The overview of the charging system is shown in Figure 1 which includes, but is not limited to:

• On turbine/ offshore substation power converter – converts the windfarm medium voltage AC power into DC power that is compatible with the CTV propulsion & battery system
• On turbine mooring/charging cable & connector deployment system ‘Reeler’
• Vessel connection & mooring system
• Control & safety system

The real time control system is provided to enable safe control of the charging system from both the vessel and windfarm control room and is designed to embed safety throughout the charging process.

The control & safety system has been developed according to marine classification society rules and standards, using MJR Power & Automation’s 25 years of experience of designing and delivering safety and mission critical systems to the commercial marine and offshore energy industries. A real time deterministic marine grade operating platform is combined with the added functionality of a web portal system used for the booking and monitoring of the wind turbine charging system from the vessel, the windfarm control room and via desktop access.

The control software has been developed for fully automatic, semi automatic and manual control of the charging and vessel connection system to provide maximum flexibility. The high-level control modes are as follows:

• Manual Control
• Follow Mode
• Mooring Mode
• Positioning Mode

Throughout the process of charging the vessel battery system, vessel personnel have full visibility of the status of the charging and deployment systems from the operator control station that is situated on the bridge of the vessel.

The web portal supplements the real time control system on the vessel and the turbine/offshore substation and allows asset owners and operators to access live data and analytics. It provides a means of booking, managing, authorising and remote real time monitoring of charging operations together with energy usage metering, carbon saving and emissions reduction data and billing. It also shows live information on vessel traffic, position and the status of the wind farm turbine chargers.

The secure web-based portal can be reached through mobile devices and desktop computers by users with the correct access privileges and complies with the latest DNV rules for Cyber Security. We appreciate that in a marine environment charge booking, authorisation and operations may be preferred to be carried out by VHF radio communication between the vessel and the windfarm control room. However, the offshore charging portal remains fully relevant in this case as it provides full desktop access to both real time and historical operational data, analytics and reporting.