A full hybrid (HEV) drives on electric power alone at low speed; a 48-volt mild hybrid (MHEV) never does — it merely assists the combustion engine. On the same SUV, the gap reaches 1.1 to 1.3 L/100 km and 25 g of CO₂. For a Belgian commuter covering 20,000 km a year, that adds up. Here is how much.
Full hybrid or mild hybrid: what is the real difference?
A mild hybrid replaces the conventional alternator with a reinforced starter-generator fed by a small 48-volt battery. The system cuts the engine when you lift off, helps it restart and recovers a few joules under braking. It never moves the car on its own: the battery holds less than 1 kWh and the electric motor has neither the power nor the torque for it.
A full hybrid carries a proper 40 to 100 kW electric motor and a 1 to 1.6 kWh battery, with a transmission designed to run on electricity alone. In town, below 50 km/h, a Tucson Hybrid or a Sportage HEV regularly moves with the combustion engine switched off. That is exactly where they save their fuel.
The figure that counts: Moniteur Automobile already ran the headline "fake hybrid" in its March 2019 test of the Tucson 2.0 CRDi Mild-Hybrid 48V. Seven years on, the technology has barely moved — the marketing has only got louder.
How much does a mild hybrid use against a full hybrid?
On an identical body, the WLTP gap sits between 1.1 and 1.3 L/100 km. The cleanest test is to compare the two drivetrains within the same model, from the same manufacturer: it is the only way to isolate the powertrain from everything else.
| Model (same body) | Drivetrain | WLTP consumption | WLTP CO₂ | Fuel / year* |
|---|---|---|---|---|
| Hyundai Tucson 1.6 T-GDi 48V | Petrol mild hybrid, 150 hp | 6.6 L/100 | 154 g/km | ~€2,826 |
| Hyundai Tucson 1.6 T-GDi Hybrid | Full hybrid, 239 hp | 5.5 L/100 | 129 g/km | ~€2,336 |
| Kia Sportage 1.6 T-GDi 150 DCT | Petrol mild hybrid, 150 hp | 6.8 L/100 | 155-168 g/km | ~€2,901 |
| Kia Sportage 1.6 T-GDi 239 HEV | Full hybrid, 239 hp | 5.5 L/100 | 124-135 g/km | ~€2,336 |
| Renault Austral mild hybrid 130 | Petrol mild hybrid, 130 hp | 5.2-5.6 L/100 | 118-127 g/km | ~€2,298 |
| Renault Austral E-Tech 200 | Full hybrid, 200 hp | 4.8 L/100 | ~108 g/km | ~€2,035 |
*Basis: 20,000 km/year, real consumption estimated at WLTP + 13 %, 95 E10 petrol at €1.884/L (official maximum price from the SPF Économie, the Belgian federal economy department, 13 July 2026). WLTP data: 2026 Tucson range and 2026 Sportage 5d range from Moniteur Automobile, Austral E-Tech specification sheet from Renault Belgium.
In practice that means €490 of fuel saved per year on the Tucson, €565 on the Sportage — but only €263 on the Austral. The lesson is right there: mild hybrids are not all equal. The Austral's smaller 1.3 TCe, paired with a manual gearbox, holds up far better than the Korean 1.6 turbos with their dual-clutch boxes.
What does CO₂ change on your Belgian bill?
A great deal — and mostly in the north of the country. In Flanders, the BIV (registration tax) is calculated from an exponential CO₂ formula: the value is raised to the sixth power, with a technology coefficient q of 1.245 in 2026. The result is that 25 g/km do not cost 25 g of tax; they roughly double the bill.
Applied to the two Tucsons, the official formula yields about €350 of BIV for the Hybrid (129 g) and about €1,000 for the 48V (154 g). Close to €660 of difference, paid once — but paid before your first tank. The Vlaams Belastingportaal simulator gives the exact figure per version and trim.
In Brussels and Wallonia, registration tax is still based on fiscal horsepower and vehicle age rather than directly on CO₂, so the gap there is much smaller. It is one of the rare cases where a commuter's address weighs more than their engine.
Is a mild hybrid really cheaper to buy?
Yes, but less than you would think. At Renault, the Austral mild hybrid advanced 130 starts at €32,700 against €36,800 for the E-Tech full hybrid 200: a €4,100 gap. At €263 of fuel saved per year, it would take fifteen years of commuting to pay back the full hybrid on fuel alone.
Except that fuel is not the only line item. The full hybrid comes with an automatic gearbox as standard, 70 extra horsepower, 10 to 19 g less CO₂ — and a better residual value, as our analysis of SUV depreciation in Belgium shows. At Hyundai and Kia, where the consumption gap reaches 1.1 to 1.3 L, the payback drops below six years.
What we would avoid: paying a "hybrid" premium for a mild hybrid sold as electrification. The 48V badge on the tailgate changes neither your fuel bill nor your tax bill.
Which one for a commuter covering 20,000 km a year?
It all hinges on the motorway share. If more than half of your kilometres are urban, suburban or on secondary roads, the full hybrid wins outright: that is precisely the terrain where it runs with the engine off. Over 20,000 km, stack the €490 to €565 of fuel on top of the €500 to €660 of Flemish BIV, and the purchase-price gap is absorbed in three to six years.
If your commute is the E40 between Ghent and Brussels, or the E411 towards Namur at a steady 120 km/h, the maths change. At constant speed the full hybrid has no braking to recover and no electric phase: its advantage halves, as we measured in our ranking of the most fuel-efficient SUVs. A keenly priced petrol mild hybrid then becomes defensible again — provided you do not pay for the badge.
On the Belgian market, one last point settles the company-car debate: since 1 January 2026, only zero-CO₂ vehicles remain deductible for a new order. Full hybrids and mild hybrids sit in the same tax bracket — which makes the choice a private buyer's decision again.
Which hybrid SUVs should you avoid?
Three cases, no nuance. The diesel mild hybrid first: ADAC measured the Hyundai Tucson 1.6 CRDi 48V at 6.1 L/100 km in real driving (5.8 L in town, 7.4 L on the motorway) against a WLTP claim of 5.0 L. Add the price per litre of diesel, the trajectory of the Brussels and Antwerp low-emission zones, and depreciation: not a single box is ticked.
The mild hybrid priced like a full hybrid next. Some high-end 48V trims cost more than an entry-level full hybrid: you pay more for a system that burns more and is taxed more.
The PHEV without a home charger last, still the worst choice in the segment for a commuter — with a flat battery it hauls 250 to 300 kg for nothing. If you are still torn between the three technologies, our hybrid vs electric SUV comparison lays out the full calculation, and our pick of the best hybrid SUV in Belgium names the models worth keeping.
Frequently asked questions
A mild hybrid (MHEV, usually 48 volts) adds a beefed-up starter-generator and a small battery: it assists the combustion engine on pull-away and recovers a little energy under braking, but the car never runs on electricity alone. A full hybrid (HEV) has a proper electric motor and a bigger battery: it pulls away, manoeuvres and drives around town in full electric mode, without ever plugging in. In short: a mild hybrid is an assisted combustion car, a full hybrid is a genuine hybrid drivetrain.
On an identical SUV the gap is around 1 to 1.3 L/100 km under WLTP. The Hyundai Tucson 1.6 T-GDi 48V is rated at 6.6 L/100 km, against 5.5 L for the Tucson 1.6 T-GDi Hybrid. The Kia Sportage 1.6 T-GDi 150 mild hybrid claims 6.8 L, against 5.5 L for the Sportage 239 HEV. In real driving, add 10 to 15 % to both figures — but the gap between them holds.
It is worth it in two cases only: if you drive mostly on the motorway (where the full hybrid loses its edge), and if the purchase price is your hard constraint. Everywhere else the higher CO₂ figure is paid at registration — especially in Flanders — and the extra fuel wipes out the initial saving within a few years. For a mixed town-and-road commuter, the full hybrid remains the rational choice.
The Flemish BIV (registration tax) is based on an exponential CO₂ formula (technology coefficient q = 1.245 in 2026). Applied to a petrol SUV, it produces roughly €350 at 129 g/km (Tucson Hybrid) and roughly €1,000 at 154 g/km (Tucson 1.6 T-GDi 48V). Those 25 g therefore cost close to €660 at registration, before your first tank of fuel. The official Vlaams Belastingportaal simulator gives the exact figure per version.
No, and it is the worst compromise in the segment. ADAC measured the Hyundai Tucson 1.6 CRDi 48V at 6.1 L/100 km in real driving (5.8 L in town, 7.4 L on the motorway), against a WLTP rating of 5.0 L. Diesel still costs more per litre in Belgium, the low-emission zones (LEZ) keep tightening and diesel depreciation is accelerating. Moniteur Automobile already called the diesel mild-hybrid Tucson a 'fake hybrid' back in March 2019: the verdict has aged well.
If more than half of your kilometres are urban or suburban, take the full hybrid: over 20,000 km the consumption gap is worth about €500 of fuel a year at the maximum price of 95 E10 petrol (€1.884/L on 13 July 2026), plus €500 to €660 of registration tax saved in Flanders. If you spend your commute on the E40 or the E411 at a steady 120 km/h, the gap halves and a keenly priced petrol mild hybrid becomes defensible again.
No. Since 1 January 2026, only zero-CO₂ vehicles remain deductible for new company-car orders. Full hybrids and mild hybrids therefore fall into the same tax bracket: neither can be justified on deductibility. The choice between them is once again a private buyer's decision, settled on fuel, regional CO₂ taxation and resale value.
We dig through the Belgian market data — TÜV reliability, real-world ADAC consumption, company-car taxation, list prices — to call it straight. No brand pays us.