Proven ship efficiency gains available from shaft generators including permanent magnet technology can now be secured for a payback of under four years, according to ABB.
Shaft generator systems have been installed on small and medium-sized ships since the beginning of the direct current (DC) era, but the recent steps to make the inclusion of permanent magnet technology cost effective has made the option compelling for a far wider audience. Simply defined as rotational electrical machines that take power from the main propulsion engine to produce electricity, today’s shaft generators are more efficient, lighter and more compact than ever before, with even the largest ships now candidates for installation.
ABB Marine & Ports has secured a leading position across the merchant shipping markets as a supplier of new generation shaft generators including permanent magnet technology. The combination of permanent mag- nets shaft generators and ABB’s ACS880 drive deliver
a system which can achieve efficiency gains of up to 20 percent compared to a traditional diesel generator, the supplier says.
Based on current fuel prices, ABB calculates that drawing Power-Take-Off (PTO) from the main engine to generate electricity instead of powering up the auxiliaries will mean payback can be achieved within four years or less, depending on fuel type used.
“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%,” said Michael Christensen, Global Segment Manager for Cargo, ABB Marine & Ports.
Also critical is the contribution the system makes to reducing ship emissions, added Christensen, in line with the general requirement for a sustainable shipping future and new IMO regulations on emissions (EEDI/EEXI, CII), including CO2. “Our permanent magnet shaft genera- tors offer a flexible, market-ready means of achieving efficiency targets as they are defined in CO2 emissions per capacity mile within the IMO regulatory framework,” he said.
From both designer and user perspectives, however, it is also the inherent simplicity of the new generation of shaft generators which has been winning hearts and minds. The system offers connection via a DC-Link to ABB’s
ACS880 drive system provides intelligent control of energy sources like shaft generator, auxiliary engines, thrusters, batteries and fuel cells, with all of the vessel’s electrical power needs distributed using a single DC bus. Christensen’s assessment of owner enthusiasm for the solution is strongly supported by ABB’s recent references. Following accelerating orders for permanent magnet shaft generators from roll-on, roll-off, bulk carrier and container ship, ABB reached a milestone order from COSCO Shipping covering ten newbuild containerships and has since then become the solution provider for the world’s four leading container lines.
Deliveries also included a landmark deal to equip twelve 210,000dwt bulk carriers owned by Bermuda-based Himalaya Shipping. Built by New Times Shipbuilding in Jiangsu, China, these Capesize vessels also include low voltage drives and transformers from ABB.
Other high-profile orders include installation of systems onboard a pair of 130-meter length CO2 storage vessels operating as part of the Northern Lights carbon capture and storage project (CCS), due delivery by China’s Dalian Shipbuilding Industry Company in 2024.
Alongside the increased flexibility and functionality available to ACS880 drive systems, owners are attracted to the solution by the ease with which it can be installed and maintained, as well as its compact profile, added Christensen. “The PM machine is around 20 percent smaller - and 20 percent lighter - than the equivalent synchronous excitation machine.”
With the permanent magnets providing rotor magnetization, the set-up does away with the need for separate equipment, which reduces the number of components at the installation stage. The absence of the excitation ma- chine also disposes of carbon brushes – which require frequent replacement.
Christensen also pointed out that the efficiency gains brought by the ABB shaft generator system could work their way to fewer genset running hours - reducing maintenance – or even as consideration of lower installed genset power.