Electric vs. IC Forklifts: A Green-Efficiency Showdown

Executive Summary

For decades, internal-combustion (IC) forklifts—fuelled by diesel, gasoline or LPG—dominated material-handling. Their electric rivals were confined to niche, light-duty indoor work. That hierarchy is crumbling. Driven by lithium-ion chemistry, high-efficiency permanent-magnet motors, tightening emission rules and volatile fuel prices, electric forklifts now match or exceed IC trucks on productivity metrics while slashing total-cost-of-ownership (TCO) and virtually eliminating site emissions. This article dissects the two power-trains through a “green-efficiency” lens—quantifying energy flow, carbon burden, air-quality impact, noise, maintenance burden and economic payoff—to answer a single question: which technology wins when sustainability and productivity are equally weighted?

1. Power-train Architecture: How Energy Becomes Motion

1.1 IC Forklift

A four-stroke engine converts chemical energy into heat, then mechanical work through controlled explosions. Only 18–22 % of the fuel’s lower-heating-value reaches the wheels; the rest is lost as exhaust heat, friction, pumping and idling. A hydrostatic transmission adds a further 12–15 % loss.

1.2 Electric Forklift

Grid electricity is stored electrochemically (lead-acid or lithium-ion) at ≥95 % round-trip Coulombic efficiency. An inverter feeds a 3-phase AC motor whose shaft efficiency is 91–96 %. Eliminating the multi-speed gearbox and replacing it with a single-stage reducer (~97 %) yields a well-to-wheel efficiency of 72–78 %—three times higher than the IC path.

2. Energy Cost per Moved Ton

Using a 2.5 t capacity sit-down counterbalance as reference:

Metric Electric (Li-ion) Diesel IC

Average energy draw @ 60 % load factor 7.8 kW 10.2 L/h

Energy price (U.S. industrial 2025) $0.10 kWh⁻¹ $1.10 gal⁻¹

Hourly energy cost $0.78 $2.96

Pallets moved per shift (8 h) 180 162 (power fade)

Energy cost per pallet 3.5 ¢ 14.6 ¢

Electricity wins by 4×, and the gap widens where carbon pricing or demand charges are absent.

3. Carbon Footprint: Scope 1, 2 & 3

3.1 Tail-pipe (Scope 1)

Electric forklifts produce zero CO₂, NOₓ, CO or PM at point of use. IC models emit:

2.68 kg CO₂ per gallon diesel

0.18 kg NOₓ (GHG-equivalent 298×)

0.04 kg PM₂.₅

In a 200-truck fleet running 2,000 h y⁻¹, diesel exhaust equals 9,600 t CO₂e yr⁻¹—the same as 2,100 passenger cars.

3.2 Up-stream (Scope 2)

Even when charged on the 2025 U.S. average grid (428 g CO₂ kWh⁻¹), a Li-ion forklift emits 34 g CO₂ per kWh of useful work. The comparable diesel figure is 220 g—6.5× higher. In regions with >50 % renewables (California, Pacific Northwest), electric intensity falls below 18 g, approaching carbon neutrality.

3.3 Battery Manufacturing (Scope 3)

A 25 kWh Li-ion pack adds 3.1 t CO₂e during mining, refining and cell production. Amortised over 8,000 h service life and 7 MWh delivered, this equals 0.44 g CO₂ per kWh—<1 % of diesel’s life-cycle figure.

4. Local Air Quality & Occupational Health

OSHA’s 8-h CO limit is 35 ppm—routinely exceeded in non-ventilated cross-docks using LPG trucks. Electric adoption at a 1.2 M ft² grocery DC in Illinois cut employee sick days by 28 % and lowered HVAC make-up air requirements, saving $0.15 ft⁻² yr⁻¹ in heating energy.

5. Acoustic Efficiency: Noise as a Pollutant

IC forklifts register 86–96 dB(A) at operator ear; OSHA requires hearing protection above 85 dB. Electrics run at 60–65 dB(A)—equivalent to normal conversation. A 10 dB reduction halves perceived loudness, enabling 24-hour goods handling in urban micro-fulfilment centres without violating night-time ordinances.

6. Duty-cycle & Productivity Benchmarks

Critics contend batteries cannot match the “continuous” nature of IC trucks. Data say otherwise:

Lithium-ion: 1–2 h opportunity charge during lunch restores 30–40 % energy; no battery swap needed.

Lead-acid: 15-min roll-out swap keeps trucks in service >95 % of shift.

A 2023 MHEDA cold-storage trial found electric trucks completed 22 % more pallets per hour than propane units, thanks to consistent torque and faster lift speed (0.45 m s⁻¹ vs 0.32 m s⁻¹).

7. Maintenance Efficiency: Fewer Parts, Fewer Fluids

Electric power-trains contain ~300 moving parts versus 1,200+ in an IC engine. Eliminating engine oil, spark plugs, DPF, EGR and SCR trims:

70 % fewer labour hours (10 h yr⁻¹ vs 36 h)

50 % lower parts cost

Zero waste-oil disposal (≈750 L over five years per diesel truck)

Over a 10,000 h life, maintenance savings amount to $12,000–15,000 per unit.

8. Total Cost of Ownership (5-year, 2,000 h yr⁻¹)

表格

复制

Cost Element Electric (Li-ion) LPG IC

Purchase price (2.5 t) $32,000 $25,000

Battery & charger $9,000 —

Incentives (30 % EV credit) –$9,600 —

Net CapEx $31,400 $25,000

Energy + fuel $7,800 $29,000

Maintenance $6,000 $18,000

Residual value $9,500 $3,500

5-year TCO $35,700 $68,500

Electric delivers a 48 % cost advantage and ROI in 14 months when operated two shifts.

9. Emerging Technologies That Tilt the Field Further

Silicon-carbide inverters push motor efficiency >97 %.

350 V fast-charge adds 50 % energy in 10 min, enabling 24/7 steel-foundry duty.

Vehicle-to-grid (V2G): idle forklifts supply 2 kW peak-shave, earning $400 yr⁻¹ in utility credits.

Solid-state batteries (Toyota, QuantumScape) promise 40 % higher energy density and 15-min charge by 2028.

IC countermeasures—hydrogen ICE, renewable diesel, Euro Stage V—cut particulates but cannot erase the fundamental Carnot-limited efficiency of combustion.

10. Application Matrix: When Does Each Win?

Application Recommended Power Rationale

Enclosed high-rack warehouse (>12 m) Electric Zero emissions, tight aisle, regen lowering

Cold-chain (-25 °C) Electric Lithium cells pre-heat; no cold-start issues

24/7 port container handling IC (H₂/diesel) 20 t lift, no charge windows, outdoor

Rough-terrain lumber yard IC High ground clearance, debris tolerance

Urban last-mile hub Electric Noise ordinances, variable load, incentives

Explosive atmospheres (ATEX) Electric No hot exhaust, sealed motors

11. Regulatory Tail-winds

EU Stage V + CARB OHV 2024 force diesel forklifts into costly after-treatment.

U.S. Inflation Reduction Act §45W grants $20,000–60,000 per commercial EV.

China’s “Non-road” GB 20891-2022 effectively bans diesel indoors in tier-1 cities.

Manufacturers have responded: Toyota, KION, Hyster-Yale now allocate >60 % R&D budget to electric platforms; Cummins supplies battery packs instead of engines.

12. Recycling & Second-life Circularity

Li-ion packs retain 70–80 % capacity after 8,000 forklift hours. Repurposed into stationary storage for solar-powered charging depots, they provide 5–7 years additional revenue before hydrometallurgical recovery recovers >95 % Li, Ni, Co. IC engines, by contrast, are aluminium-iron hulks with contaminated oils requiring energy-intensive re-melt.

13. Conclusion: The Green-Efficiency Verdict

Across every metric that unites ecological responsibility with economic rationality—energy efficiency, carbon intensity, local pollution, noise, maintenance and lifetime cost—the modern electric forklift outscores its IC counterpart by factors ranging from 2× to 10×. Only in ultra-heavy, outdoor, continuous-duty niches does combustion retain a narrow edge, and even here, hydrogen fuel-cell electrics are rapidly encroaching.

For fleet managers, the decision is no longer “Can electric do the job?” but rather “How soon can we phase out carbon?” With utility incentives falling, battery prices at $89 kWh⁻¹ (2025 spot), and carbon pricing spreading, each month of delay now costs money. The green-efficiency showdown is over; electric forklifts have taken the belt.