As it happens, nothing could be further from the truth. Electrification and automation go hand in hand, and automated straddle carriers are actually just as easy to electrify as their manual counterparts. The required technology is available and has already been proven in real-world use.

Plug in and go

The main reason that automated straddle carriers are the perfect solution for all-electric horizontal container transportation is that with Kalmar AutoStrad™, the charging times are integrated seamlessly into the automated job scheduling of the machines. In a traditional manually operated straddle carrier terminal, it's not unusual for the machines to spend over 30% of their time at idle. At an AutoStrad™ terminal, idle rates will be significantly lower, and any extra time between container moves can be utilised for charging, as a centrally controlled fleet of automated machines allows the charging stations to be used efficiently without queueing.

Kalmar currently offers all-electric options based on two different types of batteries. The Kalmar electric straddle carrier with high-energy battery is capable of up to four hours of continuous operation with a charging time of 45 to 50 minutes. As an alternative, the Kalmar electric straddle carrier with high-power battery (previously known as the Kalmar FastCharge™ straddle carrier), is capable of up to 50 minutes of continuous operation with a charging time of only five to six minutes.

The battery technologies are supported by two different charging options that can be combined flexibly. Both battery technologies support charging the onboard battery via a pantograph at a FastCharge station. FastCharge technology is ideal for Kalmar Automated Straddle Carriers, as it automatically connects the charger to a machine arriving at the charging station. Unlike fuelling diesel-powered machines, no human interaction is required. A standard CCS charging interface, compatible with any commercial charging station, is also available for use by technicians if the AutoStrad™ needs to be parked outside the automated yard area for a longer period.

Both the high-power and high-energy battery technologies are available for Kalmar AutoStrad™. The charging times for the electric machines will necessitate a slightly larger fleet, but the difference is more than offset by the better efficiency of the automated equipment. Based on running extensive amount of operation scenarios in digital twin environment, we currently estimate that an approximately 11% larger fleet will be needed available for operation for an all-electric AutoStrad™ terminal compared to traditional hybrid machines fleet.

Ready for the future

Electrification and automation are the logical next steps for container terminals around the world, as terminal operators seek to improve both their sustainability and their performance. The technology for electrifying straddle carriers is already available and proven in real-world operations, including at DP World's London Gateway logistics hub which has been piloting the use of battery-powered straddle carriers with FastCharge charging technology since 2018. Next year, the terminal will take delivery of eight fully electric Kalmar straddle carriers with the high-energy battery option.

A major benefit of automated straddle carriers is that they can operate flexibly as a single equipment pool, unlike traditional straddle carrier terminals that are generally organised with fixed equipment allocations for each quay crane. This uniform equipment pool helps minimise the operational impact of charging events, as any machine in the pool can carry out any task. The global equipment pool also minimises unladen driving, thus improving the energy efficiency of the operation. With the ability to optimise the usage of each machine – and with charging breaks integrated seamlessly into the operation – Kalmar Automated Straddle Carriers use less energy per container move compared to manual straddle carriers, making them the ideal way of combining the benefits of electrification and automation.