Choosing the type of fuel is one of the first decisions you make when buying a car. There is no single “best” option for everyone: it depends on how you plan to use the vehicle, where you drive, how many kilometers you travel per year, and your budget.
Types of Fuel
In Spain, in 2026, the following powertrain options are available:
- Petrol
- Diesel
- HEV (Hybrid Electric Vehicle) – non-plug-in hybrid
- PHEV (Plug-in Hybrid Electric Vehicle) – plug-in hybrid
- BEV (Battery Electric Vehicle) – fully electric
- LPG (Liquefied Petroleum Gas)
- CNG (Compressed Natural Gas)
Below, you will find a clear guide to understanding each technology and determining which one may best suit your needs.
Petrol
It is usually a good option if:
- You drive few kilometers per year (under 15,000 km).
- You mainly use the car in the city.
- You are looking for the lowest initial purchase price.
Modern petrol engines are efficient and quieter than diesel engines. However, fuel consumption tends to be slightly higher if you frequently drive long distances on highways.
What does it mean for a car to run on petrol?
It means the vehicle has an internal combustion engine that burns petrol inside the cylinders through a spark generated by a spark plug.
Simplified process:
- Air and petrol enter the cylinder.
- The mixture is compressed.
- The spark plug generates a spark.
- Controlled combustion occurs, moving the piston and generating motion.
Mechanically, it is simpler than a diesel engine.
Why is it often better for city driving?
Petrol engines are recommended when the vehicle is used mainly in urban environments, where trips are short, include frequent stops, and the engine does not operate continuously under high load.
Petrol engines reach optimal operating temperature more quickly, reducing wear during short trips. They also do not require the complex emissions systems found in diesel vehicles (e.g., DPF – Diesel Particulate Filter).
Why do petrol cars usually have a lower purchase price?
- The engine is simpler than a modern diesel engine.
- Emissions treatment technology is less complex.
- There is a broad supply in the used car market.
Diesel
Diesel vehicles are typically more suitable if:
- You drive many kilometers per year (over 20,000 km).
- You mainly use the car on highways or motorways.
Diesel engines consume less fuel per kilometer, but vehicles tend to be more expensive and may face stricter environmental restrictions in the future.
What does it mean for a car to run on diesel?
Instead of using a spark plug, air is compressed to such a high level that diesel fuel self-ignites under pressure. This produces a more progressive combustion, generating sustained pressure on the piston and therefore greater torque.
This allows:
- Higher energy efficiency (more usable energy per liter).
- Greater torque (more pulling power at low RPM).
As a result, diesel engines typically deliver better fuel efficiency per liter and are often recommended for highway driving.
Why do diesel engines require emissions control systems?
Diesel combustion produces higher levels of:
- Nitrogen oxides (NOx)
- Particulate matter (soot)
These pollutants are especially problematic for urban air quality. With Euro 5 and Euro 6 regulations, manufacturers were required to implement systems to reduce emissions.
Main diesel emissions systems:
-
<u>EGR (Exhaust Gas Recirculation):</u> recirculates part of the exhaust gases to reduce NOx formation.
-
<u>DPF (Diesel Particulate Filter): </u>traps soot particles and burns them into ash (regeneration process).
-
<u>SCR (Selective Catalytic Reduction) with AdBlue:</u> AdBlue is injected into the exhaust system, chemically converting NOx into nitrogen and water vapor.
These systems perform best during longer journeys at stable temperatures, making diesel generally more suitable for highway use than city driving.
HEV (Hybrid Electric Vehicle) or Non-Plug-In Hybrid
A non-plug-in hybrid combines a petrol engine with an electric motor and a battery that recharges automatically through regenerative braking.
In most traditional HEVs, batteries are relatively small and not designed to power the vehicle independently for long distances. The electric motor assists the petrol engine, reduces fuel consumption, supports acceleration at low speeds, and recovers energy when braking.
Ideal if:
- You mainly drive in the city, due to low urban consumption.
- You want the ECO environmental label (most HEVs in Spain qualify).
They typically have a higher price than conventional petrol cars, as they include additional electric components and hybrid management systems.
When does it use petrol vs electric power?
The system operates automatically:
- At low speeds and during gentle acceleration → electric mode.
- Under higher demand → petrol engine.
- During braking → energy recovery (regenerative braking).
No driver intervention is required.
Why is it well-suited for urban driving?
- Frequent braking allows constant energy recovery.
- Low-speed driving favors efficient electric operation.
Urban consumption can be 20–30% lower than an equivalent petrol vehicle.
PHEV (Plug-In Hybrid Electric Vehicle)
Plug-in hybrids combine:
- A petrol engine
- A more powerful electric motor
- A larger battery capable of powering the car for dozens of kilometers in electric mode
They can be recharged:
- Through regenerative braking
- By plugging into the grid
They typically offer 40–100 km of electric range (depending on model and real conditions).
BEV (Battery Electric Vehicle) or Fully Electric
Fully electric vehicles operate 100% on battery power.
Ideal if:
- You drive predictable urban or daily routes and have access to charging points.
- You want the ZERO emissions label (all approved BEVs in Spain qualify).
Charging infrastructure continues to grow in 2026, but analyzing range and charging availability remains essential.
What range is adequate?
Recommended real-world range depends on usage:
- Urban use: 250–350 km may be sufficient.
- Mixed use: 350–450 km is advisable.
WLTP range is laboratory-based. In practice, real range may be 10–30% lower due to speed, terrain, climate control use, and temperature.
Cost per Kilometer: Petrol vs Electric (Spain 2026)
Estimated average values in Spain:
- Petrol: €1.60/liter
- Average petrol consumption: 6.5 L/100 km
- Home electricity price: €0.22/kWh
- Public charging price: €0.50/kWh
- Average electric consumption: 16 kWh/100 km
<u>A. Refueling petrol</u> ≈ €0.104/km → €10.4 per 100 km
<u>B. Charging at home</u> ≈ €0.035/km → €3.5 per 100 km
<u>C. Public charging</u> ≈ €0.08/km → €8 per 100 km
Conclusion:
- Petrol is approximately 200% more expensive than home charging.
- Petrol is approximately 30% more expensive than public charging.
The main economic advantage of electric vehicles lies in home charging.**
LPG and CNG
LPG and CNG are adapted petrol engines capable of running on both petrol and gas.
Advantages:
- Lower fuel cost per kilometer
- ECO environmental label
Disadvantages:
- Limited refueling infrastructure
- Limited long-term development in Europe
Strategically, LPG and CNG are no longer a central focus of the European automotive industry, which is prioritizing electrification.
Spanish Market Data (2026)
New registrations:
- Fully electric: ~10–15%
- Hybrids (HEV + PHEV): ~30–35%
- Petrol + diesel: ~50–55%
Total fleet:
- Fully electric: ~2–4%
- Hybrids: ~8–10%
- Petrol and diesel still dominate.
Final Conclusion
Choosing a fuel type is not just about trends or technological hype. It is a practical and economic decision based on your real usage.
Analyzing how many kilometers you drive, where you drive, whether you can charge at home, and how regulations may evolve in your city is essential.
The best choice is not the newest one, but the one that best fits your reality.
