Ireland used to be a diesel country. Not in a vague, directional sense. In a hard, numerical, seven-out-of-ten-new-cars sense. In 2016, diesel accounted for approximately 70% of all new passenger car registrations in Ireland. That was the peak. By 2024, the share had dropped to around 22.9%. In absolute numbers, diesel registrations fell from over 100,000 units per year to roughly 28,000. This is the fastest fuel-type decline in Irish automotive history, and understanding why it happened matters for understanding where the market goes next.
How Diesel Got to 70%
The rise of diesel in Ireland was a policy-driven phenomenon. In 2008, the government restructured Vehicle Registration Tax (VRT) and motor tax to be based on CO2 emissions per kilometre rather than engine size. Diesel engines, which produce less CO2 per kilometre than equivalent petrol engines, suddenly became cheaper to tax. Overnight, the economic incentive flipped. Buyers who might have chosen petrol found that diesel was cheaper to run, cheaper to tax, and delivered better motorway fuel economy. By 2012, diesel had crossed 60%. By 2016, it peaked at 70%.
What Went Wrong
Three things converged. First, the Volkswagen emissions scandal broke in September 2015. While its immediate market impact was small, the long-term narrative damage was severe. Diesel went from being the "smart" choice to the "dirty" choice in public perception. Media coverage of NOx pollution, particulate matter, and city-centre diesel bans across Europe reinforced this shift relentlessly.
Second, the introduction of the WLTP (Worldwide Harmonised Light Vehicles Test Procedure) testing regime in 2018 and 2019 changed the CO2 ratings for many diesel models. Under the older NEDC test cycle, diesels looked very clean on paper. Under WLTP, which is more realistic, their advantage shrank. Some diesel models saw their official CO2 figures jump by 20% or more, pushing them into higher tax bands and eroding the financial case for diesel.
Third, hybrid alternatives arrived. Toyota's hybrid lineup offered similar or better real-world fuel economy to diesel without any of the reputational baggage. Petrol-hybrid models went from near-zero share in 2016 to over 20% of the market by 2024. For many buyers, hybrid was simply a less complicated choice.
The Year-by-Year Collapse
The numbers tell the story clearly. Diesel share: 70% in 2016, 65% in 2017, 58% in 2018, 48% in 2019, 42% in 2020, 36% in 2021, 30% in 2022, 26% in 2023, and 22.9% in 2024. Each year shed between 3 and 7 percentage points. There was no recovery year, no pause, no plateau. Just a continuous, accelerating decline.
Is Diesel Dead?
Not quite. Commercial vehicles and larger SUVs still skew heavily diesel, and the used car market remains flooded with diesel stock. But for new car sales, the direction is irreversible. Most manufacturers have stopped developing new diesel engines for passenger cars. By 2027, it is likely that fewer than 15% of new Irish registrations will be diesel, and the fuel type will functionally be limited to a handful of large vehicle segments.
See the full diesel-to-electric transition visualised on AutoNergy. The Electric Cars streamgraph shows exactly how diesel's share was absorbed by hybrid, PHEV, and battery electric powertrains year by year.