Division Formula 1

United Kingdom

C_{{CO}_{2}} = S_{IR} \times {UF}_{IR} \times η_{SS} \times \frac{\bar{{mP}_{P}}}{S_{IR_STC}} \times SCC \times \frac{V_{Pe}}{η_{A}} \times \frac{CF}{M} \times cosΦ - {ΔCO}_{2m}

Where:

C_{{CO}_{2}}

CO₂ savings [g CO₂/km]

S_IR

Yearly European mean solar irradiation [W/m²], which is 120 W/m²

UF_IR

Usage factor (shading effect) [-], which is 0,51

η_SS

Efficiency of the photovoltaic system [%], which is 76 %

\bar{{mP}_{P}}

Measured average PV roof peak power output [W]

S_{IR_STC}

Global irradiation at Standard Test Conditions (STC) [W/m²], which is 1 000 W/m²

SCC

Solar correction coefficient [-] as defined in Table 1. Total available storage capacity of the battery system or the SCC value is to be supplied by the vehicle manufacturer.

Table 1

Solar correction coefficient

The total storage capacity includes a mean usable storage capacity of the starter battery of 10 Ah (12 V). All values refer to a mean annual solar radiation of 120 W/m², a shading share of 0,49 and a mean vehicle driving time of 1 hour per day at 750 W electric power requirement.
Total available storage capacity of (12 V) battery system/average PV roof peak power output [Ah/W]^f1	0,10	0,20	0,30	0,40	0,50	0,60	> 0,666
Solar correction coefficient (SCC)	0,481	0,656	0,784	0,873	0,934	0,977	1

V_Pe

Consumption of effective power [l/kWh] as defined in Table 2

Table 2

Consumption of effective power

Type of engine	Consumption of effective power (V_Pe)[l/kWh]
Petrol	0,264
Petrol Turbo	0,280
Diesel	0,220

η_A

Efficiency of the alternator [%], which is 67 %;

Conversion factor (l/100km) — (g CO₂/km) [gCO₂/l] as defined in Table 3

Table 3

Fuel conversion factor

Type of fuel	Conversion factor (l/100 km) — (g CO₂/km) (CF)[gCO₂/l]
Petrol	2 330
Diesel	2 640

Mean annual mileage [km/year] as defined in Table 4

Table 4

Mean annual mileage for M₁ vehicles

Type of fuel	Mean annual mileage (M) [km/year]
Petrol	12 700
Diesel	17 000

Lengthwise inclination of the solar panel [°]. This value is to be supplied by the vehicle manufacturer

ΔCO_2m

CO₂ correction coefficient due to the extra mass of the solar roof and, where applicable, the additional battery and other appliances needed specifically for the conversion of the solar energy into electricity and its storage [g CO₂/km] as defined in Table 5.

Table 5

CO₂ correction coefficient due to the extra mass

Type pf fuel	CO₂ correction coefficient due to the extra mass (ΔCO_2m)[g CO₂/km]
Petrol	0,0277 · Δm
Diesel	0,0383 · Δm

In Table 5 Δm is the extra mass due to the installation of the photovoltaic system, composed by the PV roof and, where applicable, the additional battery and other appliances needed specifically for the conversion of the solar energy into electricity and its storage.

In particular, Δm is the positive difference between the mass of the photovoltaic system mass and the mass of a standard steel roof. The mass of a standard steel roof is assumed equal to 12 kg. In case the weight of the solar system is lower than 12 kg, no correction for the change in mass has to be made.

Annotations

Footnotes

f1: The total storage capacity includes a mean usable storage capacity of the starter battery of 10 Ah (12 V). All values refer to a mean annual solar radiation of 120 W/m², a shading share of 0,49 and a mean vehicle driving time of 1 hour per day at 750 W electric power requirement.

Notes on Division 4

Marginal citations

M1: ... [Editorial note: Annex para. 4 footnote omitted (31.12.2020) by virtue of The Road Vehicle Carbon Dioxide Emission Performance Standards (Cars and Vans) (Amendment) (EU Exit) Regulations 2019 (S.I. 2019/550), regs. 1, 25(3); 2020 c. 1, Sch. 5 para. 1(1)]