When you visit the public SIMI Motorstats portal and apply a Petrol filter for 2025, the "Passenger Cars By Make" table renders empty. Apply a Hybrid filter and the same thing happens. Apply Diesel and you see model-level rows but no make-level breakdown. The fully populated per-brand-per-fuel matrix sits behind a SIMI trade-member login.
That data exists in the public domain through a different door: the Central Statistics Office of Ireland's PxStat open data API, table TEM28 ("New Private Cars Licensed for the First Time"). CSO sources the National Vehicle and Driver File (NVDF) maintained by the Department of Transport. They publish the full Statistic x Month x Fuel x Make+Model matrix as a JSON-stat array. No login, no rate limit.
What's in TEM28
The current table covers January 2024 through April 2026 at monthly granularity. Each cell records a count of new private cars licensed for the first time in Ireland for that (year, month, fuel type, make+model) tuple. The fuel taxonomy is eight categories: Petrol, Diesel, Petrol and electric hybrid (HEV), Diesel and electric hybrid, Petrol or Diesel plug-in hybrid electric (PHEV), Electric (BEV), Other fuel types, and Ethanol and petrol.
The make+model dimension carries 321 distinct vehicles, from Alfa Romeo Giulietta through Xpeng G6. Aggregating to manufacturer level gives roughly 40 brands per year with non-zero registrations.
What the per-brand matrix looks like in 2025
Once aggregated by make and divided by each brand's total registrations, you get the actual fuel-mix fingerprint of every manufacturer doing real volume in Ireland. The 2025 highlights:
- Toyota: 83% Hybrid, 10.9% PHEV, 3.1% Petrol, 2.9% Electric. The most hybrid-skewed major brand on the Irish road; almost no petrol-only Toyotas are being licensed any more.
- BMW: 62.5% PHEV (driven by the iX, i4, and 3 Series PHEV lineup), 14.9% Electric, 14.4% Petrol, 7.9% Diesel. Highest PHEV share of any volume brand.
- Skoda: 54% Diesel, 30.6% Petrol, 12.7% Electric, 1.9% PHEV. The diesel hold-out for buyers who still want a Kodiaq or Octavia diesel.
- Audi: 49.4% Diesel, 17.7% Petrol, 13.2% Hybrid, 12.5% PHEV, 7.2% Electric. Premium diesel sticks around.
- Volkswagen: 29.7% Diesel, 39% Petrol, 23% Electric, 8.4% PHEV. The most balanced fuel mix of any top-5 brand.
- Tesla: 100% Electric (by definition).
SIMI vs CSO, do the totals match?
The percentages match almost exactly, but the absolute unit counts differ by ~6-8%. For 2025 the SIMI annual total is 124,954 private cars; the CSO TEM28 sum for the same year is 116,927. The gap shows up because SIMI counts new car registrations through the dealer network whereas CSO TEM28 counts new private cars licensed for the first time on the NVDF. The two methodologies differ on borderline M1/N1 vehicles, on the few "pre-registered grey imports" path, and on the timing-of-licensing lag (CSO consolidates from NVDF on a slower cycle, which is why the 2026 YTD gap is larger).
For the brand x fuel slice, the share percentages between the two sources are within 1 percentage point on every fuel for 2025: Petrol 25.52% (SIMI) vs 26.37% (CSO), Hybrid 22.85% vs 22.01%, Electric 19.20% vs 19.13%, Diesel 17.37% vs 16.21%, PHEV 15.06% vs 15.09%. The ratios are robust.
How AutoNergy uses both sources
The Ireland dashboard now layers both authoritative open sources transparently. Headline registrations, monthly bars, and the fuel-shift streamgraph all use SIMI Motorstats numbers, because those are the industry-standard quote used by every Irish motor press release. The brand x fuel deep-dive matrix uses CSO TEM28 data for 2024-2026, because CSO publishes what SIMI gates. For 2015-2023 the matrix falls back to live SIMI YTD-April Diesel data (scraped from the public stats.simi.ie filter) plus AutoNergy estimates anchored to the year's SIMI total fuel-mix share for the remaining fuels. CSO TEM28 does not go back beyond 2024.
Try it
Open the Ireland dashboard, expand the "Diesel collapsed. Electric arrived." fuel card, and scroll to the Brand x Fuel Mix table. Every cell that reads against Diesel, Petrol, Hybrid, PHEV, or Electric for 2024-2026 is a real CSO number sourced from the open API, not an estimate. The source line at the bottom of the table tells you exactly which years and which fuels are live versus estimated.
If you want to pull the data yourself, the endpoint is: GET https://ws.cso.ie/public/api.restful/PxStat.Data.Cube_API.ReadDataset/TEM28/JSON-stat/2.0/en