In offshore operations, being able to track and predict wave heights is critical for establishing the ‘operational window’ within which it is safe for supply vessels, maintenance boats and davits to operate. The wider the window, the greater the opportunity to make efficient use of service assets and engineering personnel. OCTOPUS takes these traditional methods further by providing vessel response forecasts, rather than just taking wind and wave conditions as the limiting parameters for vessel operation.
Today, offshore wind turbines are larger than ever before. New generation turbines for Europe and the US stand 230-260 meters tall and feature rotor diameters to generate 13-15 MW. Installation farther out to sea, or at least in deeper water, often makes it harder for land turbine inspection and maintenance crews. An operational headache for service providers and contractors, delays can also quickly reduce the output from the turbine array.
Weather forecasting software, vessel positioning systems and heave compensation technology provide additional capabilities for support vessels which, used individually or collectively, can widen the safe working window for operations. They help vessel operators decide whether a voyage should be undertaken, the vessel can hold station alongside the turbine, and if a connecting walkway can be deployed or it is safe for divers to work underwater.
Robots in the wind
Increasingly, however, drones are proving highly effective tools in undertaking remote structural survey work in the marine and offshore industries. Remotely operated vehicles and autonomous underwater vehicles provide high-performance diver substitutes for investigating cable integrity and substructures.
Funded under the EU Horizon Project, ATLANTIS is a pioneering infrastructure pilot offshore facility off the Portuguese coast at Viana do Castelo. One of its key objectives is to demonstrate how robotic technologies can be deployed to support greater efficiency in offshore wind farm operations. Support vessel operations and maintenance are estimated to account for up to 30 percent of the total cost of energy for offshore wind power. ATLANTIS aims to reduce the ‘levelized cost of energy’ (LCOE) by reducing or eliminating reliance on conventional support vessels for inspection and maintenance operations.
ABB plays a key role in ATLANTIS and has developed an analysis of data from the project which indicates that using robotic solutions to undertake inspection and maintenance duties at the turbine would increase acceptable wave heights for operations from 1.5 to 2 meters. As a result, safe vessel operations could take place 46 percent of the time, as opposed to the current 34 percent. In other words, using robots should increase the operational weather window by an eye-catching 35 percent.
OCTOPUS optimized for offshore
ABB’s broader contribution to ATLANTIS over the last 2.5 years has centered on developing a new version of ABB Ability™ OCTOPUS – the heavylift vessel sector’s preferred hydrodynamic/motion behavior monitoring and forecasting advisory software increasingly favored in container shipping. Soon, ABB will launch an ‘offshore-optimized’ version of OCTOPUS whose additional capabilities are expected to be decisive in removing a key operational obstacle to offshore wind industry development.
“Safe transfers of personnel between a support vessel and an offshore turbine platform are often the limiting factor in maintenance hours, as during rough seas crews cannot land by walkway or from the air,” comments Jimi Lipponen, responsible for digital services at ABB Marine & Ports. “ABB Ability™ OCTOPUS for offshore includes a dedicated mission planning tool which takes into account acceptable vessel responses, rather than solely the wave conditions. It calculates the extent to which vessels deploying robotics-based maintenance, rather than personnel, can work across a wider operational window.”
The result is a significant step forward for asset management in offshore wind support, with OCTOPUS software enabling safe and effective planning for installation and maintenance work at offshore wind farms.
“OCTOPUS Offshore mission planning will support smarter decision-making, increasing uptime for windfarm vessel owners and charterers, helping ship managers to make the right call on vessel deployment and ensuring a safer working environment for crews and maintenance engineers,” Lipponen says.