Crest of the Royal National Institution of Naval Architects - Click to return to the homepage


Air Products_March 2021


International Registries April 2021

Cyber Security 2021


Cadmatic April 2021

Sea Spark April to July 2021

A subsea surge of power

Offshore Marine Technology: 4th Quarter 2020

Ocean Power Technologies (OPT) has launched its Subsea Battery, intended to serve as an eco- friendly means of powering subsea equipment. The solution comprises a lithium-ion phosphate (LiFePO4) battery system, housed within an all-steel lifting frame, which can be deployed to a maximum depth of 500m and which offers a total nominal storage capacity of 132kWh. 

The product was designed to be free of heavy metals, measures 3m x 2m x 2.1m and weighs 6.7tonnes. As well as providing a power source for subsurface equipment and tools, the Subsea Battery can be used to provide “uninterruptible power” to offshore installations and platforms on a short- or long-term basis, OPT claims.

The company adds that the battery could meet the power needs of electric ROVs and AUVs, and is suited to operations in the offshore oil and gas, renewable energy and aquaculture sectors. The Subsea Battery's modular design enables users to link multiple units together when greater doses of power are required. 

OPT comments: “LiFePO4 batteries have extremely low self-discharge rates while in stand-by mode, storage or [transit], compared to other chemistries.” When combined with an efficient battery management system, users can maximise the amount of energy available for payloads, thus boosting the amount of time that the battery remains in an active state. 

The Subsea Battery can be integrated with OPT’s two PowerBuoy models. These are specially designed buoys that float over the point of use, and capture and store wave energy to recharge the battery. The buoys include: the hybrid PowerBuoy, which incorporates solar panels and a back-up 1kW engine, and which can store up to 2MWh of onboard energy; and the PB3 PowerBuoy, an 8.3tonne model that can supply power to subsea assets in ocean depths spanning 20m to 3,000m. The PB3 variant can also transmit data to remote shore facilities.