Feasibility of Operating a Heavy-Duty Battery Electric Truck Fleet for Drayage Applications

Abstract

Vehicle fleet electrification is regarded as one major pathway toward achieving energy independence and reducing air pollution and greenhouse gas emissions. Compared to light-duty and medium-duty vehicles, electrification of heavy-duty vehicles, especially Class 8 trucks, is more challenging owing to the battery size required to attain the driving range necessary for their operating goals. As drayage trucks generally have a limited daily mileage, return to a home base every night, and spend a large amount of time creeping and idling, drayage operation has been the first targeted application for Class 8 electric trucks. The feasibility of operating battery electric drayage trucks at the individual vehicle level has recently been demonstrated. However, questions remain as to whether these trucks are capable of meeting the needs of typical drayage operation at the fleet level. This paper presents a feasibility analysis of operating an electric truck fleet based on real-world operation data of a diesel drayage operator in Southern California. Second-by-second activity data collected from 20 trucks in the fleet were used to estimate the corresponding electric energy consumption and the state of charge of the battery using a microscopic electric energy consumption model. An algorithm for generating tours of drayage activity from the collected data was developed and implemented. Multiple scenarios with different battery charging and truck scheduling assumptions were analyzed. The results show that 85% of the tours could be served by electric trucks if there is opportunity for charging at the home base during the time gap between consecutive tours.

Underground Gravity Energy Storage: A Solution for Long-Term Energy Storage

“…The electricity generation capacity factor is 35% if the system is used at a 70% capacity factor. The energy storage capacity of a mine with 4,000,000 tons of sand and a 200 m average height difference is 1.74 GWh (4,000,000 × 1000 × 200 × 0.8 × 9.81/1000/1000/1000/60/60 = 1.74 GWh), which is slightly smaller than a usual daily pumped storage plant [59]. Higher average height differences in the UGES plant result in longer storage cycles and greater energy storage capacity.…”

Lift Energy Storage Technology: A Solution for Decentralized Urban Energy Storage

“…Assuming the lift operates 70% of the time storing energy, the capacity factor of the system is 17.5%. A building with 5000 containers and a 50 m average height difference has an energy storage capacity of 545 kWh (5000 Â 50 Â 0.8 Â 9.81 Â 1000/1000/60/60 ¼ 545 kWh), which is equivalent to the energy storage of an electric truck [54]. Note that the number of lifts in the building can increase significantly if the lifts are rope-free, as described in the discussion section.…”

Application of Wireless Charging at Seaports for Range Extension of Drayage Battery Electric Trucks

“…This solver is designed to minimize the objective function, thus the negative of (8) was provided as the objective function (−𝑓(𝑃 𝑊𝐶 )); minimizing −𝑓(𝑃 𝑊𝐶 ) means maximizing 𝑓(𝑃 𝑊𝐶 ). The constraint in (9) was included in the objective function formulation in a way that the zone plans with costs outside the specified budget range were penalized and thus not chosen as optimal solutions.…”

“…However, BETs are not a perfect match for drayage applications yet as a previous study revealed that a BET fleet is incapable of operating at the same level of a diesel fleet under similar operational conditions [9]. BETs were held back by the downtime they received, which was insufficient to significantly recharge their batteries.…”

“…Whereas for diesel trucks, that downtime duration was sufficient for refueling. The BETs in [9] were considered to be charged only at the base. It thus underscores the need for providing convenient out-of-base charging opportunities for drayage BETs, and wireless charging is one potential solution to achieve that.…”