On 5 August 2026 the Government confirmed both halves of this year's ETS review: the unit limits and price control settings for 2027-2031, and the annual updates to the regulations. We covered the supply and price side in ETS settings confirmed to 2031. This article is about the other half, which gets far less attention but touches the number at the centre of every emitter's year: the emission factor.
An emission factor is the multiplier that converts a physical activity - a terajoule of gas burned, a kilolitre of fuel supplied, a tonne of waste to landfill - into tonnes of carbon dioxide equivalent, which is what you must surrender New Zealand Units against. The Ministry reviews these default factors periodically so they reflect the fuel and activity actually seen in New Zealand today. This year's review updated several of them, left one alone, and tightened the rules for landfills that calculate their own factor.
What was confirmed
The Government adopted the regulation proposals it consulted on, with one exception: the proposed change to the default emission factor for waste was not made. Everything takes effect on 1 January 2027, and the updated fuel factors apply to activity in the 2027 calendar year, reported in 2028.
| Regulation change | Decision, effective 1 January 2027 |
|---|---|
| Natural gas factors | Updated. The per-field default factors (tonnes CO2e per terajoule) were re-based on the most recent data. |
| Geothermal factors | Updated. Default factors move to a three-year rolling average of approved unique factors, which better reflects each field. |
| Liquid fossil fuel factors | Updated. Re-based to the quality of imported fuel now that all liquid fuel is imported. Changes are minor for most grades. |
| Waste factor | Unchanged. The default stays at 1.023 tonnes CO2e per tonne of waste - this was the one proposal not adopted. |
| Landfill unique factors | Tighter. The oxidation credit is removed and the evidence bar is raised for sites claiming very high gas capture, so their reported emissions become more accurate - and, in most cases, higher. |
| Contaminated land | Waste from remediating historic contaminated land is exempted, to remove a disincentive to clean-ups. |
What it means in practice
For most participants the factor changes are small, and the direction is towards accuracy rather than a deliberate tightening. Three groups will notice more than others.
Fuel suppliers and importers
The liquid fossil fuel factors have been re-based to reflect that every drop of liquid fuel is now imported. For a large obligation the change in the surrender number is real but modest, and it is a matter of using the correct 2027 factor for each fuel grade rather than any change in how the calculation works.
Gas and geothermal generators
Natural gas factors move with the latest field data, and geothermal moves to a rolling average that tracks each field more closely. If you already use an approved unique emissions factor, that continues; the default is simply a more current fallback.
Landfill operators and councils
This is where the change bites hardest, and it is worth planning for. The waste default itself is unchanged, but the way a landfill with a gas capture system calculates its own unique factor is tightened: the oxidation credit is removed and high-capture claims need stronger evidence. For a site with an efficient capture system, that generally means a higher reported figure - and therefore a larger annual NZU purchase - from the 2027 year onward. If you operate a disposal facility, this is a number worth re-running now rather than discovering at surrender time.
How Carbon Trader keeps pace
Our free My Obligations calculator does not approximate these factors - it uses the statutory defaults directly and cites the regulation behind each figure, so the number it gives you is the number the scheme expects. It already models waste disposal (including an approved unique emissions factor if you hold one), liquid fossil fuels with the correct deductions for international bunkers, opt-in sales and zero-rated exports, coal, natural gas field by field, and synthetic greenhouse gases. It is free and needs no account.
Because the tool is built on the published regulations rather than a fixed table, it is maintained against them: from the 2027 reporting year it reflects the confirmed factors above, with the waste default correctly held at 1.023. You can check your position against the current rules today, and against the 2027 rules as that year approaches, without waiting for a spreadsheet to circulate.
When the number turns into a decision - covering a shortfall, or planning a procurement for the year - the rest of the platform is built for it: fully identity-verified counterparties, escrowed settlement where money and units move together, a published fee schedule, and an auditable record of every step for your file. You can also look up what any ETS participant has reported, including your own organisation, in our free ETS participant data tool.
Contact us
Want to understand what the confirmed 2027 factors mean for your surrender obligation, or model a landfill position under the new unique-factor rules? Contact Carbon Trader® for platform guidance and operational support. Carbon Trader® does not provide financial, legal, tax or investment advice; for official ETS information, refer to the New Zealand Emissions Trading Scheme.