Stat Chat: Energy-Related Greenhouse Gas Emissions by Sector
We have increased the depth of field on our emissions estimates, and now other greenhouse gases step into focus, alongside carbon dioxide.
Emissions estimates – increased depth of field including CO2, CH4 and N2O as CO2eq
SEAI’s Energy Statistics team have just published the 2025 edition of their flagship annual Energy in Ireland report – a summary of Ireland’s definitive national energy statistics data, up to 2024. The data visualization panel below shows the final energy consumption by sector in 2024 – Ireland's energy demand. By hovering over a bubble category, you will see an interactive tooltip that shows a breakdown of the underlying sectoral energy data by stream and energy product.
Although the primary focus of Energy in Ireland is to disseminate Ireland’s definitive energy statistics data in terms of energy quantities, the energy data can also usefully be viewed through an emission lens. This emission lens previously focused on the inherent carbon dioxide (CO2) emissions arising from the combustion of energy products. We have now incorporated a more sophisticated approach, with a higher resolution view of emissions from energy-related combustion activities, in terms of carbon dioxide equivalent (CO2eq) - an approach that’s better synchronised to the EPA’s official National Inventory Submissions methodology.
What’s the added value?
Many of us will remember from our school days that the products of complete combustion are carbon dioxide (CO2) and water (H2O). Carbon dioxide emissions typically dominate, often by orders of magnitude, but there are other technology and operating condition dependant greenhouse gases (GHGs) like methane (CH4) and nitrous oxide (N2O) that also arise. That means that we can’t simply apply a ‘flat factor’ to convert CO2 into CO2eq across different sectors of the economy, or even between different technology types within the same sector. For example, the CH4 and N2O emissions profile per unit of energy from a diesel car is different from that of a diesel train, despite road diesel and rail diesel being very chemically similar.
This matters, because despite these other GHGs being emitted in much lower quantities, they also have higher global warming potentials than CO2. For example, under the Intergovernmental Panel on Climate Change’s (IPCC) 100-year time horizon global warming potential (GWP), CH4 and N2O have GWPs 28 and 265 times greater than CO2, respectively. When we take CO2, CH4 and N2O together with their GWPs applied, we can refer to them collectively in terms of CO2eq.
As well as this, despite standard international practice to exclude CO2 emissions arising from the combustion of biogenic carbon from national totals, these biofuels do have countable CH4 and N2O emissions associated with their combustion activity, and these are now included in our estimates.
Energy-related GHG emissions (CO2eq) by sector
The data visualization panel below shows how we can use this improved emission lens to view the GHG emissions associated with final energy consumption, broken out by sector. By hovering over a bubble category, you will see an interactive tooltip that shows a breakdown of the underlying energy-related emissions data by stream and energy product.
When interacting with the data visualisation, keep in mind that its data is structured according to the national Energy Balance. It provides an alternative and complimentary grouping to those based on Sectoral Emissions Ceilings (SECs) or energy-related emissions under the national Carbon Budgets, where the EPA are the competent authority. The data in the visualisation includes emissions from direct combustion of energy products within the sector and indirect emissions associated with electricity consumption which have been allocated to each sector (emissions associated with electricity transmission and distribution losses are included and fugitive emissions associated with the electricity SEC are excluded here). Emissions associated with international aviation are included in the transport sector in the visualisation too.
This methodology update has jumped our emissions estimates from CO2 to CO2eq, enabling the energy statistics team at SEAI to not only speak to the Sectoral Emissions Ceilings and Carbon Budgets, but by grouping data relevant to the energy balance, we can show how direct and indirect emissions are spread throughout the energy demand sectors. We are still working to add more features, so watch this space for more updates!
Read the Energy in Ireland report (opens in a new tab)
