Several factors have influenced updates to emissions factors this year, including advancements in scientific research, shifts in energy production, and improvements in data accuracy.
The main changes since the last publication of the Measuring Emissions Guide are:
Purchased energy emission factor
The annual electricity factor for 2024 is substantially higher than the 2023 factor published in last year’s guide, which can be attributed to shifting electricity generation dynamics. In 2022 and 2023, emissions from electricity generation were relatively low due to favourable weather conditions and strong hydro inflows. In contrast, 2024 saw an increase in the proportion of fossil-based generation. This rise also impacts associated emissions factors, including Travel and Freight (for electric and PHEV vehicles), and Working from Home emissions factors.
Business travel – Hotel stay emission factors
Hotel Stay emission factors have been updated based on the latest information from the Cornell Hotel Sustainability Benchmarking Index. This has led to significant adjustments in emission factors for most countries, driven by hotel reclassification within the data source, methodological changes, and updates to the composition of hotels providing data.
Refrigerant & other gases
Propane (R-290) and their associated blends i.e. 436A and 436B specific gases have been updated from The Intergovernmental Panel on Climate Change (IPCC) AR4 to IPCC AR5 to improve accuracy in emissions reporting.
Emissions calculation methodology changes
Changes in the emissions calculation methodology, as outlined in New Zealand’s Greenhouse Gas Inventory 1990 – 2023 have resulted in updates in emissions factors across the following domains:
- Waste: The 2024 waste emission factors includes the new Waste Model which incorporates more comprehensive and up to date data, enhancing the accuracy of emissions estimates for the waste sector.
- LULUCF (Land Use, Land-Use Change, and Forestry): The 2024 LULUCF emission factors have been adjusted to reflect the revised expected harvest age of hardwoods, impacting carbon stock calculations.
- Agriculture: The 2024 agricultural emission factors include refinements in livestock emissions calculations, adjustments to poultry population accounting, and methodological improvements based on updated agricultural activity data.