COMPARISON OF ELECTRIC VEHICLE ENERGY CONSUMPTION MODELS AND INTERNAL COMBUSTION ENGINE VEHICLE FUEL CONSUMPTION STANDARDS IN MOUNTAINOUS CONDITIONS (CASE STUDY: KULOB – SHOHON ROUTE)

Abstract

This paper presents a comparative analysis between the fuel consumption standards for internal combustion engine vehicles currently effective in the Republic of Tajikistan and a previously proposed physical-mathematical model for electric vehicle energy consumption with regenerative braking. The evaluation was conducted on a challenging mountainous route, Kulyab – Shamsiddin Shohin – Shohon (64 km, mountain pass at 1980 m). For a gasoline vehicle weighing 2100 kg (base rate of 10 L/100 km), the elevation surcharge increases consumption by 9.8% (from 6.40 to 7.03 L). For an electric vehicle of equivalent mass, given a baseline flat-terrain consumption of 7.41 kWh, uphill driving increases energy consumption to 9.09 kWh (+22.7%), whereas downhill driving with regenerative braking reduces it to 5.93 kWh (−20.0%). The directional disparity reaches 3.2 kWh, while the average round-trip consumption (7.51 kWh) exceeds the baseline horizontal value by only 1.4%. It is shown that existing standardized methodologies applying equal elevation surcharges in both directions fail to account for the recovery of gravitational potential energy via regenerative braking. These findings justify the necessity of revising operational performance assessment methodologies for electrified transport. Under current electricity and fuel tariffs in Tajikistan, the difference in specific operating costs along this route reaches 22–26 times in favor of the electric vehicle.