% standard rate, basis = VFD) | 2026-09-22 | PENDING — confirm on the IRD GST schedule at the time of entry. Src: NZ Inland Revenue — Goods and Services Tax (GST). URL: ird.govt.nz — GST. accessed: 2026-09-22. |
| 8504.40 (candidate) | China–NZ FTA (FORM N) preferential duty, if origin and certificate meet rules | 2026-09-22 | PENDING — confirm on the China–NZ FTA rules of origin chapter at the time of entry. Src: MFAT — China–NZ FTA rules of origin chapter (Chapter 3). URL: mfat.govt.nz — China–NZ FTA. accessed: 2026-09-22. |
All duty / GST rates on this page are PENDING — lookup. The COMPUTED TCO tables do not load any duty or GST figure: the only Cost line in the cash flow is the Year-0 Day-0 outflow of USD 625,000.00 (model assumption).
3. OpEx — Indicative annual operating cost (model assumption)
The COMPUTED tables do not load any annual OpEx line: every annual row in the cash-flow table carries Cost = 0.0000. The OpEx line items below are model assumptions documenting the boundary of the model and the line items that would be quantified in a firm quote.
| Line item | Annual (USD/yr) | Source / Note |
|---|---|---|
| Sungrow OEM service / extended warranty | 0.00 (not loaded) | Optional 5→10 yr extension pack, region-dependent. Confirm via Sungrow warranty letter. |
| Preventive maintenance (annual site visit, thermography, sample-string IV curve) | 0.00 (not loaded) | Local EPC scope |
| Module cleaning (rooftop, rainfall-dependent) | 0.00 (not loaded) | Stadium roof — access and water-use rules apply |
| Monitoring SaaS / SCADA communications | 0.00 (not loaded) | Sungrow iSolarCloud or third-party |
| Insurance (all-risk, property) | 0.00 (not loaded) | Typically ~0.1–0.3% of replacement value / yr |
| Inverter replacement reserve (sinking fund) | 0.00 (not loaded) | Reserve annualised over inverter service life |
4. Computed TCO tables (computed)
The tables below are the only arithmetic on the page. Prose in this section is limited to restating inputs and the verbatim figures; no worked derivations, no closed-form checks, no other financial figures.
4.1 Inputs used by the COMPUTED model
- Horizon: 20 yr.
- Discount rate: 7.00% per annum.
- CapEx (Year 0, single outflow): USD 625,000.00 (model assumption; matches the indicative 350 kW stadium-rooftop scope).
- Annual OpEx: 0.00 USD/yr (model assumption; not loaded).
- Residual value: 0.00 USD (model assumption; not loaded).
- Replacement capex items (capex[1..8], replacements[0]): DROPPED-ITEM (model assumption; not loaded).
- PV annual energy (Year 1): 420,000 kWh, degrading by 0.5%/yr thereafter (model assumption).
- Tariff escalation: 1.5%/yr (model assumption; produces the benefit series in the table).
- Self-consumption and export weighting: folded into the benefit series already (model assumption).
4.2 TCO summary
| Metric | Value |
|---|---|
| Currency | USD |
| Horizon (years) | 20 |
| Discount rate | 7.00 % |
| Total undiscounted cost (USD) | 625,000.00 |
| Total discounted cost / PV of costs (USD) | 625,000.00 |
| Total undiscounted benefit (USD) | 2,580,833.88 |
| Total discounted benefit (USD) | 1,323,268.15 |
| NPV (USD) | 698,268.15 |
| IRR | 0.1857 |
| Simple payback (year) | 5.41 |
| Discounted payback (year) | 6.97 |
| LCOE (USD/kWh) | 0.1457 |
4.3 Year-by-year cash flow
| Year | Cost (USD) | Benefit (USD) | Net (USD) | Discount factor | Discounted net (USD) | Energy (kWh) |
|---|---|---|---|---|---|---|
| 0 | 625,000.00 | 0.0000 | -625,000.00 | 1.00 | -625,000.00 | 0.0000 |
| 1 | 0.0000 | 111,720.00 | 111,720.00 | 0.9346 | 104,411.21 | 420,000.00 |
| 2 | 0.0000 | 113,384.63 | 113,384.63 | 0.8734 | 99,034.53 | 417,900.00 |
| 3 | 0.0000 | 115,074.06 | 115,074.06 | 0.8163 | 93,934.71 | 415,810.50 |
| 4 | 0.0000 | 116,788.66 | 116,788.66 | 0.7629 | 89,097.51 | 413,731.45 |
| 5 | 0.0000 | 118,528.81 | 118,528.81 | 0.7130 | 84,509.41 | 411,662.79 |
| 6 | 0.0000 | 120,294.89 | 120,294.89 | 0.6663 | 80,157.57 | 409,604.48 |
| 7 | 0.0000 | 122,087.29 | 122,087.29 | 0.6227 | 76,029.83 | 407,556.45 |
| 8 | 0.0000 | 123,906.39 | 123,906.39 | 0.5820 | 72,114.65 | 405,518.67 |
| 9 | 0.0000 | 125,752.59 | 125,752.59 | 0.5439 | 68,401.08 | 403,491.08 |
| 10 | 0.0000 | 127,626.31 | 127,626.31 | 0.5083 | 64,878.74 | 401,473.62 |
| 11 | 0.0000 | 129,527.94 | 129,527.94 | 0.4751 | 61,537.79 | 399,466.25 |
| 12 | 0.0000 | 131,457.90 | 131,457.90 | 0.4440 | 58,368.88 | 397,468.92 |
| 13 | 0.0000 | 133,416.63 | 133,416.63 | 0.4150 | 55,363.16 | 395,481.58 |
| 14 | 0.0000 | 135,404.53 | 135,404.53 | 0.3878 | 52,512.21 | 393,504.17 |
| 15 | 0.0000 | 137,422.06 | 137,422.06 | 0.3624 | 49,808.08 | 391,536.65 |
| 16 | 0.0000 | 139,469.65 | 139,469.65 | 0.3387 | 47,243.20 | 389,578.97 |
| 17 | 0.0000 | 141,547.75 | 141,547.75 | 0.3166 | 44,810.39 | 387,631.07 |
| 18 | 0.0000 | 143,656.81 | 143,656.81 | 0.2959 | 42,502.87 | 385,692.92 |
| 19 | 0.0000 | 145,797.30 | 145,797.30 | 0.2765 | 40,314.17 | 383,764.45 |
| 20 | 0.0000 | 147,969.68 | 147,969.68 | 0.2584 | 38,238.18 | 381,845.63 |
4.4 Headline read-out
- NPV (USD): 698,268.15
- IRR: 18.57%
- Simple payback (yr): 5.41
- Discounted payback (yr): 6.97
- LCOE (USD/kWh): 0.1457
- Illustrative payback band across a CapEx band of 450,000–800,000 NZD-equivalent on the same operating envelope: ~4.0–7.2 yr (no NPV recomputed outside the COMPUTED tables).
5. Sensitivity (illustrative — qualitative only)
No quantitative sensitivity is recomputed outside the COMPUTED tables. The table below restates the directional effect on payback only.
| Variable | −20 % | Base | +20 % | Effect on payback |
|---|---|---|---|---|
| Specific yield (kWh/kWp/yr) | 960 | 1 200 | 1 440 | Payback scales inversely with yield. |
| CapEx (NZD-equivalent) | −20 % | Day-0 625,000 USD ≈ mid-band | +20 % | Payback scales linearly with CapEx. |
| Electricity price (NZD/kWh) | 0.224 | 0.28 | 0.336 | Payback scales inversely with tariff. |
| Self-consumption (%) | 72 | 90 | 100 | Higher self-consumption shortens payback. |
ILLUSTRATIVE — NOT A QUOTE. Run a site-specific PVSyst / SAM model and a fixed-price EPC proposal before committing capital.
6. Compliance, certification & grid connection
- Product safety: IEC 62109-1 and IEC 62109-2 (or AS/NZS 62109 equivalent). Confirm certificate number and issuer on the Sungrow SG350HX datasheet. Src: IEC Webstore — IEC 62109-1. URL: webstore.iec.ch — IEC 62109-1. accessed: 2026-09-22.
- Utility interface (NZ): AS/NZS 4777.2:2020 (inverter requirements) and AS/NZS 4777.1:2016 (installation). Src: Standards New Zealand. URL: standards.govt.nz — AS/NZS 4777.2:2020. accessed: 2026-09-22.
- Grid code / connection: Electricity Authority and the relevant lines company govern connection under the Electricity Industry Participation Code 2010, Part 6 (Connection of Distributed Generation) and Schedule 6.1 (Technical Code). Src: Electricity Authority Te Mana Hiko — Electricity Industry Participation Code 2010. URL: ea.govt.nz — Electricity Industry Participation Code 2010. accessed: 2026-09-22.
- EMC: Typically demonstrated against the IEC 61000 series and/or AS/NZS CISPR 11. Confirm cert number with Sungrow.
- Structural / wind: AS/NZS 1170.2 for rooftop wind loads (rooftop mounting design). Src: Standards New Zealand. URL: standards.govt.nz — AS/NZS 1170.2:2021. accessed: 2026-09-22.
- Disclaimer: Certificate numbers and issuing bodies are model-specific. Tradvolt does not assert any specific certification for the SG350HX without the OEM datasheet revision reference.
7. Duty / HS code block
| HS national line | Program | As-of | SoT |
|---|---|---|---|
| 8504.40 (Static converters; static inverters — candidate NZ working tariff line) | Most-Favoured-Nation (MFN) duty | 2026-09-22 | PENDING — confirm on the NZ Customs Service Working Tariff Document, Section 85, Chapter 8504.40 |
| 8504.40 | China–NZ FTA preferential duty (FORM N), if origin and ROO met | 2026-09-22 | PENDING — confirm against the China–NZ FTA rules of origin (Chapter 3) |
| 8504.40 | GST on imported goods (15.0 % standard rate, basis = VFD) | 2026-09-22 | PENDING — confirm on the IRD GST schedule at the time of entry |
Official portal: NZ Customs Service Working Tariff Document — URL: customs.govt.nz — Working Tariff Document. HS code to look up: 8504.40 (candidate). All duty / GST rates on this page are PENDING — lookup and must be reconfirmed at the time of entry.
8. Request a firm quote
Submit your project details — Tradvolt returns a binding quote against an OEM-confirmed SKU, freight lane and duty ruling.
FAQ
Q1. What HS code applies to a 350 kW on-grid solar inverter imported into New Zealand?
The candidate HS subheading commonly used for static converters (including solar inverters) is 8504.40. The exact 10-digit NZ Working Tariff line, applicable duty rate and GST treatment must be confirmed on the NZ Customs Service Working Tariff Document at the time of shipment. Tradvolt marks the rate as PENDING — lookup.
Q2. Does New Zealand require grid-connection certification for a 350 kW inverter?
Connection of generation equipment to a New Zealand distribution or transmission network is regulated by the Electricity Authority and the relevant lines company under the Electricity Industry Participation Code 2010, Part 6 (Connection of Distributed Generation) and Schedule 6.1 (Technical Code). The typical technical interface requirement for inverter-connected generation is AS/NZS 4777.2:2020 (with AS/NZS 4777.1:2016 for installation). Confirm the exact cert reference and issuer for the specific inverter SKU with the local lines company before procurement.
Q3. What is the indicative payback period for a 350 kW stadium rooftop installation on the Sungrow SG350HX?
On the illustrative inputs stated on this page (350 kWp DC, NZ-specific yield reference, electricity price assumption, fixed OpEx) the COMPUTED model returns simple payback ≈ 5.41 yr, discounted payback ≈ 6.97 yr, NPV ≈ USD 698,268, IRR ≈ 18.57% and LCOE ≈ USD 0.1457/kWh. Across an illustrative CapEx band of 450,000–800,000 NZD-equivalent on the same operating envelope, simple payback sits in the range ~4.0–7.2 yr. ILLUSTRATIVE — NOT A QUOTE; site-specific yield, shading, tariff and finance terms will move the result.
Q4. Is the pricing on this page a firm offer?
No. All unit pricing, freight, duty and OpEx figures on this page are labelled ILLUSTRATIVE — NOT A QUOTE. Use the RFQ form to receive a firm quotation within 48 hours.
Q5. What documents should accompany the shipment for NZ Customs clearance?
Typical set: commercial invoice, packing list, bill of lading or airway bill, certificate of origin (e.g. China–NZ FTA FORM N if applicable), product test certificates (e.g. IEC 62109-1/-2, IEC 61683, IEC 61727, AS/NZS 4777.2) and any lines-company pre-approval letter. Confirm with NZ Customs Service and your customs broker for the consignment.
Q6. What warranty is standard for the Sungrow SG350HX?
Sungrow's published standard warranty for the SG350HX utility-class string inverter is 5 years, with optional extension packs (typically to 10 years) sold separately by region. Confirm the exact term and labour/decommissioning coverage in the Sungrow warranty letter for the specific serial range before procurement.
All figures ILLUSTRATIVE — NOT A QUOTE. Duty, GST and certification outcomes are subject to confirmation against the official portals cited. Computed TCO tables are computed for the stated scenario; everything else is a model assumption. Last reviewed: 2026-09-22.