Planning for a sustainable future

 

Konecranes Port Solutions takes the long-term view that automation with electrification is the key to a sustainable future for the industry.

“In container terminals today", says Mikko Lepistö, SVP Business Unit Solutions, Konecranes “typical emissions are 13.5 kg CO, per TEU, of which 50-60% are direct [Scope 1], mainly due to use of fossil fuels, and 40-50% are indirect [Scope 2], mainly from using electricity generated from fossil fuels." 

The way forward is electrification and optimization of energy use, and automation is a natural corollary. "While you can't say that electric terminals are automated, the converse is almost always true automated terminals are electrified," said Lepistö, who was speaking at a Konecranes webinar in October.

Sustainability also improves safety and well-being (ergonomic working conditions), reduces noise and light pollution, and makes optimum use of space to reduce land use. "Automated terminals are simply more sustainable and safer places to work," he added.

"Recent history has also shown that the productivity and consistency of automated terminals are better than their manual peers. From a financial standpoint, automated terminals are simply better business," said Lepistö. "The best automated terminals also run at zero local emissions."

Based on studies by Portwise, the worst emitters are diesel straddle carrier terminals, followed by diesel RTGS and diesel terminal tractors. Improvements are offered in semi-automated terminals electric ARTGs plus diesel terminal tractors, and ASCs plus diesel shuttle carriers. The stand-out performer is the fully-automated terminal - ASCs plus electric AGVs. As, over time, more electricity is generated from renewable energy sources, their Scope 2 emissions will also decline.

Slow progress

The first automated container terminals appeared in 1993, yet today only 3-4% of terminals are automated and they only account for about 15% of global throughput. The perception remains that automation is only for large scale operations, but automation is scalable. As terminal operators take a more holistic approach (gate-in/gate-out), the benefits and returns become clearer.

Automated equipment also evolves. AGVs first appeared in 1993 and over time have become progressively cleaner. This was discussed at the webinar by Ralf Konnerth, director of automated horizontal transport at Konecranes (Gottwald). The first machines were diesel-hydraulic and diesel-electric drive was introduced in 2006. This has been followed by hybrid drive machines and machines with lead-acid batteries, and now machines with Li-ion batteries.

Drive efficiency

A basic question concerns AGV drive train losses. How much energy is needed to provide 1 kWh of usable power? The diesel-electric ratio is 3.86:1 (26% efficiency), the lead-acid battery ratio is 1.86:1 (53% efficiency) and the Li-ion battery ratio is 1.43:1 (69% efficiency).

In terms of CO, emissions, the diesel-electric AGV consumes 7.5 litres of diesel per hour. Including fuel production and transportation of 3.14 kg CO/litre, the overall result is 23.6 kg CO, per operating hour. The Li-ion battery electric AGV uses 13.2 kWh per hour. Charging efficiency is given as 85%. Adding in the electrical grid (15.5 kWh/hour) and the global energy mix (0.453 kg CO/kWh). the result is 7 kg CO, per operating hour. Konecranes has also evaluated on board battery charging with fuel cells and the result is not favourable compared with external charging of the batteries. The overall result comes out as 16.6 kg CO, per operating hour.

Lead-acid batteries have a long charging time, so battery packs need to be exchangeable and a battery charging station is needed (cf RWG & APMT at MV2, LBCT Long Beach). This is suitable for long, uninterrupted operations. An opportunity charging strategy is suitable where vehicles with Li-ion batteries stop at given locations during their normal cycle. This is the 'bus stop' analogy. A high number of chargers is needed, very high charging power is needed, and charger utilisation is low. It is not preferred for automated horizontal equipment as it adds further complexity to the Equipment Control System to manage the container flow while observing remaining battery run time. 

The most likely option for AGVs with Li-ion batteries is dedicated fast charging. It means the vehicle being taken out of the normal work cycle to charge. A small number of chargers is required and charger utilisation is high. Konecranes' latest analysis shows 1.5 hours of charging vs 19 hours of operation compared with 6.5 hours charging for Lead Acid and only 10 hours of operation.

Fast-charging requires specific types of cell technology in the Li-ion batteries, utilising High Energy Cells rather than High Power Cells, for opportunity charging. In addition, the design concept allows Konecranes to offer customer-specific battery sizes. An individual Battery Management System (BMS) manages battery status in the AGV as well as those being charged at the ACS.

Since 2016 Gottwald (Konecranes Gottwald) has delivered 18 automated charging stations for AGVs with Li-ion batteries, and there have been very few issues arising. They are pre-tested and housed in standard 20ft containers. The same technology is now available for the Konecranes Noell battery straddle carrier. Feedback of power back into the grid has been successfully tested.

"In summary," said Konnerth, "Li-ion technology saves > 10% energy compared to lead-acid batteries and no battery maintenance is required.  Total capex is considerably lower, in terms of civil engineering and charging technology when compared to a battery exchange station and building infrastructure."

Fleets of AGVs with mixed types of power are in operation and retrofits are possible.  Konecranes has a choice of two battery suppliers, which helps to secure deliveries in an overheaded cell market while managing cost. 

 

This article was written by World Cargo News and published in the November 2023 magazine issue.