How Euro 6e-bis Testing Changes in 2025 will Impact PHEVs
In 2025, the UK will implement stricter emissions testing for plug-in hybrid electric vehicles (PHEVs) under the Euro 6e-bis standard.
This new testing protocol aims to provide a more accurate representation of real-world CO2 emissions for PHEVs. These changes are part of broader efforts to ensure that vehicle emissions standards more accurately reflect real-world driving conditions, thereby promoting environmental sustainability.
This change aims to provide more accurate CO₂ emissions data, which could significantly impact taxation, especially for company car drivers.
What exactly is Euro 6e-bis?
Euro 6e-bis is an enhancement of the Euro 6 emissions standard, specifically targeting plug-in hybrid electric vehicles (PHEVs).
What are Euro 6 Emissions, the evolution of Euro Emission standards
1. Euro 1 (1992) - First mandatory emissions standard for passenger cars. Required catalytic converters and unleaded petrol. Limits: CO: 2.72 g/km, HC + NOx: 0.97 g/km and PM (diesel): 0.14 g/km
2. Euro 2 (1996) -Further reduced NOx and CO emissions. Introduced separate limits for petrol and diesel engines. Limits (petrol/diesel): CO: 2.2 / 1.0 g/km, HC + NOx: 0.5 / 0.7 g/km and PM (diesel): 0.08 g/km
3. Euro 3 (2000) -Eliminated HC + NOx combined limit and set separate limits for NOx. Limits: CO: 2.3 / 0.64 g/km, HC: 0.2 g/km, NOx: 0.15 g/km and PM (diesel): 0.05 g/km
4. Euro 4 (2005) -Significant reduction in diesel NOx and PM emissions. Popularized diesel particulate filters (DPF). Limits: CO: 1.0 / 0.5 g/km, HC: 0.1 g/km, NOx: 0.08 g/km and PM (diesel): 0.025 g/km
5. Euro 5 (2009) -Further NOx and PM reductions for diesel vehicles. Mandated DPFs for diesel vehicles. Limits: NOx (diesel): 0.18 g/km and PM (diesel): 0.005 g/km
6. Euro 6 (2014) -Major NOx cuts for diesel vehicles. Encouraged Selective Catalytic Reduction (SCR) and AdBlue technology. Introduced Real Driving Emissions (RDE) testing. Limits: NOx (diesel): 0.08 g/km and PM: 0.0045 g/km
7. Euro 6d-Temp (2019) & Euro 6d (2021) -Strengthened RDE tests. Lowered NOx compliance thresholds. Measured emissions using Portable Emission Measurement Systems (PEMS).
8. Euro 6e-bis (01/01/2025) and Euro 7 (Coming 2025) -Will introduce stricter NOx, PM, and brake dust limits. Focus on electric and hybrid vehicle regulations. Stricter on-board diagnostics (OBD) monitoring.
Key Changes under Euro 6e-bis
- Extended Testing Distance: The simulated distance for emissions testing will increase from 800 km (497 miles) to 2,200 km (1,367 miles), offering a more comprehensive assessment of a PHEV's performance over longer drives.
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Revised Utility Factor (UF): The UF, which determines the proportion of driving in electric-only mode, will be adjusted to reflect more realistic usage patterns.
This adjustment is expected to result in HIGHER official CO₂ emission values for many PHEVs.
Implications for Fleet Operators and Company Car Drivers
For company car drivers, these changes could lead to higher Benefit-in-Kind (BiK) tax rates.
To illustrate how the revised UF curves affect the official CO2 emission values of PHEVs, the International Council on Clean Transport (ICCT) analysed the effect on a BMW X1 xDrive25e PHEV. The vehicle can drive a distance in charge depleting operation of about 70km (43 miles). Using the current UF curve, this results in an official CO2 emission value of approximately 45g/km.
When applying the Euro 6e-bis UF, the CO2 emission value of the X1 will almost double to 96g/km.
Consequently, the BiK rate for the X1 would increase from 8% to 24% and likely the car will no longer feature on a company's car policy choice list. Thus, resulting in a reduced choice of PHEV vehicles for drivers.
Higher BIK rates means not only increased driver taxation but also Company Employers National Insurance Tax (NIC) increases. Cconsidering the main rate of employers’ National Insurance contributions in the UK will increase from 13.8% to 15% from April 2025.
When will this Apply?
It's important to note that these standards will apply to all new PHEV models launched from January 1, 2025.
For existing models from December 31, 2025.
Current PHEV company car drivers will not be affected unless they purchase/lease a new vehicle after these dates so there is an incentive to take a PHEV vehicle before 31/12/2025.
Looking Ahead...
In 2027 the Euro 6 emissions standard is due to be changed again, to Euro 6e-bis-FCM, which will increase the UF distance to 4,260 km (2,647 miles), which will further inflate the official CO2 emission scores of PHEVs.
In the above example, this would mean the BMW X1 CO2 emission value will likely increase again to 122 g/km under Euro 6e-bis-FCM regulations.