Case study: Electric heavy-duty trucks & bus electrification — a city or utility pilot and the results so far

Shenzhen, China became the first city in the world to electrify its entire public bus fleet of 16,359 vehicles in December 2017, and by mid-2025 had accumulated over 4.8 billion electric bus kilometers in revenue service. The city's cumulative operational data, spanning more than seven years, shows a 72% reduction in per-kilometer CO2 emissions compared to the diesel fleet it replaced, a 64% decrease in per-kilometer maintenance costs, and annual fuel savings exceeding 1.6 billion yuan ($220 million). Shenzhen's experience, alongside pilots in Bogota, Los Angeles, and Jakarta, offers executives the most comprehensive evidence base available for evaluating heavy-duty electric vehicle deployments at municipal scale.

Why It Matters

Heavy-duty vehicles, including transit buses, freight trucks, and refuse collection vehicles, represent only 4% of vehicles on the road globally but account for roughly 40% of road transport CO2 emissions and a disproportionate share of urban nitrogen oxide (NOx) and particulate matter (PM2.5) pollution (International Council on Clean Transportation, 2025). Cities and transit agencies sit at the center of decarbonization pressure because they operate large captive fleets with predictable routes, making them ideal candidates for electrification.

The Asia-Pacific region leads global e-bus adoption by a wide margin. China alone operates over 770,000 electric buses as of early 2026, representing more than 90% of the global e-bus fleet (Bloomberg NEF, 2026). India's FAME II and subsequent PM-eBus Sewa programs have committed to deploying 10,000 electric buses across 169 cities. Southeast Asian markets including Thailand, Indonesia, and Vietnam are launching pilot programs with varying levels of government subsidy and private investment. For executives evaluating fleet transitions, understanding what has worked and what has not in these early large-scale deployments is essential for avoiding costly missteps.

The financial case is strengthening rapidly. Battery pack prices for commercial vehicles declined to $115 per kWh in 2025, down from $153 per kWh in 2022 (Bloomberg NEF, 2026). Total cost of ownership (TCO) parity between electric and diesel buses has now been reached in markets with electricity prices below $0.12 per kWh, which includes most of China, India, and parts of Southeast Asia.

Key Concepts

Depot charging vs. opportunity charging: Depot charging installs slow chargers (40 to 80 kW) at bus depots for overnight replenishment. Opportunity charging uses high-power chargers (300 to 600 kW) at route endpoints or intermediate stops for rapid top-ups during service. Shenzhen uses depot charging almost exclusively, while Bogota's TransMilenio pilot employs opportunity charging at terminal stations.

Battery right-sizing: Matching battery capacity to route requirements avoids carrying unnecessary weight that reduces passenger capacity and increases energy consumption. Shenzhen's BYD K9 buses carry 324 kWh batteries for routes averaging 250 km per day, while shorter urban routes in Jakarta use 200 kWh packs.

Grid impact management: Large bus depots can draw 5 to 15 MW when charging simultaneously. Managed charging, which staggers charge start times based on departure schedules and electricity pricing, can reduce peak demand by 30 to 50% without affecting operational readiness.

Vehicle-to-grid (V2G) potential: Electric buses parked during off-peak hours represent distributed energy storage assets. Pilot programs in Shenzhen and Seoul are testing bidirectional charging to provide grid services during demand peaks.

What's Working

Shenzhen: Full Fleet Electrification at Scale

Shenzhen's transition began in 2011 with a pilot of 200 BYD K9 electric buses and reached full fleet electrification by the end of 2017. The city operates three major bus companies: Shenzhen Bus Group, Eastern Bus, and Western Bus, which collectively run 16,359 electric buses across 980 routes covering a service area of 1,997 square kilometers.

Operational data through mid-2025 shows energy consumption averaging 1.15 kWh per km, a 28% improvement from the 1.6 kWh per km measured during the initial pilot phase. This improvement reflects driver training programs, route optimization, and battery management system software updates. Maintenance costs declined to 0.32 yuan per km from 0.89 yuan per km for diesel equivalents, driven primarily by elimination of engine, transmission, and exhaust aftertreatment servicing (Shenzhen Transport Commission, 2025).

The charging infrastructure comprises 510 depot charging stations with a combined 26,000 charging points. Average nightly charging time is 3.5 to 4 hours at 60 kW per charger. The city invested approximately 8.9 billion yuan ($1.25 billion) in the fleet transition between 2011 and 2017, with national and municipal subsidies covering roughly 60% of the incremental cost above diesel bus procurement.

Bogota: Opportunity Charging for BRT

Bogota launched Latin America's largest electric bus deployment in 2020, placing 406 BYD and Zhongtong electric buses into TransMilenio bus rapid transit (BRT) service. The fleet expanded to 1,485 electric buses by early 2026, representing approximately 20% of the city's total transit fleet.

The TransMilenio system operates routes averaging 30 to 45 km with high daily utilization of 280 to 320 km per bus. To accommodate this intensive duty cycle, the system uses 350 kW opportunity chargers at terminal stations, delivering 80 to 100 kWh in 15 to 20 minute layover periods. The hybrid charging strategy, combining overnight depot charging with daytime opportunity top-ups, has achieved fleet availability rates of 94%, comparable to the diesel fleet's 95% availability (TransMilenio S.A., 2025).

Energy cost savings have been significant. Colombia's electricity rates for large commercial consumers average $0.08 per kWh, and electric bus energy costs of approximately $0.12 per km compare favorably to diesel costs of $0.38 per km. The fleet is saving the city an estimated $28 million per year in fuel costs alone.

Jakarta: Public-Private Partnership Model

Jakarta's TransJakarta BRT system began electric bus trials in 2022 with 30 vehicles and expanded to 200 electric buses by 2025. The deployment uses a lease model in which PT TransJakarta procures vehicles through a gross-cost contract with private operators, who are responsible for vehicle maintenance and charging infrastructure. This structure shifts technology risk to operators while allowing the transit authority to set service standards and route assignments.

The pilot has demonstrated a 35% reduction in per-passenger-km emissions compared to the compressed natural gas (CNG) buses it replaced, though challenges with charging infrastructure reliability have limited fleet availability to 87%, below the 92% target (PT TransJakarta, 2025). High ambient temperatures (averaging 32 degrees Celsius) and humidity levels have accelerated battery thermal management system cycling, with energy consumption approximately 12% higher than manufacturer specifications developed for temperate climate conditions.

What's Not Working

Battery degradation in tropical climates: High ambient temperatures accelerate lithium-ion battery aging. Shenzhen's fleet data shows capacity retention of 88% after five years in subtropical conditions, while Jakarta reports capacity retention of only 82% after three years in equatorial conditions. Battery thermal management systems designed for temperate climates require recalibration and additional cooling capacity for tropical deployments, adding 5 to 8% to vehicle costs.

Charging infrastructure bottlenecks: Shenzhen's early experience included significant grid congestion at depots, with transformer capacity limits forcing some buses to queue for available chargers. Approximately 8% of the fleet could not complete a full charge cycle before morning departure during peak demand periods in 2018 and 2019. The city addressed this through $180 million in grid upgrades and implementation of smart charging management systems.

Workforce transition gaps: Shenzhen retrained approximately 2,400 diesel mechanics for electric vehicle maintenance, but the 18-month training cycle created a period during which specialized EV diagnostics were performed by manufacturer technicians at premium rates. Bogota and Jakarta are experiencing similar workforce readiness challenges, with maintenance labor costs 20 to 30% higher than projected during the first two years of deployment.

Supply chain concentration risk: Over 90% of Asia-Pacific e-bus deployments use vehicles from Chinese manufacturers (BYD, Yutong, Zhongtong, and Higer). This concentration creates vulnerability to trade policy changes, component shortages, and limited leverage in warranty negotiations. Indian agencies deploying Tata Motors and Olectra-BYD joint venture vehicles are partially diversifying, but still depend heavily on Chinese battery cell supply.

Key Players

Established companies: BYD (world's largest electric bus manufacturer with over 70,000 units deployed globally), Yutong Bus (China's leading transit bus producer with 60% domestic market share in e-buses), Tata Motors (India's primary e-bus supplier under FAME II and PM-eBus Sewa), Volvo Buses (supplying electric articulated buses to Bogota and European markets), and Mercedes-Benz (eCitaro platform deployed in Singapore and Australian pilots)

Startups and growth-stage: Arrival (UK-based, microfactory model for purpose-built electric buses), Switch Mobility (Ashok Leyland subsidiary scaling electric bus production in India), Zenobe Energy (UK fleet-as-a-service provider expanding into Asia-Pacific markets), and EKA Mobility (Indian electric commercial vehicle manufacturer)

Investors and financiers: Asian Development Bank (ADB, financing e-bus programs across South and Southeast Asia), World Bank (providing technical assistance and concessional lending for urban transit electrification), Green Climate Fund (co-financing e-bus deployments in developing country cities), and HSBC (structuring green bonds for transit electrification in India and Indonesia)

KPI Benchmarks

Metric	Shenzhen	Bogota	Jakarta	Target Range
Energy consumption (kWh/km)	1.15	1.28	1.42	1.0 - 1.4
Fleet availability (%)	96	94	87	>93
Maintenance cost reduction vs. diesel (%)	64	48	35	40 - 65
Battery capacity retention at Year 3 (%)	93	91	82	>88
CO2 reduction vs. diesel (%)	72	65	35 (vs. CNG)	60 - 80 (vs. diesel)
Charging infrastructure uptime (%)	97	94	88	>95

Action Checklist

• Conduct route-level energy simulation using GPS and ridership data to right-size battery capacity, avoiding over-specification that inflates vehicle cost and reduces passenger capacity
• Engage the local electricity utility 12 to 18 months before deployment to assess transformer capacity at depot locations and plan grid upgrades
• Implement managed charging software from day one, staggering charge start times to reduce peak demand by 30 to 50% and lower demand charges
• Negotiate battery warranty terms with clear capacity retention thresholds (minimum 80% at 8 years) and degradation measurement protocols using standardized testing procedures
• Launch mechanic retraining programs at least 12 months before fleet delivery, covering high-voltage safety, battery diagnostics, and electric drivetrain maintenance
• Establish real-time fleet monitoring dashboards tracking energy consumption, state of charge, battery temperature, and charging completion status
• For tropical deployments, specify enhanced thermal management systems and request battery performance validation data at sustained ambient temperatures above 35 degrees Celsius
• Structure procurement contracts to include performance guarantees for fleet availability (>93%) with financial penalties for sustained underperformance

FAQ

Q: What is the total cost of ownership comparison between electric and diesel transit buses in Asia-Pacific markets? A: At 2025 battery prices ($115/kWh) and typical Asia-Pacific electricity rates ($0.06 to $0.12/kWh), electric buses achieve TCO parity with diesel at approximately 60,000 km per year of utilization over a 12-year service life. Shenzhen's data shows a 12-year TCO of approximately 1.5 million yuan ($210,000) per bus for electric versus 1.9 million yuan ($267,000) for diesel, a 21% advantage. Markets with higher diesel costs or lower electricity rates see even stronger economics. The breakeven utilization threshold drops to approximately 40,000 km per year with government subsidies covering 30% of the purchase price premium.

Q: How do cities manage the grid impact of large-scale bus depot charging? A: Shenzhen's experience demonstrates that unmanaged simultaneous charging of 500 or more buses at a single depot can create 10 to 15 MW peak demand spikes that exceed local grid capacity. The solution involves three layers: smart charging management software that schedules charging based on departure time and electricity pricing, on-site battery energy storage systems (1 to 5 MWh) that buffer peak demand, and utility coordination to upgrade local transformer and feeder capacity. Shenzhen's smart charging implementation reduced peak depot demand by 42% while maintaining 100% on-time morning departure rates. The grid upgrade costs ($180 million citywide) were shared between the transit operators (40%) and the local utility (60%).

Q: What are the key differences between depot charging and opportunity charging for bus fleets? A: Depot charging uses lower-power chargers (40 to 80 kW) with overnight charging windows of 3 to 6 hours, requiring larger on-board batteries (250 to 400 kWh) but simpler infrastructure. Opportunity charging uses high-power chargers (300 to 600 kW) at route terminals for 10 to 20 minute top-ups, enabling smaller batteries (100 to 200 kWh) that reduce vehicle weight and cost. Depot charging suits fleets with daily ranges under 300 km and reliable overnight parking. Opportunity charging is preferred for BRT systems with high daily utilization (over 300 km) and short terminal layovers. Bogota's hybrid approach, combining both strategies, provides the operational flexibility needed for intensive BRT service at lower battery cost per vehicle.

Q: How should cities plan for battery replacement and second-life applications? A: Based on Shenzhen's fleet data, batteries reaching 80% capacity retention (the typical retirement threshold for transit service) still hold significant value for stationary energy storage applications. BYD has established a second-life battery program that repurposes retired bus batteries into grid storage systems, offering transit operators a residual value of 15 to 25% of original battery cost. Cities should include second-life provisions in procurement contracts, establish battery tracking and health monitoring from initial deployment, and plan depot space for battery swap and repurposing operations. Budget planning should assume battery replacement at year 8 to 10 of vehicle life, at an estimated cost of 25 to 35% of original vehicle price given projected battery cost declines.

Sources

• International Council on Clean Transportation. (2025). Heavy-Duty Vehicle Emissions: Global Status and Mitigation Pathways. Washington, DC: ICCT.
• Bloomberg New Energy Finance. (2026). Electric Vehicle Outlook 2026: Commercial Vehicles and Buses. London: Bloomberg NEF.
• Shenzhen Transport Commission. (2025). Shenzhen Electric Bus Fleet: Seven-Year Operational Performance Report. Shenzhen: STC.
• TransMilenio S.A. (2025). Electric Bus Integration in Bogota's BRT System: Operational Results 2020-2025. Bogota: TransMilenio.
• PT TransJakarta. (2025). Electric Bus Pilot Program: Performance Assessment and Expansion Roadmap. Jakarta: TransJakarta.
• Asian Development Bank. (2025). Financing Electric Bus Transitions in Asian Cities: Lessons from Early Deployments. Manila: ADB.
• World Bank. (2025). Urban Transit Electrification in Developing Countries: Cost-Benefit Analysis and Implementation Guide. Washington, DC: World Bank Group.
• BYD Company Ltd. (2025). Global Electric Bus Deployment Report: Operational Data and Performance Benchmarks. Shenzhen: BYD.