CO₂ Emissions

Greenhouse gas emissions come from many different sources. The two most important from the point of view of human contribution to climate change are carbon dioxide (CO₂) and methane (CH₄). Carbon dioxide mainly comes from the burning fossil fuels for energy. In Ireland methane mostly comes from agriculture livestock. Other sources of greenhouse gas emissions include industrial processes such as cement manufacture, fertiliser spreading in agriculture and refrigeration gases. CO₂ from burning fossil fuels accounted for 57% of all greenhouse gas emissions in Ireland during 2021, down from 65% in 2005.

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 43% 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

The biggest source of greenhouse gas emissions in Ireland is CO₂ emissions from the burning of fossil fuels by the non-ETS sector, for example in homes and cars. These made up 38% of all greenhouse gas emissions in Ireland in 2021, and 49% of all non-ETS greenhouse gas emissions.

Ireland is unusual compared to other EU countries because greenhouse gas emissions from agriculture make up a much larger share of our emissions. In 2021 agriculture was responsible for 37.5% of all greenhouse gas emissions, and for 47% of all non-ETS greenhouse gas emissions.

Other greenhouse gas emissions in the non-ETS sector, for instance from refrigeration or from landfill gases, made up 3.2% of all greenhouse gas emissions, or 4% of non-ETS emissions in 2021.

Companies in the ETS were responsible for 22% of Ireland's greenhouse gas emissions in 2021.

Ireland's target for 2020 was for non-ETS emissions to be 20% lower than they were in 2005. Ireland failed to meet this target. In 2020 our non-ETS emissions were just 7% below 2005 levels. Energy related non- ETS emissions were only 16% below 2005 levels despite a large drop in transport emissions in 2020 due to the COVID-19 pandemic . Agriculture related non-ETS emissions were 8% higher than 2005 levels.

Ireland's new target for 2030 is for non-ETS emissions to be 30% lower than they were in 2005. In 2021 our non-ETS emissions were 5% below 2005 levels. Energy related non- ETS emissions were 15% below 2005 levels . Agriculture related non-ETS emissions were 11% higher than 2005 levels.

Energy-related CO2 emissions

SEAI compiles statistics on energy use, which allows us to calculate the amount of carbon dioxide released on burning fossil fuels. The following sections give more information on carbon dioxide emissions from energy use in Ireland.

The Environmental Protection Agency compiles data on all greenhouse gas emissions for Ireland, including agriculture and industrial processes, more information available on the EPA website.

Some fuels emit more CO₂ per unit of energy than others. For instance, coal and peat emit high levels of CO₂ per unit of energy used, but natural gas emits less. All renewable energy sources are considered zero carbon. Therefore, changes in the mix of fuels used over time can increase or reduce emissions.

Almost 55% of all energy-related CO₂ emissions in 2021 were from burning oil products such as petrol and kerosene. Oil is such a large share because transport makes up a very large share of energy use in Ireland and virtually all energy used for transport is from oil. More Irish homes also use oil for heating than any other fuel, which is unusual compared to other EU countries.

Coal and peat were responsible for 14% of all energy-related CO₂ emissions in 2021, mostly from electricity generation and in homes.

High emissions from transport

Transport is by far the largest source of energy-related CO₂ emissions in Ireland. Before the COVID-19 pandemic it was responsible for over 40% of energy related CO₂ 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 CO₂ emissions in 2021.

Electricity generation and households are the next biggest sources of energy-related CO₂ emissions. Electricity generation was responsible for 29% of energy related CO₂ emissions in 2021 and fuel use in homes was responsible for 19%.

Ireland is unusual in that households emits more CO₂ 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 CO₂ emissions, these are dominated by transport, which was responsible for 52% in 2021. The next biggest share was residential at 33%. Because most industry is under the ETS, industry made up just 5% of energy-related non-ETS CO2 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 CO₂ emissions split into the three main modes of energy: electricity, heat and transport. In 2021, heat remained the largest share of energy-related CO₂ emissions at 37%.

Transport had caused most CO₂ emissions every year from 2013 to 2019, but fell by 26% in 2020 because of the COVID-19 pandemic. Its share returned to growth in 2021 making up 34% of energy related CO₂ emissions.

Electricity emissions grew by 17% in 2021, due to outages in our gas-fired electricity generators and a particularly poor year for wind generation in 2021, which forced us onto higher carbon coal- and oil-fired electricity generators to compensate.. Electricity was responsible for 29% of energy-related CO₂ emissions.

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.

Ireland’s economy grew rapidly from the early 1990s up until the global financial crisis in 2007. Ireland’s economy then contracted sharply between 2007 and 2010, and continued to shrink until 2012. From 2012 it returned to strong growth.

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.

In 2021 economic growth, energy use and energy related CO₂ emissions all grew, after falling in 2020 due to the impacts of the COVID-19 pandemic.