3rd tank of gas @ 5,001 km
In brief (updated): We’re now at 5,001 km (about 4,977 km driven since purchase). Gas-only, we’re averaging ~1.57 L/100 km so far. If we include estimated electricity (based on the car’s reported 13.1 kWh/100 km and $0.185/kWh), our total “energy cost” works out to about $3.87 per 100 km. Compared to our old 2016 Civic (~7.9 L/100 km), that’s still roughly a two-thirds reduction in energy cost, even after winter showed up.
This post is an update to my earlier write-up (first ~4,000 km) here:
plug-in-hybrid-toyota-2025-prius-phev-real-world-usage
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What changed?
The short version: winter changed everything.
Our first few months were very EV-heavy. Since mid-November, we are consuming much more on gas. Cold weather reduces EV efficiency and range, and depending on the trip the engine can run more (heat/defrost, longer highway runs, possibly fewer perfect “short trips,” etc.). Winter tires don’t help.
Still far more efficient than the Civic.
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Jan 30, 2026:
On Jan 30, 2026 we filled the tank:
- 30.55 L
- $41.10 @ $1.345/L
- Odometer: 5,001 km
(Previous logged fills were Sep 7 and Nov 13.)
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Updated totals (Aug 9, 2025 → Jan 30, 2026)
Gas (measured at the pump)
- Distance tracked: ~4,977 km (from 24 km at purchase to 5,001 km)
- Total gas purchased: 78.06 L
- Gas-only average: 1.57 L/100 km
- Total gas spend (receipts): $111.18
- Gas-only cost: $2.23 per 100 km
Electricity (estimated — see methodology)
- Using 13.1 kWh/100 km and estimating EV kilometres, we get:
- Estimated electricity used: ~439 kWh
- Estimated electricity cost: ~$81 (at $0.185/kWh)
Total energy cost (gas + estimated electricity)
- Total energy spend: ~$192
- Total cost per 100 km: ~$3.87
“Savings vs the Civic” (apples-to-apples)
If the Civic would have done the same 4,977 km at 7.9 L/100 km, that’s about 393 L of gas. Using the weighted average gas price from our receipts so far (~$1.42/L), the Civic would have cost about $560 in gas.
- Estimated savings vs Civic so far: ~$368
- That’s roughly a 66% reduction in energy cost (again: energy = gas + estimated electricity here).
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The winter effect (why the graph suddenly gets ugly)
Looking at the car in “segments” between fills (useful, but not perfect if a fill wasn’t truly full-to-full), the trend is obvious:
- Aug 9 → Sep 7: ~1.69 L/100 km
- Sep 7 → Nov 13: ~0.92 L/100 km
- Nov 13 → Jan 30: ~2.95 L/100 km ← winter shows up loud and clear
Using the same estimation method as before (hybrid baseline + EV efficiency), the estimated EV share also shifts a lot:
- Aug→Sep: ~65% EV
- Sep→Nov: ~81% EV
- Nov→Jan: ~39% EV
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Summary:
Electricity estimation: we don’t have consistent wall metering, so we estimate kWh using:
- The car’s reported 13.1 kWh/100 km (I need to get a more recent number)
- Estimated EV kilometres (based on a reasonable hybrid-only baseline)
- Electricity priced at $0.185/kWh
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