The market for offshore support vessels remains depressed for the time being, but when it recovers, all newbuilds will have batteries.
Recent years have been challenging ones for the offshore support vessel (OSV) market, but as the market shows signs of recovery, battery and hybrid power is likely to form an integral part of OSV design, said Plan B Energy Storage (PBES) vice president marketing, Grant Brown.
Currently, PBES is bidding to supply batteries to several OSVs for a variety of integrators and owners. “As the slowdown in offshore oil is resolved, price per barrel of crude increases and demand for OSVs ramps up, many of the vessels currently in long-term layup will require significant mechanical and electrical upgrades to be recertified,” said Mr Brown. “This may be cost prohibitive and result in many – if not most – being removed from service.
“Subsequent demand for OSVs will be filled by newbuilds, which will be built to a higher standard of efficiency than in previous eras, often with a multipurpose design. Given hybrid technology’s effectiveness at delivering increased efficiency, we anticipate that new vessels will be built with energy storage as an option.
“We predict that all vessels will have a battery room, with options to have energy storage either integrated at the newbuild stage, or later if the customer is not initially willing,” Mr Brown told OSJ.
As he noted, the operational profiles of OSVs present some unique challenges for battery suppliers. They require rapid fluctuations in power response – from almost nothing to extremely high loads, often multiple times in a matter of moments.
This puts a propulsion battery through rapid cycling, often at high discharge rates. With a 15,000 cycle life and a 3C average charge/discharge rate over 24 hours, Mr Brown said the PBES battery system is ideal for this type of duty and provides twice the cycle life of the next closest available product. This is achieved, he said, thanks to the chemical composition of PBES cells, and the fact that they are liquid cooled, which allows high discharge rates without damaging the battery.
Further lifecycle benefits and performance are delivered by what PBES said is a unique solution called CellSwap, which allows users to replace the lithium cells without replacing the entire battery. Not only does this save on recycling at the end of a battery’s lifespan, but it also means that a new cell can be installed for 60% of the cost of buying a new system.
“The advantages of this are twofold,” Mr Brown told OSJ. “Firstly, it means that our battery systems can be built using smaller systems that can be recored after five years, rather than the marine industry standard of 10.
“Batteries built to last for 10 years are necessarily larger, compensating for degradation in usable capacity over time. The capital cost of installing the smaller battery is far lower and leads to a much faster return on investment, and saves on space and weight, which is at a premium for OSVs. The smaller size also allows users to capture advances in battery technology sooner.”
PBES batteries help power the hybrid cable layer NKT Victoria, one of the world’s most advanced and fuel-efficient cable-laying vessels. The vessel’s onboard grid allows the ship’s engines to work at variable speed, in combination with energy storage for peak shaving and enhanced dynamic performance, optimising energy consumption and reducing engine maintenance.
Energy storage is also used for back-up for shore connection during cable loading, a unique advantage which results in a more environmentally friendly emission-free mode for the ship.