Retrofit powering up Norwegian shipowner’s construction support vessel with battery storage for greener subsea ops

In pursuit of more sustainable operations, efficiency enhancements, and cost savings, Norway’s shipping player Rem Offshore has tapped a compatriot energy design and smart control systems firm, Norwegian Electric Systems (NES), a subsidiary of HAV Group, to furnish one of its construction support vessels (CSVs) with a deck-based battery energy storage system (ESS).

NES’ containerized energy storage system, which contains a ‘Quest’ battery charger, a 1 MW battery package, and a control system, will be fitted onto Rem Offshore’s CSV Rem Inspector, enabling the ship to operate in peak shaving, spinning reserve, and harbor mode.

Egil Bremnes, NES’ Sales Manager, explained: “Spinning reserve provides extra generating capacity that allows fewer generators to be used while maintaining the vessel’s DP class. This results in significant savings on operational costs and helps to reduce emissions.”

The 2013-built, 110-meter long, and 22-meter wide CSV Rem Inspector has a deck space of 1,000 square meters and is equipped with a 150-tonne crane. NES is expected to deliver the equipment required for the retrofit during the first quarter of 2025 and manage the project from its headquarters in Bergen, Norway.

Thanks to a multi-year deal with Equinor, the purpose-built Rem Inspector inspection, maintenance, and repair (IMR) vessel will undertake subsea operations covering IMR activities throughout the company’s assets on the Norwegian Continental Shelf (NCS), equipped with a module handling system (MHS) and three remotely operated vehicles (ROVs). The offshore start-up is targeted for April 2025.

Siv Remøy-Vangen, Managing Director of Norwegian Electric Systems, underlined: “Reducing energy consumption on offshore vessels is achieved through several measures, including integrating battery storage, energy management systems, and optimised propulsion.

“These efforts lead to both cost savings and lower emissions .Rem Offshore is committed to increasing fuel efficiency and providing customers with competitive, environmentally friendly vessels.”

Moreover, NES emphasizes that REM Offshore’s energy storage retrofit plans for existing vessels target fuel consumption and emissions curbs while maintaining operational reliability, thus, integrating batteries into the CSV is set to downsize the number of diesel generators in use while maintaining DP class, bringing significant operational cost savings while slashing emissions.

Lars Conradi Andersen, CEO of Rem Offshore, underlined: “We have recently ordered our first newbuild net-zero emission vessel which shows that sustainability and commercial priorities go hand-in-hand at Rem Offshore.

“Upgrading our current fleet is another key component of this strategy. NES has a strong track record of delivering energy storage systems to offshore vessels, which is why we have chosen them as a cooperation partner for the Rem Inspector.”   

Rem Offshore recently hired Corvus Energy to provide energy storage systems for its new energy subsea construction vessel (ESCV), which Myklebust Verft is building for the Norwegian shipowner.

Described as the first of its type to perform heavy construction work in offshore wind and subsea arenas with net zero emissions, the ship will run on methanol, thus, greater use of batteries is anticipated to enable more cost-efficient gains.