Transport

*This webpage will be retired soon and replaced by new webpages with interactive data panels. Please visit the 'Annual Energy Data - Transport' webpage to access the updated content.

Private cars

Private car energy use clearly dominates and accounted for over 40% of transport energy use in 2022. Private car energy use declined briefly during the recession in 2009 and 2010 but returned to growth in 2011. It peaked in 2015 but remained relatively flat up until 2019, before the sharp drop in 2020. The levelling off of private car energy demand between 2015 and 2019 was due to a combination of the amount of kilometres driven levelling off and the efficiency of the car stock improving.

Aviation and HGV

Aviation energy use is notable in that it usually makes up a large share of transport energy use in Ireland, particularly since 2000, but can be severely affected by external factors, such as recessions or the COVID-19 pandemic. International aviation energy consumption fell by 44% between 2007 and 2012 during the recession. It returned to strong growth after 2012, reaching an all-time-high in 2019, 6.8% above the previous 2007 peak, before the dramatic fall in 2020. In 2022, consumption in international aviation had returned to around the same level as 2017.

Heavy goods vehicles (HGV) energy use also saw a large reduction during the recession, falling by 49% between 2007 and 2013. It has increased since, but remains below the 2007 peak. These changes are due to changes in the amount of goods transported.

Increase in kilometres driven

We use vehicle-kilometres (vkm) to measure the activity of private cars. This is the sum of all kilometres driven by all private cars. The total number of vehicle-kilometres travelled declined following the economic crash (during 2009 and 2010) but returned to growth soon after in 2011. Total vehicle-kilometres continued to grow until the dramatic fall in 2020 due to travel restrictions during COVID-19, returning to growth in 2021 and 2022.

CO₂ emissions for new cars

For the average new car purchased, CO₂ emissions per kilometre fell by 32% between 2007 and 2016, reaching 112.4 g CO₂/km in 2016. This was due to car taxation changes, and EU obligations for manufacturers to reduce fleet emissions. By 2019 however, the average CO₂ emissions per kilometre had increased again by almost 5% --- partly due to the increasing share of SUVs. Subsequently, the CO₂ emissions per kilometre of cars purchased during 2020 reversed, falling to 111.0 gCO₂/km. This 2020 result finishes the use of the NEDC (New European Driving Cycle) test procedure. The timeseries breaks in 2021 and from January 2021 a new test methodology called the Worldwide Harmonised Light Vehicle Test Procedure (WLTP) came into force for all new cars. This new test is intended to better reflect real-world driving profiles.

New test procedures

A standardised laboratory test procedure determines the carbon emissions ratings of new cars. The on-road factor is the difference between test emissions and emissions in real world driving conditions. Evidence shows that the on-road factor has increased dramatically in recent years. Real world fuel consumption and carbon emissions are now much greater than test values.

The new procedure, the Worldwide Harmonised Light Vehice, aims to reduce the difference between test results and real world performance.

The above chart shows the trends in transport's final energy use split by fuel type since 2005.

Fuel consumption in transport is often closely aligned to the mode of transport used: jet kerosene is used for air transport; fuel oil for shipping; petrol and liquefied petroleum gas (LPG) are almost exclusively used for road transport; and diesel is used for road transport, domestic water navigation, and rail.

The most important point to note is that transport remains almost completely dependent on fossil fuels, particularly oil products. This lack of fuel diversity is unique amongst the energy using sectors. Renewables made up a very small share of transport energy use in 2022. Electricity also remains a small share of transport energy use, which is split between electric rail (Dublin Area Rapid Transit (DART) and Luas) and electric vehicles (mostly private cars). This has meant that there has been very little decarbonisation of the transport fuel mix to date, with transport CO₂ emissions remaining tightly coupled to energy use.

Recent growth

Activity of Heavy Goods Vehicles (HGV) is best measured by tonne-kilometres (tkm). Tonne-kilometres are the weight of the freight that is transported multiplied by the distance it is transported over. The CSO track HGV activity in their annual "Road Freight Survey".

HGVs were responsible for the largest share of the decrease in transport sector energy demand between 2007 and 2013. This was primarily the result of reduced activity in the sector, which contracted more sharply than economic growth after the economic crisis of 2008. By 2013 HGV activity was down 51% compared to the peak in 2007. It returned to growth from 2014 but by 2022 it was still below the 2007 level.

Although HGV activity was less affected by COVID-19 travel restrictions than private cars or aviation, the amount of tonne-km still fell in 2020. This was nearly twice the reduction seen total economic activity, as measured by modified domestic demand. HGV activity returned to growth in 2021.