Plug-in hybrid electric vehicles (PHEVs) are fast becoming a central part of fleet decarbonisation strategies. With flexible powertrains and real-world electric driving ranges that now stretch to 100km, they offer Fleet Managers a practical bridge between internal combustion and full battery-electric vehicles. But there’s one important caveat: they only deliver emissions reductions when they’re charged regularly and used correctly.
This is where effective fleet monitoring becomes critical.
PHEV Performance Depends on Charging Behaviour
Unlike conventional hybrids, PHEVs rely on their battery being actively charged to unlock their full emissions and fuel-saving potential. If drivers skip the charging step and run the vehicle in petrol mode, the fuel economy can actually be worse than a standard ICE vehicle, due to the added weight of the battery and electric motors.
More importantly, the uncharged PHEV produces more CO₂ emissions than expected. For organisations focused on reducing emissions or meeting ESG goals, this can cause reporting discrepancies and damage credibility.
Put simply, a PHEV that isn’t plugged in becomes a liability—not a solution.
IPWEA PVMM: Maturity Matters
The Institute of Public Works Engineering Australasia (IPWEA) outlines a clear pathway for Fleet Managers through its Plant and Vehicle Management Manual (PVMM). The framework categorises fleet management maturity into Core, Intermediate, and Advanced levels.
At the Advanced level, Fleet Managers have detailed visibility of costs, utilisation, and asset performance—often down to the kilometre or hour. They know what each vehicle is doing, when, and why. This is the level where monitoring PHEV charging rates should be standard practice.
If you’re unsure how often your PHEVs are charging, or you can’t compare electric versus petrol operation, it’s likely your fleet is operating at the Core or Basic level of maturity. And that’s okay—everyone has to start somewhere. But introducing PHEVs without the systems to monitor and manage them raises risks.
Data-Driven Management of Emissions
PHEVs complicate the emissions story. Their real-world performance is variable and dependent on behaviour. This makes them different from ICE vehicles (predictable emissions) or BEVs (zero tailpipe emissions). To manage this complexity, Fleet Managers need data—and lots of it.
Here’s what should be tracked:
- Charging frequency and energy consumed
- Distance driven in electric vs petrol mode
- Fuel economy and emissions by driver or trip
- Charging locations (home, depot, public)
- Charger availability and downtime
Telematics and software platforms can already provide this information. Using them helps identify gaps in driver education, infrastructure, or operational planning that may be limiting the benefits of PHEVs.
The Opportunity for Improvement
Monitoring PHEV charging behaviour isn’t just about compliance—it’s a path to better fleet outcomes. It helps:
- Maximise return on investment
- Lower fuel costs
- Reduce emissions
- Identify underutilised assets
- Plan future EV infrastructure more effectively
And most importantly, it moves your organisation along the fleet maturity curve—toward data-driven, evidence-based decisions that withstand external scrutiny.
For Fleet Managers, the message is clear: If you’re not measuring charging rates, you’re not managing PHEVs.
