Automation poses some tough power supply-related questions for ports, says senior project manager Peter Mallin.
For all the advantages over diesel, electrical automation puts much more demand on a port’s power supply. Traditional quay cranes often have peak demands of around 2000kVA. While a typical automated stacking crane (ASC) may only peak at 50% to 60% of that, an automated terminal could easily be looking at two or three dozen of them – so drawing several tens of thousands of kVA when operating a full stretch.
Automated rail-mounted gantries (ARMGs) and stacking cranes (ASCs) don’t need to ‘see’ to work and can be operated at night without floodlights, so there’s some saving on illumination. And power can be regenerated from the lowering of containers. But these don’t cancel out the large step up in power demand between non-automated and fully automated terminals. An estimated rise of around 25% is likely when switching from electric rubber tyred gantries to ASC operation on a like-for-like basis.
Installing back-up power will require several megawatts per berth, which doesn’t come cheap. A 10MW back-up system will cost in excess of US$4M. It can also be a challenge to find enough space in the heart of a port. The 10MW system would typically occupy 420m² and the loss of operating area has to be balanced with the amount of revenue per hectare that might be lost.
Keeping the lights on
Most big ports are situated in areas with well-developed infrastructure, but some high-volume facilities may lack a guaranteed electrical supply all year round. Power outages can lead to severe financial penalties and the reputational damage is difficult to calculate. There is also the safety question of leaving loads swinging in the breeze. Taking these factors into account makes it far easier to justify the cost of providing back-up power.
Automation tends to be tackled in phases, moving from one set of equipment to another but each stage can build up issues for the next. Layouts of equipment, logistics and associated ducting and cabling have to be carefully considered. Laying down the right power infrastructure is a challenge. But failing to act will make stepping toward full automation a problem later on.