While adoption of electric mobility continues to accelerate, full electrification cannot and will not happen overnight. Barriers in cost, infrastructure and differing global usage patterns mean that internal combusting engines will continue to play a role for the foreseeable future.
Plug-in Hybrid Electric Vehicles (PHEVs) are a key technology in bridging this gap. By combining electric propulsion with an internal combustion engine, PHEVs offer zero tailpipe emissions for short journeys while retaining the flexibility of conventional refuelling for longer distances.
For a lot of people and markets, that balance matters.
A PHEV combines an electric motor, a rechargeable battery, and a petrol or diesel engine.
Like a Battery Electric Vehicle (BEV), it can drive on electric power alone - typically for 20-60 miles depending on battery size. Unlike a conventional hybrid (HEV), it must be plugged in to fully recharge its larger battery.
When the battery charge drops below a set level, the combustion engine engages. In most PHEV architectures, the engine can directly assist in driving the wheels, unlike a Range-Extended Electric Vehicle (REEV), where it’s just the engine that generates electricity.
Read more about vehicle types with what is a REEV?
At first glance, a PHEV behaves much like a BEV in daily use. When fully charged, it prioritizes electric propulsion, delivering silent, zero-emission driving for urban and short-distance journeys. Charging is typically carried out via a home wallbox, public charging infrastructure, or, less commonly, a standard domestic socket.
Because the battery is larger than that of a traditional hybrid, a PHEV can complete most daily commutes without engaging the combustion engine. Once the battery depletes to a certain level, the internal combustion engine activates to help propel the vehicle.
A PHEV’s engine forms part of a blended propulsion system. This dual-mode operation provides flexibility and efficiency: drivers use electric-only mode for short trips, or engine-supported mode for longer-range, high-speed driving.
However, efficiency ultimately depends on user behaviour. If a PHEV is not regularly charged, it effectively carries additional battery weight without fully utilizing its electric capability, reducing its overall efficiency advantage.
A PHEV can complete most daily commutes without engaging the combustion engine
Read more about vehicle types with what is a HEV?
PHEVs offer flexibility in markets where charging infrastructure, geography, or driving patterns make full BEV adoption challenging.
They allow for electric driving for short journeys, fuel-powered range for longer distances, and lower-risk transition into electrified mobility.
However, their environmental and efficiency advantages depend on user behaviour. When regularly charged and used primarily in electric mode, they can significantly reduce emissions. From a lifecycle perspective, the combination of smaller battery size and reduced fuel consumption can also deliver overall efficiency gains compared with conventional internal combustion vehicles.
Read more about how tighter PHEV utility factor requirements will harm the auto industry.
PHEVs sit between conventional hybrids and fully electric vehicles - while they play an important role in the broader shift towards decarbonized mobility, they have secured their place as a long-term staple of the global vehicle park.
Rather than serving only as a transitional technology, PHEVs provide a scalable and practical solution for many markets where full electrification faces economic, infrastructure, or usage challenges.
At Horse Powertrain we understand that each country, region and town has different infrastructure barriers, that’s why we provide multiple powertrain options that suit every scenario.
Find out more about our solutions here: spotlight solutions.