Techno-economic and environmental assessment of hybrid and electric retrofits for heavy-duty trucks

Decarbonising heavy-duty vehicle (HDV) fleets is challenging due to high energy demands, long service lives, and slow adoption of electric alternatives. While passenger vehicle electrification progresses, legacy diesel HDVs lag behind. Retrofitting existing HDVs with hybrid or electric powertrains presents a cost-effective path to greenhouse gas (GHG) reductions. However, existing studies rely on simulations and overlook real-world complexities. This study addresses these gaps by providing a techno-economic and environmental assessment of three retrofit options—parallel hybrid, series hybrid, and fully electric—applied to two truck platforms under urban and regional duty cycles. Using GPS-based drive cycle data, it evaluates energy use, regenerative braking, fuel savings, GHG reductions, and return on investment (ROI). Results show the series hybrid offers the highest ROI with 98% GHG reduction in urban use. The analysis identifies key trade-offs in cost, storage sizing, and performance, offering actionable insights for fleet operators and policymakers aiming for economically sustainable transitions.