Alex Hughes debates the pros and cons of converting RTGs to electric en masse
Lured by savings in energy costs and reduced emissions, major stevedoring operators around the globe are reassessing the financial case for converting existing diesel rubber-tyred gantry cranes to electric operation. But at an estimated average conversion cost of $250,000-$300,000 per unit and a possible return on investment of three to five years, it's certainly not a cheap option.
APM Terminals is very much at the forefront of this movement, having recently taken a decision to convert the majority of its existing global fleet of over 400 RTGs to electric operation over the next two to three years, with the contract to be awarded to a single provider to ensure standardisation and continuity.
Ross Clarke, director - design & operations for new terminals, tells Port Strategy that APMT prefers a bus bar system of electric conversion over a cable reel, although the bus bar requires the RTGs to retain their diesel engines.
“The on board diesel engines will be used to move RTGs between stacks and will remain in place until each unit is life-expired and subsequently scrapped,” he says, explaining that APM Terminal's policy is to obtain the maximum possible productivity from its yard equipment, therefore RTGs are not allocated to specific stacks, but rather moved around the yard in line with operational requirements.
As part of the conversion plan, bus bars will only be laid alongside stacks, making it imperative that the RTGs have some means of moving between them using an alternative power source. Indeed, Mr Clarke says that the diesel generators will be run on a fairly regular basis because of this frequent need to transfer units, which will ensure that the diesel engines do get sufficient running to keep them in good shape.
“The amount of hours they run will be dramatically reduced, but not to a level where we will encounter problems,” he says.
Asked about the business case governing the conversions, Mr Clarke says this is “very attractive”, pointing out that significant savings will be made in repair and maintenance costs on the diesel equipment. In addition, energy consumption will also fall and CO2 emissions be cut.
Claus Burger, director of the Conductix-Wampfler Group's E-RTG business unit, adds that, in his experience, there are two main drivers behind terminals seeking to adopt electric technology in the yard. Firstly, there is the rising cost of diesel fuel, while the other is environmental in scope, in a need to reduce CO2 emissions.
“While there is a clear environmental benefit to using electric RTGs, we have to say that terminals are, initially at least, attracted by the financial case,” he says. "Clearly, those terminals closest to city centres want to be seen as being more environmentally friendly and can often benefit from government financial aid to fund conversion projects.”
Quizzed about return on investment, he says this is dependant on the port operation in which the RTGs are involved, which essentially comes down to how many stacks there are and how many RTGs are deployed there. “However, on average, we would suggest an ROI is possible within around three years,” says Mr Burger.
Although global stevedoring groups such as HPH and Evergreen have provided Conductix-Wampfler with conversion work, its contracts have by no means been limited to this size of company. Yilport, for example, is a rather small operator, with an annual throughput in the range of 500,000 teu, prompting Mr Burger to suggest that almost any terminal could make a financial case to take the step towards all-electric operation.
Asked whether there are any disadvantages to making the switch, Mr Burger says that none have so far manifested themselves. To the contrary, switching from diesel power to electric power lessens the amount of diesel consumed, and maintenance costs fall.
Both men agree that, savings in energy costs, although difficult to quantify, could be substantial. At present, for example, a wholly diesel unit has to use resistors to burn off excess energy as heat whenever boxes are being lowered. APM Terminals has already experimented with a half-way house solution, whereby diesel units are equipped with energy storage devices, allowing excess energy to be recovered, stored on board and then re-used by the machine.
“These have proved extremely successful. However, APM Terminal's policy is to move towards eventually operating zero emission machines, hence we are going to convert the fleet to electric operation. However, the challenge to the industry remains to find ways of eliminating on board diesel generators and we know that investment is being made by OEMs with this in mind.”
Conductix-Wampfler is also acutely aware that terminals are seeking to sideline diesel generators on board their RTGs, which is to some extent possible using the cable reel system. But there are good reasons why this is not always suitable. Port layout and operation invaraiably dictate which system is acquired.
“Where there are a lot of stacks – 30 or above – and fewer RTGs – under 15 – the reel system is usually preferred. But in terminals where there are fewer than 15 stacks and more than 30 RTGs, the conductor rail system possibly makes more sense,” he says.
When asked if there are any other demonstrable advantages of being able to offer a greener terminal alternative, Mr Clarke suggests that if APM Terminals is offering a similar price and productivity to that of its rivals, the fact that it is trying to achieve a zero emission operating system might well tip the balance if a shipping line is trying to decide between two different providers.
“It might not be the deciding factor, but in combination with other factors it might help us to win business. Although primarily we are undertaking the conversions because it's good business, there's no doubt that it is also good for the environment. So making the decision to go all-electric is a win-win proposition,” says Mr Clarke.
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