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A structured side-by-side comparison of the FY2025 climate-related disclosures prepared by Contact Energy (CEN), Genesis Energy (GNE), Mercury NZ (MCY) and Meridian Energy (MEL). Covers consolidation approach, organisational boundary, GHG accounting standard cited, base year, emission-factor source, Scope 3 category coverage, intensity denominator, scenario analysis, transition plan disclosure, assurance provider and scope, and restatements. Every data point is cited to a page of the original source document.
A reader comparing “total emissions” across NZ’s four listed gentailers is comparing four different things — not because the companies disagree, but because NZ CS permits it.
Contact, Genesis, Mercury and Meridian all report under the Aotearoa New Zealand Climate Standards (NZ CS 1–3). But the framework each company cites as its primary GHG accounting basis differs. So does the base year. So does the set of Scope 3 categories estimated. So does the level and scope of independent assurance.
The result is a sector-level methodology-basis gap that makes a straight “total emissions” comparison meaningless unless the reader corrects for it. This page lists every material methodology choice each company made, and cites the page of the source document where each choice appears. The companion GHG Assurance Audit 2026 narrows the lens to the assurance dimension specifically.
Four peer companies, three different primary standards named in the basis of preparation.
“Scope 3 emissions” means a different boundary depending on which company you read.
Two of four peers have moved Scope 1 & 2 to reasonable assurance ahead of NZ SAE 1 phase-in.
Each company publishes a “total emissions” figure in its FY2025 climate statement. What goes intothat total differs company by company. The share of Meridian’s reported total that comes from Scope 3 is 99%. The share of Contact’s total from Scope 3 is 0%. A reader comparing totals across the four is implicitly weighting Scope 3 differently for each.
| Issuer | Reported total | Scope 1 + 2 | Scope 3 | S3 share | Source |
|---|---|---|---|---|---|
| GNE | 3.59M Scope 1 + Scope 2 (location-based) + Scope 3 | 2.54M | 1.05M | 29% | pp.47–48 |
| CEN | 742k Scope 1 + Scope 2 combined; Scope 3 not estimated | 742k | — | 0% (not estimated) | p.33–35 |
| MCY | 425k Scope 1 + Scope 2 (location-based) + Scope 3 | 219k | 205k | 48% | p.17 |
| MEL | 51k Scope 1 + Scope 2 (combined 715 tCO2e) + Scope 3 | 715 | 50k | 99% | pp.31–32 |
Absolute tonnes CO2-e, extracted directly from each issuer’s FY2025 climate statement / GHG inventory. Contact and Meridian report Scope 1 and Scope 2 as a combined figure; Genesis and Mercury report them separately (location-based Scope 2 used above).
Composition of each issuer’s reported “total emissions”
How to read this.The rank order of the four is preserved under any of these views — Genesis is largest, Meridian smallest. What the figures show is that “total emissions” is not a single comparable metric across the sector. For a like-for-like risk comparison, use Scope 1 + Scope 2 only (as reported or as location-based) and treat Scope 3 category-by-category, not in aggregate.
Each bar shows how many of the 15 GHG Protocol Scope 3 categories the issuer reports quantitatively in its FY2025 climate statement. The gap between the shortest and longest bar is the comparability problem in one picture.
“Total emissions” published by GNE (9 categories) and by CEN (0 categories) are not measuring the same thing. Neither approach is wrong under NZ CS as written. That is the underlying policy choice.
Each row is a methodological choice a climate statement preparer must make. Every data point cites the page of the source PDF where the value is stated; direct quotes are shown in italics.
| Field | CEN CEN Contact Energy Limited 1 July 2024 – 30 June 2025 · 138 pages | MEL MEL Meridian Energy Limited 1 July 2024 – 30 June 2025 (Year 7 of climate reporting) · 54 pages | GNE GNE Genesis Energy Limited 1 July 2024 – 30 June 2025 · 79 pages | MCY MCY Mercury NZ Limited 1 July 2024 – 30 June 2025 · 30 pages |
|---|---|---|---|---|
Consolidation approach | Operational controlp.47+ Consistent with NZ CS operational control principle. | Operational consolidation approachp.36 “Meridian’s emissions are calculated using the operational consolidation approach.” | Operational controlp.4 “Genesis does not have operational control of these entities (joint ventures, joint operations and associates are excluded from scope 1 and 2 emissions).” | Operational controlp.26 “The approach used to consolidate GHG emissions (operational control) on page 7 of the GHG Emissions Inventory report.” |
Organisational boundary | Contact Energy Limited and consolidated group Consolidated financial statements basis. | Meridian Energy Limited and group entitiesp.33 Operational consolidation — owned and operated facilities. | Genesis and subsidiaries; controlled entities; interests in associates and joint arrangementsp.4 JVs, joint operations and associates excluded from Scope 1 and 2 on operational-control basis. | Mercury NZ Limited and subsidiaries (the Group) — 19 power stations (hydro, geothermal, wind), retail electricity, gas, broadband and mobilep.4 Operational-control consolidation; all generation assets 100% renewable. |
GHG standard cited | GRI Standards and Integrated Reporting <IR> Frameworkp.2 GRI and <IR> explicitly cited; GHG Protocol not named as the primary standard. | ISO 14064-1:2018 — Greenhouse gases — Part 1p.33 “Meridian’s GHG Inventory is stated in accordance with the requirements of: ISO 14064-1:2018.” | GHG Protocol Corporate Standardp.61 “The GHG inventory has been prepared in accordance with the requirements of the GHG Protocol, which is an internationally recognised framework for carbon reporting.” | GHG Protocol Corporate Standard (revised edition) + Corporate Value Chain (Scope 3) Standardp.17 “We produce an annual Greenhouse Gas Emissions Inventory Report in accordance with The Greenhouse Gas Protocol: A Corporate Accounting and Reporting Standard (revised edition) and the Corporate Value Chain (Scope 3) Accounting and Reporting Standard.” |
Base year (and reason) | FY2022 Target-setting base year. | FY2021p.35 Base year for SBTi-verified “Half by 30” absolute-reduction targets. | FY2020 (1 July 2019 – 30 June 2020)p.63 Aligned with SBTi target base year. | FY2022 (year ended 30 June 2022)p.11 Base year for SBTi-aligned reduction targets; FY25 emissions intensity 0.023 kg CO2e/kWh (8.9% below base). |
Emission-factor source | MfE 2024 factors (Ministry for the Environment) | Not specified in extracted section; ISO 14064-compliant factors (typically MfE / IEA)p.33 | Ministry for the Environment (MfE) 2024 factorsp.63 “We have used emission factors published by the Ministry for the Environment (MfE) for calculation.” | Multiple — GHG Protocol default factors, MfE, plus internally calculated Unique Emission Factors for geothermalp.26 Geothermal UEFs from plant-specific steam testing; externally assured when prior-year deviation > 5%. |
Intensity denominator | Absolute emissions reported; no standard intensity denominator disclosed | t CO2e per unit output (generation)p.34 | t CO2e per GWh generatedp.47 | kg CO2e per kWh of generationp.17 FY25 intensity: 0.023 kg CO2e/kWh. Does not adjust for part-ownership of geothermal assets or NZ ETS credits. |
Scope 3 coverage | 0 of 15 GHG Protocol categories Scope 3 not estimated in FY25 disclosure. | 7 of 15 GHG Protocol categoriesp.33 Disclosed: 1, 3, 6, 7, 8, 9, 11 Covers purchased goods & services, fuel & energy, business travel, employee commuting, upstream & downstream leased assets, use of sold products. | 9 of 9 GHG Protocol categoriesp.62 Disclosed: 1, 2, 3, 4, 5, 8, 9, 11, 15 Categories explicitly mapped in the Scope 3 inventory table on pages 61–62. | 6 of 15 GHG Protocol categoriesp.3 Disclosed: 1, 2, 8, 9, 11, 15 FY25 expanded Scope 3 to include Category 2 (Capital Goods, ~66% of S3) and Category 15 (Investments), driving the restatement below. |
Scenario analysis | Not disclosed in FY25 No scenario analysis disclosed in FY25; asset-centric qualitative roadmap instead. | 3 scenarios · quantitativep.14–22 Net Zero Revolution (1.5°C) · Adaptive Evolution · Hot House Horizons: Now – 2050 | 4 scenarios · quantitativep.19–22 Coordinated transformation (1.5°C) · Green tape (policy-driven) · Delayed transformation (3°C+) · Hot house (current policies) Horizons: Short 2030, Medium 2040, Long 2050 | 4 scenarios · quantitativep.12 Teal (1.5°C) · Purple (2.5°C) · Amber (3°C) · Maroon (3°C+) Horizons: Current <1yr, Short 1–3yr, Medium 3–10yr, Long 10–30yr |
Transition plan | Net-zero 2035 strategic roadmap (Manawa hydro acquisition, TCC lifecycle management)p.34 Directional roadmap disclosed; not presented as a costed plan. | SBTi-verified “Half by 30” targets — absolute 50% Scope 1 & 2 reduction by FY30 from FY21 basep.35 | Gen35 strategy — costed strategic framework with climate-specific targetsp.6 | Strategy across five pillars — Kaitiakitanga, Kiritaki, Ngā Tāngata, Kōtuitanga, Arumoni. FY25 growth CAPEX $347m (100% renewable). SBTi target validation pending.p.4 Costed project examples disclosed ($90m Karāpiro refurb, $4.5m NCG reinjection); full transition-plan cost quantification not published. |
Restatements | None disclosed | Yesp.34 FY25 acquisition of a 138-hectare Waikato dairy farm (2,376 tCO2e) triggered a Scope 3 base-year revision. Material acquisition changed the Scope 3 boundary sufficiently to require base-year adjustment. | None disclosed | Yesp.11 FY22–FY24 Scope 3 restated to include Category 1 (purchased goods & services) and Category 2 (capital goods). FY24 Scope 3 increased by 38,262 tCO2e (~28%) post-restatement; Capital Goods alone now 66,192 tCO2e. Completed full Scope 3 materiality assessment in FY25 under NZ CS; broader boundary adopted. |
Assurance provider | Ernst & Young (EY)p.124 ISAE 3410 / NZ SAE 1 | KPMGp.52 ISAE 3410 / NZ SAE 1 | Deloitte Limited (on behalf of Auditor-General)p.70 ISAE 3410 / NZ SA 1 | Auditor-General (Ernst & Young appointed; Matthew Cowie)p.26 NZ SAE 1 / ISAE (NZ) 3000 (Revised) / ISAE (NZ) 3410 |
Assurance level & scope | Limited assurance Scope: GRI disclosures (selected E/S/G metrics) Qualifications: None noted. | Reasonable (Scope 1 & 2); Limited (Scope 3) Scope: Scope 1, 2 and 3 GHG emissions Qualifications: None noted. | Reasonable (Scope 1 & 2); Limited (Scope 3) Scope: Scope 1, 2 and 3 GHG emissions Qualifications: Unqualified on both reasonable (Scope 1 & 2) and limited (Scope 3) opinions. | Limited (across Scope 1, 2 and 3) Scope: Scope 1, Scope 2 (location-based), Scope 3 gross emissions; GHG Protocol compliance statement; boundary & consolidation; emission factors & GWP sources; exclusions; restatements Qualifications: Two key matters disclosed: (i) Scope 3 spend-based methods for purchased goods & capital goods (~19% of total emissions) carry inherent uncertainty; (ii) Scope 1 geothermal UEFs reliant on steam-flow measurement. Restated comparative Scope 3 (FY22–FY24) is not within the FY25 assurance scope. |
The GHG Protocol defines 15 Scope 3 categories. “Disclosed” means a quantitative figure is stated. “Not estimated” means the company explicitly stated the category is not estimated for the reporting year. “Not disclosed” means no quantitative figure could be identified in the source document.
| GHG Protocol category | CEN | MEL | GNE | MCY |
|---|---|---|---|---|
| 1. Purchased goods & services | Not estimated | Disclosed | Disclosed | Disclosed |
| 2. Capital goods | Not estimated | — | Disclosed | Disclosed |
| 3. Fuel- & energy-related | Not estimated | Disclosed | Disclosed | — |
| 4. Upstream transport | Not estimated | — | Disclosed | — |
| 5. Waste | Not estimated | — | Disclosed | — |
| 6. Business travel | Not estimated | Disclosed | — | — |
| 7. Employee commuting | Not estimated | Disclosed | — | — |
| 8. Upstream leased assets | Not estimated | Disclosed | Disclosed | Disclosed |
| 9. Downstream transport | Not estimated | Disclosed | Disclosed | Disclosed |
| 10. Processing of sold products | Not estimated | — | — | — |
| 11. Use of sold products | Not estimated | Disclosed | Disclosed | Disclosed |
| 12. End-of-life | Not estimated | — | — | — |
| 13. Downstream leased assets | Not estimated | — | — | — |
| 14. Franchises | Not estimated | — | — | — |
| 15. Investments | Not estimated | — | Disclosed | Disclosed |
The Aotearoa New Zealand Climate Standards require entities to apply the operational-control approach to their organisational boundary, and to explain deviations. All four issuers converge on operational control — but the framework they cite as their primary GHG accounting basis differs, and that matters because each framework defines category boundaries, reporting thresholds and disclosure expectations slightly differently.
The most material comparability gap sits in Scope 3. Genesis reports 9 of 15 categories, Meridian 7, Mercury 6, and Contact does not estimate Scope 3 for FY25. A reader comparing “total emissions” across the four companies is therefore comparing four different things — not because the companies are dishonest, but because the standard permits meaningful preparer discretion on scope boundaries.
Base-year choice compounds this. Genesis uses FY2020, Meridian FY2021, and Contact and Mercury both use FY2022. Target progress reported against different base years is not directly comparable, even when both targets are expressed in the same percentage-reduction form. Mercury’s FY25 restatement of three prior years of Scope 3 — adding capital goods at 66,192 tCO2e — is a live illustration of how Scope 3 boundaries move year to year even at one company.
Assurance scope is the third axis. Two of four issuers (Genesis and Meridian) have moved Scope 1 and 2 to reasonable assurance. Mercury remains on limited assurance across all three scopes; Contact remains on limited assurance across a broader GRI perimeter. Under NZ SAE 1 as it phases in, the level and scope of assurance will become a first-class comparability dimension in its own right.
Each data point in this page is extracted directly from the company’s FY2025 climate-related disclosures or integrated report. Page numbers refer to PDF page numbers of the source document. Direct quotes are preserved verbatim in italics; where a figure is stated but the exact page could not be isolated, the cell is left blank rather than populated with a guess.
Extraction date: 2026-04-20.
NZ CS as currently written permits the methodology discretion catalogued on this page. Three amendments would materially close the comparability gap without imposing new calculation burden:
Data sourced from publicly available records. Our datasets may not be complete. Automated analysis can produce errors. If you believe any data on this page is incorrect, please contact us at hello@nzxplorer.co.nz. For informational purposes only. Not investment advice.