Proven ABB technologies which deliver significant improvements in bulk carrier propulsion efficiency are rising to the challenges set by escalating fuel prices and IMO regulation under the EEXI scheme.
A new application of a proven technologies is set to achieve remarkable efficiency gains in bulk carrier performance, in a development which calls for a re-evaluation of ship propulsion options.
International Maritime Organization goals envisage cutting carbon emissions from ships by at least 40% by 2030, with ships also needing to join an EEXI (Energy Efficiency of an Existing Ship Index) and provide CII (Carbon Intensity Index) calculations from 2023. Alongside soaring marine fuel prices, the new regime is making owners receptive to innovation where energy saving is concerned, but few are willing to be ship propulsion pioneers.
Now, a fresh approach from ABB that combines two technologies already acknowledged in maritime circles for the efficiencies they deliver is reviving consideration of shaft generator systems as an impactful and practical replacement for conventional shaft line technology, in a solution fit for EEXI 2023 and beyond.
ABB shaft generator systems with permanent magnets at their core will be a key feature of the propulsion trains driving twelve 210,000dwt bulk carriers owned by the Bermuda-based Himalaya Shipping when they enter service from 2023 onwards. Built at New Times Shipbuilding in Jiangsu, China, the Capesize vessels will also include low voltage drives and transformers from ABB.
Shaft generator systems are acknowledged as offering the potential to cut ship fuel costs by 15–16% when compared to conventional shaft line technology because the set up allows ship operators greater flexibility to change engine loads when underway without starting up auxiliary engines. However, to date, higher upfront costs have proved insurmountable.
ABB says an extra 4% gain that can be squeezed out of the set up by factoring in its latest ACS880 single drive systems in combination with permanent magnets has decisively moves the goalposts.
The Himalaya Shipping order for a shaft generator application has been a true market breakthrough.
Jan Andersson from SeaQuest, Himalaya Shipping consultant, commented: “ABB’s latest series of shaft generators support our initiatives to ensure optimized ship efficiency, reduce CO2/NOx emissions and deliver maximum performance using less power in a package that is compact, robust and easy to maintain.”
Michael D. Christensen, VP and Global Segment Manager Dry Cargo, ABB Marine & Ports.
Michael D. Christensen, VP and Global Segment Manager Dry Cargo, ABB Marine & Ports explained that other owners had not been slow on the uptake. “With the first bulk carrier order including permanent magnet shaft generator systems using PM machine technology in hand, more orders are expected before the end of 2022. The solution has also been selected by MSC for installation on six large container vessels,” he said.
Within a more compact frame and by dispensing with the need for an excitation unit, the shaft generator system with permanent magnets is also around 20% lighter than a conventional shaft line set up and saves about 20% of space on board, he said.
Furthermore, at current fuel prices, Christensen suggested the solution offers payback within four years, with subsequent 20% efficiency gains then falling straight to the bottom line. The same gains would be available to bulk carriers of all sizes, he said, while alternative fuel types might make the payback period even shorter. Maintenance costs would also be lower due to the absence of the excitation units which require carbon brush replacement.
“Any kind of efficiency improvement to a vessel also provides a benefit where emissions are concerned,” he added, “but the shaft generator system gives a very concrete, here and now savings and demonstrable gains that can be added to the CII calculation. As one of the intentions of the new IMO rules is to compare performance between the same types of vessels, bulk carrier owners demonstrating energy savings are likely to benefit when bidding for charters.”
The capabilities of the new solution were also more flexible in operations and ‘more future-proof’ against evolving requirements on ship emissions, said Christensen.
“The ACS880 drive system ensures greater responsiveness for the changing power needs of an in-line shaft generator. The drive’s DC-Link also provides intelligent control of energy consumers such as auxiliary engines or thrusters, and energy sources such as batteries and fuel cells — with electrical power needs all distributed on a single DC buss. The power control and distribution gains available to shaft generator systems with permanent magnet will therefore continue to make a decisive contribution to shipping’s more sustainable future further down the line.”
Part of ABB’s role in the Himalaya Shipping project is to provide engineering, project management and commissioning services to the New Times Shipbuilding. With Hyundai Heavy Industries confirming that the shaft generator/permanent magnet combination would be part of the MSC container ship order in May 2022, Christensen drew attention to specific advantages for builders when permanent magnets become part of the project.
“With permanent magnet machines, there is no need to arrange for rotor magnetization because this is done by the permanent magnets: this means there are fewer items to install when compared to synchronous excitation machines,” he said. With no path in sight towards relieving pressure on ship fuel prices, however, Christensen also emphasized that fleet managers overseeing existing vessels could also consider their options on propulsion.
“In today’s market, very few owners and operators are likely to disregard a proven technology which offers an efficiency gain of up to 20%,” he said.