*2.3. Road Freight Transport in Japan and Scenarios for Deep Decarbonization*

Japan was selected as the case study, considering public acceptance of EDVs in the passenger LDV fleet; as well as being home to major OEMs. Historical data for road freight vehicle fleet stock, energy consumption and CO2 emissions for the years 2012 to 2016 were used to calibrate the model. Due to the long time scales involved in vehicle stock turnover, the time horizon was set between 2012 and 2050.

In the year 2012, road freight vehicle stock totaled 14.8 million vehicles; with normal, compact and mini-sized vehicles accounting for 15.3%, 24.8% and 60.0%, respectively [67]. The road freight vehicle stock distribution by vintage was constructed using data from AIRIA [68]. Data correspond to normal and compact vehicles. Due to data availability constraints, the same vehicle stock distribution was assumed for mini-sized road freight vehicles. Since available data only cover 20 vintages, in contrast with the 30 vintages considered in the model, the aggregated data for vintages 20 or older were redistributed by extrapolating the tendency for vintages newer than 20 years, guarantying that the sum of all vintages totaled 100%. The resulting vehicle stock distribution is shown in Figure 5.

**Figure 5.** Vehicle stock distribution.

Annual sales for road freight vehicles in 2012 totaled 0.79 million vehicles; with normal, compact and mini-sized vehicles accounting for 17.4%, 28.9% and 53.7%, respectively [67]. Deployment of EDVs in road freight vehicles is still at an early stage, with 25 BEVs and 12204 HEVs in 2012 [69]. For matter of simplicity, it was considered that 2012 road freight vehicle stock and new vehicle sales were made only of ICEVs.

A scenario-based approach was used to assess the role of powertrain electrification in the decarbonization of the road freight vehicle fleet. Four scenarios, the Base scenario and three alternative scenarios for powertrain electrification were considered. All scenarios were defined in terms of the share of the powertrains in the 2050 new vehicle sales, as shown in Table 2.


**Table 2.** Dominant powertrain in the 2050 new vehicle sales in each scenario.

 Partial dominance; total dominance.

The Base scenario represents the continuation of current trends, with HEVs and ICEVs dominating 2050 new vehicle sales, 38.3% and 55.1%; while BEVs and FCEVs do not achieve significant deployment, each of them accounting for 3.3% of the new vehicle sales [46]. New vehicle sales are shown in Figure 6. The growth trends for the new vehicle sales for each vehicle size class were adjusted using data from the Japan Ministry of Environment (MOE) [65] for future sales forecast, and from the Japanese Automobile Manufacturers Association (JAMA) [70] for historical sales. It was assumed that new vehicle sales do not vary across scenarios.

**Figure 6.** New vehicle sales.

The HBB, HFF and FBB scenarios correspond to alternative scenarios where powertrain electrification is targeted by 2050. These alternative scenarios were built using a 'silver bullet' approach, where only one powertrain technology dominates each vehicle size class. Since normal road freight vehicles are usually used to travel the longest distances, corresponding to trips between cities often located in different prefectures, and are the heaviest, using BEV in this vehicle size class would require large batteries to complete each trip without stopping, or more frequent stops for battery charging; both of which increase the cost. Therefore, only HEVs or FCEVs were considered as candidates for powertrain electrification in normal vehicles. In compact and mini-sized vehicles, used typically for travels within cities that require shorter trips, powertrain electrification using BEVs

and FCEVs was assessed. The HBB and HFF scenarios focus on mild decarbonization in normal vehicles using HEVs and deep decarbonization in compact and mini-sized vehicles using BEVs or FCEVs. The FBB scenario focuses on deep decarbonization across all vehicle size classes using FCEVs in normal vehicles and BEVs in compact and mini-sized vehicles.

Market shares for EDVs in the alternative scenarios evolve as indicated in Figure 7. These technology diffusion curves were estimated following the methods described in [71]. It was assumed that 2020 is the initial year for HEV diffusion; while 2025 is the initial year for BEV and FCEV diffusion. EDV diffusion was considered symmetrical, with a technology diffusion span of 30 years [72].

**Figure 7.** Technology diffusion profiles.

In order to compare the merit of each scenario in the decarbonization of the road freight vehicle fleet, a score analysis was performed. The performance of each scenario in 2050 was assessed in terms of the road freight vehicle fleet TTW energy consumption, WTW CO2 emissions and RCO. The scores were estimated following the methods developed in [73] using Equation (5):

$$Score = \frac{Maximum - Data\_{\text{selected scenario}}}{Maximum - minimum} 100\tag{5}$$
