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 2020, 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 21% by 2020 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 in 2020 and 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 39% of all greenhouse gas emissions in Ireland in 2020, 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 2020 agriculture was responsible for 37% 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% of all greenhouse gas emissions, or 4% of non-ETS emissions in 2020.

Companies in the ETS were responsible for just over 20% of Ireland's greenhouse gas emissions in 2020.

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 7% 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.

Over half of all energy-related CO₂ emissions in 2020 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 11% of all energy-related CO₂ emissions in 2020, mostly from electricity generation and in homes.

Renewable energy to avoid emissions

Using renewable energy for heat, electricity and transport reduced emissions by 6.6 million tonnes CO₂ (MtCO₂) in 2020. This is more than the CO₂ emissions of all private cars (1.4 million) on the road.

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%. Despite this drop, transport still had the largest share of energy related CO₂ emissions in 2020. The reduction in transport energy use will not be long lasting, by the middle of 2021 transport activity and energy use had mostly returned to pre-pandemic levels.

Electricity generation and households are the next biggest sources of energy-related CO₂ emissions. Electricity generation was responsible for 25% of energy related CO₂ emissions in 2020 and fuel use in homes was responsible for 21%.

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 51% in 2020, despite the large drop in transport emissions due to COVID-19 restrictions. The next biggest share was residential at 35%. Because most industry is under the ETS, industry made up just 2% 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 2020, heat rose to the largest share of energy-related CO₂ emissions at 41%.

Transport had caused most CO₂ emissions every year from 2013 to 2019, but fell by 26% in 2020 because of the COVID-19 pandemic. Despite this dramatic reduction, it still made up 34% of energy related CO₂ emissions.

Electricity emissions fell by 6% in 2020, because peat-fired generation fell and wind generation rose. Electricity was responsible for 25% 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.

Between 2011 and 2014 the economy grew, energy use remained flat and energy-related CO₂ emissions fell. Some reasons for this included:

• Record high energy prices
• Increased use of renewable energy technologies
• Higher efficiency vehicles, homes and businesses

Recent emissions trend

In 2015 and 2016, the economy continued to grow. At the same time energy use and associated CO₂ emissions started to rise again, albeit at a slower rate than economic growth. Some reasons for this included:

• A fall in energy prices
• Economic growth
• Increased transport demand 

Emissions fell in 2017 and in 2018, despite a growing economy. This was mainly due to lower use of coal in electricity generation and increased renewable generation mainly from wind.

In 2020 economic growth, energy use and energy related CO₂ emissions all fell, due to the impacts of the COVID-19 pandemic.