RIFT Supporting Innovative Wavesub Tidal Power Generation

Industry : Power Generation

Client : Marine Power Systems via Partner Severn Subsea (Severn Glocon)

Product : RSUB

Summary

RIFT was approached by a partner (Severn Subsea) in 2017 to assist in aspects of the automation of an offshore tidal power generation system. The generator, to be tethered 35m under water off the Pembroke coast, utilises wave and tidal movements to generate electricity.

Overview

RIFTs partner is a highly experienced solution provider in the offshore space. Supporting the development of an innovative power generation system to generate electricity. With a 12 month development cycle and a year sea trial to plan for, RIFT was engaged to handle the automation of the valves controlling the submerged ballast tanks in the Wavesub.

Challenge

Offshore, subject to submersion of up to 50 meters, represents a key challenges. The ballast system runs internally from a 24V DC power rail but has minimal internal power available. Configurable torque, failsafe and proportional control were requirements for the fine control of the ballast system. Low maintenance and long life are also a key requirement and add to the engineering difficulties involved. Permanently submerged electric actuators in a brackish water with the temperatures and pressure problems related to the environment created a unique set of challenges.

Solution

8 RIFT Subsea actuators were developed for this unique environment. Following depth certification testing at LP Bently the units were certified as safe to use at depths of up to 800m. The units did not fail at this depth that was the limit of the test available at the time. RIFT supported the installation and commissioning of the units and the Wavesub.

The RIFT controlled ballast solution enables the Wavesub to accend or descend under the sea as required to optimise its power generation from subsea wave motion. The units performed a range of sea trials and full operation of the trial Wavesub commenced in 2019. The unit spent a number of years and sea with no problems related to the actuation system, yearly checks and maintenance were performed and RIFT is the chosen partner for the ballast solution if the project moves into full scale operation and production.