Energy-related greenhouse gas (GHG) emissions

In 2024, SEAI moved its energy-related emission reporting from mega tonnes of carbon dioxide (MtCO₂) to mega tonnes of carbon dioxide equivalent (MtCO₂eq). This methodology update better aligns SEAI’s reporting of energy-related emissions to those in the national carbon budgets, and to the EPA’s Greenhouse Gas (GHG) Emissions Inventory, compiled in accordance with IPCC guidelines. 

The greenhouse gases (GHGs) covered within these CO₂eq estimates include carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O), gases which are known to contribute to the warming of the earth’s atmosphere to varying extents over a given timeframe.

Emissions from large companies (ETS)

Any company or body within the EU that emits a large amount of greenhouse gas emissions is included in the Emissions Trading System, commonly known as the ETS for short. This includes large industries, electricity generators, and the aviation industry. The ETS ensures that all these companies will collectively reduce their emissions by 62% by 2030 compared to 2005.

More on EU ETS

Emissions from homes, small businesses and farms (Non-ETS)

All greenhouse gas emissions that are not from companies in the ETS are called non-ETS emissions. Non-ETS emissions include greenhouse gas emissions from homes, cars, small businesses and agriculture. These are often collectively called the non-ETS sector.

Non-ETS emissions are important because each country in the EU has mandatory targets to reduce non-ETS emissions by 2030.

More on EU non-ETS emissions targets

Large share of fossil fuels and agriculture

One of the biggest sources of greenhouse gas emissions in Ireland is from the burning of fossil fuels by the non-ETS sector, for example in homes and cars.  Energy-rated emissions in the non-ETS sector made up 39.5% of all greenhouse gas emissions in Ireland in 2024.

Ireland is unusual compared to other EU countries because greenhouse gas emissions from agriculture make up a much larger share of our emissions. In 2024 agriculture was responsible for 36% of all greenhouse gas emissions.

Companies in the ETS were responsible for 21.1% of Ireland's greenhouse gas emissions in 2024.

The EU Effort Sharing Regulation and implementing decision requires Ireland to reduce its non-ETS emissions by at least 42% by 2030, compared to a 2005 baseline. In 2024 our non-ETS emissions were 11% below 2005 levels. Energy related non- ETS emissions were 18% below 2005 levels . Agriculture related non-ETS emissions were 3% higher than 2005 levels.

High emissions from transport

Transport is by far the largest source of energy-related CO₂eq emissions in Ireland. Before the COVID-19 pandemic it was responsible for 32% of energy related CO₂eq emissions in 2019. During 2020, transport was the sector whose energy use was most impacted by the public health restrictions taken to combat COVID-19, and transport energy use fell by 26%. By the middle of 2021 transport activity and energy use had mostly returned to pre-pandemic levels. Transport accounted for 34% of energy related CO₂eq emissions in 2024.

Ireland's national energy-related emissions, as reported in the EPA’s Greenhouse Gas (GHG) Inventory, do not include emissions associated with international aviation or international maritime transport. However, for context, SEAI estimates that Ireland’s emissions from international aviation accounted for 10% of national energy-related emissions. 

Electricity generation and households are the next biggest sources of energy-related CO₂eq emissions. Electricity generation was responsible for 22% of energy related CO₂eq emissions in 2024 and fuel use in homes was responsible for 16%.

Ireland is unusual in that households emits more CO₂eq than industry. This is because Ireland does not have as much heavy industry, such as steel or fertiliser manufacture, compared to other countries. Also we use larger amounts of carbon intensive fuels such as coal, peat and oil in our homes, compared to other EU countries.

Tackling transport emissions crucial for Ireland

To tackle climate change, EU countries have agreed to reduce greenhouse gas emissions from the non-ETS sector in each country.

When looking at the non-ETS sector we exclude greenhouse gas emissions from electricity and large companies, as these are counted under the Emissions Trading System. About half of non-ETS emissions are from agriculture and the other half are energy related.

Looking at the energy-related Non-ETS CO₂eq emissions, these are dominated by transport, which was responsible for 54.6% in 2024. The next biggest share was residential at 26.5%. Because most industry is under the ETS, industry made up just 5.2% of energy-related non-ETS CO₂eq emissions.

For Ireland to reduce our non-ETS emissions and meet our targets for 2030, we need to reduce our greenhouse gas emissions from transport and homes, as well as agriculture.

We can also look at energy-related CO₂eq emissions split into the three main modes of energy: electricity, heat and transport. In 2024, heat had the largest share of energy-related CO₂eq emissions at 38.3%.

Transport accounted for 37.6% of energy-related CO₂eq emissions, with electricity responsible for the remaining 24.1%.

Energy use is usually linked to economic activity. A growing economy leads to more goods being produced, purchased, transported, and more disposable income for people spend on travel or on heating their homes.

GDP is the most commonly used indicator for economic growth but in Ireland GDP can be disproportionately affected by the accounting of large multinationals. An alternative measure of economic activity is Modified Domestic Demand (MDD), which has been developed by the Central Statistics Office. We use MDD to measure economic growth, as it gives a better reflection of activity in the economy that drives energy use.

In Ireland, transport is the sector whose energy use is most sensitive to economic growth. Transport experienced the largest reduction in energy use during the recession and the largest growth since 2012. The sector that has contributed most to the increase in transport growth since 2012 has been aviation.

In other sectors of the Irish economy energy use is not as closely tied to the economy. Ireland's economy is more based on the services sector than on manufacturing. Unlike most manufacturing, the services sector has lower energy use per unit of value added, and can significantly increase the value of its output without leading to a large increase in energy use.