Horse Amorfo motor reaches 98.2% efficiency

Horse, the joint powertrain venture formed by Renault and Chinese car maker Geely, has announced a technical milestone. Its new electric motor, called Amorfo, is said to achieve 98.2% efficiency, taking it close to the practical physical limit. That headline figure is underpinned by a series of unusual engineering choices – and raises the prospect of noticeably more economical hybrid and electric cars in the years ahead.

The French-Chinese partnership behind it

Horse is an independent company established by Renault and Geely to bring together powertrain technology, including combustion engines, hybrid systems and electric motors. While European brands have recently concentrated heavily on dedicated electric platforms, Geely has been steadily developing its powertrain expertise behind the scenes. The Amorfo motor emerges directly from this overlap.

The unit is primarily intended for hybrid vehicles, where an internal-combustion engine works alongside an electric motor. Range-extender layouts and particularly efficient plug-in hybrids are also key targets. Producing 190 PS and 360 Nm of torque, the Amorfo sits firmly in the mid-range on technical grounds rather than in the supercar class. Its significance comes from efficiency, not outright power.

According to the manufacturer, Horse's Amorfo motor achieves 98.2% efficiency and halves the internal losses of conventional electric motors.

The material innovation: amorphous steel in the stator

At the centre of the motor is the stator: the stationary component that generates the magnetic field for the rotor. Stators are normally made from thin sheets of crystalline electrical steel. Horse has instead chosen amorphous steel.

What exactly is “amorphous” steel?

Unlike conventional steel, the atoms in an amorphous metal are arranged irregularly, much like those in glass. There is no orderly crystal lattice. This substantially changes its magnetic properties: magnetisation losses are lower and eddy currents can be controlled more effectively. Those eddy currents account for a noticeable share of the energy lost in conventional electric motors.

In the Amorfo motor, the stator laminations are only 0.025 mm thick – ten times thinner than those in a typical production electric motor. That puts them at, or even below, the thickness of a human hair.

• Material: amorphous steel instead of conventional electrical steel
• Lamination thickness: 0.025 mm rather than approximately 0.25 mm
• Aim: halve magnetic and electrical losses in the stator
• Laboratory result: 98.2% efficiency

These exceptionally thin sheets restrict the formation of eddy currents, unwanted electrical circuits within the metal itself. Such currents turn part of the electrical energy into heat, leaving less available for propulsion. Thinner laminations provide less scope for these effects to develop.

How large the efficiency gain really is

Depending on their operating point, modern electric motors already achieve efficiencies of between 93 and 97%. The obvious question for many readers is therefore whether 98.2% makes any difference in daily use.

The honest answer is that the consumption display would show only a difference of a few percentage points. Horse itself calculates that a complete hybrid system would require around 1% less energy. That may sound modest, but it has two dimensions:

Parameter	Typical electric motor	Amorfo motor (Horse)
Efficiency (laboratory, peak)	93–97%	98.2%
Internal losses	100% (reference)	approx. 50% of the reference
System effect in a hybrid	Baseline	~1% lower energy consumption

At vehicle level, additional losses always come into play, including those from the inverter, gearbox, battery chemistry and tyres. The motor is only one part of the system. Its peak-efficiency point also occurs within a narrow operating window that is not maintained constantly in everyday traffic. As a result, the laboratory figure of 98.2% quickly becomes a real-world consumption reduction of 1%.

One per cent lower energy consumption may seem insignificant for a single car – but across millions of vehicles over many years, it creates a clearly measurable effect.

Why manufacturers pursue seemingly small percentage gains

European CO₂ limits are exerting pressure, while efficiency ratings in China influence subsidies and fleet assessments. Every percentage point saved reduces manufacturers' penalty payments, improves ratings and gives them room to offer larger, heavier body styles without immediately moving into the next CO₂ band.

For fleet operators such as car-sharing and delivery services, a 1% reduction in consumption can save several hundred pounds in energy costs over a vehicle's lifetime. The benefit becomes more significant when similar gains are combined across every component: a more efficient motor, lower-loss power electronics, optimised thermal management and low-rolling-resistance tyres.

Between laboratory and road: unanswered questions about the Amorfo motor

For now, the Amorfo remains a power unit tested on a bench. Horse has published output and efficiency figures, but has not named a specific production model. Nor is there a date for when the motor will first be installed in a Renault or a Geely-affiliated vehicle.

Real-world use introduces further factors that cannot be fully recreated in a laboratory:

• Temperature changes ranging from severe sub-zero conditions to heatwaves
• Mechanical vibrations, potholes and long-term loading
• Manufacturing tolerances for extremely thin laminations
• Ageing of the amorphous steel and insulation

A particularly important question is how production of these stators can be organised at high volumes. Amorphous steel is demanding to process. The laminations must be stacked and insulated with precision. Even minor imperfections could partly erase the efficiency advantage.

What Amorfo could mean for hybrid and electric cars

In an ideal scenario, the motor could support three different approaches, depending on the vehicle concept:

• The same performance with a slightly smaller battery, reducing costs.
• An unchanged battery size, delivering greater range or lower consumption.
• More performance with the same consumption, for example in heavy SUVs or vans.

Renault could, for instance, use Amorfo in future E-Tech hybrids to reduce WLTP-cycle consumption by a few tenths of a litre. For Geely brands such as Volvo or Lynk & Co, an especially efficient electric motor could be a selling point in markets where tax is closely linked to CO₂ values.

How to picture the everyday effect

Consider a plug-in hybrid that uses 18 kWh per 100 kilometres in electric mode. If the Amorfo motor makes the powertrain roughly 1% more efficient, consumption would theoretically fall to about 17.8 kWh. A driver would scarcely notice this directly on the display. Across 150,000 kilometres, however, the difference adds up to around 300 kWh.

At an electricity price of 35 cents per kWh, that one vehicle would save about €100. That appears limited, but if a group sells one million such vehicles, customers' energy-cost savings would run into hundreds of millions, while several terawatt-hours of electricity would no longer be needed.

Risks and limits of the new technology

Every new material technology carries risks. Amorphous steel costs more than conventional electrical steel. If the material price rises sharply, the financial case for the efficiency gain can quickly weaken. Repairability and recyclability are also open questions, as extremely thin and specially alloyed sheets create new challenges for dismantling businesses.

There is another consideration: a motor with such low losses generates less heat internally. While that sounds positive, it requires highly precise thermal management from engineers. In low temperatures, the motor itself and, where necessary, the battery must be brought into an efficient temperature window more quickly. Only then can the technology realise its potential.

Why efficiency is still worth watching

The Amorfo motor represents a new phase in competition over powertrain technology. After range, charging power and battery capacity dominated attention for years, the more prosaic subject of efficiency is returning to the foreground. Particularly in markets where incentives are stagnating, clearly better efficiency may decide the choice between two similar models.

For private buyers, it will increasingly be worthwhile to examine technical specifications beyond PS figures and battery capacity. How efficiently a car converts 1 kWh of electricity into actual kilometres will ultimately determine running costs, residual value and its CO₂ footprint. Amorfo puts that issue on the agenda with an impressive figure – and forces other manufacturers to reconsider how they make motors.