DOI: 10.18245/ijaet.1980022 ISSN: 2146-9067

Economic trade-off of regenerative braking in hybrid vehicles: recovered-energy value versus accelerated battery degradation, with a worked case study for Turkish operating conditions

Kadir Aydın
Show PDF Cite
In a hybrid electric vehicle (HEV), regenerative braking converts part of the vehicle’s kinetic energy into electricity that is stored and later reused, displacing fuel. This recovered energy is effectively free, because its only alternative is dissipation as heat in the friction brakes; however, the extra charge throughput and the high charge-rate (C-rate) pulses associated with braking accelerate battery aging, which carries a replacement cost. This paper presents a transparent, parameterized methodology that evaluates the net economic value of regenerative braking as the difference between two opposing cash flows: the monetized value of the recovered energy and the levelized cost of the accelerated battery degradation it causes. The benefit branch is built from the powertrain round-trip efficiency chain and an equivalent-fuel valuation; the cost branch from a power-law capacity-fade model and a levelized degradation cost, cdeg = cpack/NEFC. The two branches are unified in marginal-value and net-present-value (NPV) terms and examined with tornado and Monte-Carlo analyses. A case study is developed for a representative C-segment full hybrid under Turkish conditions at a gasoline price of 1.40 USD/L. The braking-energy input is validated against urban and extra-urban driving-cycle simulations that bracket the adopted value (0.028-0.058 kWh/km). For 15,000 km/yr the model recovers about 233 kWh/yr of usable traction energy, saving roughly 87 L of gasoline (≈ 121 USD) per year against a degradation cost of only ≈ 11 USD/yr, a benefit-to-cost ratio near 11:1. For a realistic 15-year service life (≈ Turkish fleet average) the discounted lifetime NPV is ≈ 840 USD per vehicle; longer horizons add little because of discounting. A Monte-Carlo analysis returns a positive NPV in essentially 100% of cases. The net value is robustly positive, narrowing only to extreme C-rates, high cell temperatures, or with expensive chemistries.

More from our Archive