The wind blows steadier at sea than on land, creating more reliable energy conditions for the generation of renewable energy—a major opportunity to combat climate change without disrupting the lives of those people it will benefit the most. While offshore wind turbines are effective sources of energy, the sheer scale of these massive structures presents significant engineering and installation challenges.
Offshore installation is generally performed by jack-up vessels, which stabilize themselves via extendable legs. However, their use is restricted to shallower water, and the process is time-consuming, slowing installation project schedules.
The alternative, using floating crane ships for lift operations poses new challenges, including longer lift-times and precision positioning at up to 100- to 200-meter tower heights. With sensitive gearboxes, generators, controllers, and other components preinstalled in turbines, unexpected movements put delicate pieces of instrumentation—not to mention the structure itself—at constant risk of damage. If output expectations for offshore energy are to be realized, turbine deployment must become more reliable, safe and cost-efficient.
Balanced stabilizing technology
Based in the Netherlands, Seaqualize is a startup technology company with big ideas as to how work can be done safely and efficiently at sea. This innovative organization has developed a patented stabilization principle that neutralizes crane and load instability during a lift. Initially developed and deployed for material handling applications, such as industrial carousels in factories, the technology performed incredibly well.
"However, it soon became clear that the real opportunity for Seaqualize was to help with heavy loads in fiercely dynamic conditions," he explained. "Our technology was perfect for the complex and unpredictable challenges of open ocean stabilization."
At the same time, the Dutch Ministry of Economic Affairs started looking into solutions to support the rapid growth of the offshore wind energy industry.
Uncharted waters
In theory, vessels and cranes could be adapted with Seaqualize's "balanced heave compensation" technology to allow loads to remain relatively stationary during a lift, even with vessel movement. However, smaller land-based equipment applications were one thing; but how would the device operate under harsh sea conditions?
Experienced with simulation as a validation tool, Seaqualize began looking to tools they knew to virtually test their hypotheses. Beginning their test-phase with MATLAB-based simulations of the crane, the team soon realized that while this software allowed individual components to be modelled, a more complete, systems-level representation to answer critical questions was missing.
Additionally, Seaqualize engineers struggled to find a software application that could validate their calculations. This combined with a need to model sophisticated cranes—including hoisting cables, loads and rigging, vessel movement, and the offshore worksite—sent Schinkel searching for a turnkey solution.
"I found simulation tools used for offshore engineering, some which had great hydro-dynamics, but minimal mechanical capabilities," explained Schinkel. "Ship movements were okay, but a complete system simulation was not possible. Also, connecting these tools with MATLAB was particularly difficult."
Similarly, mechanical engineering software didn't offer much in terms of hydrodynam-ics or dynamic environments, making it difficult to account for variables essential to the project. Eventually, the search led to Vortex Studio, where Schinkel immediately recognized the value of software's combination of mechanical engineering and maritime applications.
"I read about Allseas—an offshore construction company specializing in pipelaying, heavy lift and subsea installation—training the crew of their pipelay vessel with a simulation developed in Vortex Studio. I also saw port crane simulators with incredible cable dynamics and materials handling capabilities."
"CM Labs’ software provided a quick, comprehensive visual representation for project validation. These points, along with the built-in connectivity between Vortex Studio and MATLAB, drove my interest and eventually my decision to purchase."
Concepts and drawings meet real-world
Although physical prototype construction and testing of the stabilization system remained several months out, Vortex Studio allowed Seaqualize to immediately investigate questions regarding the tool's effect on crane ship performance. To quantify the hydrodynamics aspect and the balanced heave compensation system's effect on the crane, a complete virtual prototype of the system was built in Vortex Studio.
"I come from the old code-based simulation world where things were tricky, and you hope that you can render the next second," concluded Schinkel. "It's never a problem with Vortex Studio. It just works."
"Running these simulations in the software, rather than constructing and testing physical prototypes, let us test multiple design alternatives and real-world scenarios quickly," noted Schinkel. "Vortex Studio let us tie all aspects together through simulation."
Working with the robust, multibody dynamics engine in Vortex Studio also brought some overlooked design issues to light. Understanding the interactions between the crane and its 200-ton load was vital for uncovering a situation where uncontrolled vibration may have damaged the crane or the ship itself. Left undetected, an issue like this could have proven catastrophic in downstream stages of development. Vortex Studio exposed this effect, allowing Seaqualize to solve the problem with some minimal design changes and load rebalancing—all testable within the software.
"This is easy in Vortex Studio. The software's worksite-wide, system-level view of the operation allows you to do anything, see everything, and understand the effects."
Astonishing Training Experience
Although the software was simple enough for the Seaqualize team to learn and use; Schinkel opted to accelerate his project further and sent a member of his team to a hands-on Vortex Studio training session, to increase user capabilities and productivity.
Vortex Studio's training sessions are focused courses that provide a human-to-human educational experience, building skilled users quickly. As a result, even small companies, like Seaqualize, are matching the engineering and simulation capabilities of much larger organizations. "Increasing the pace of innovation keeps startups like ours competitive,” Schinkel observed.
"Our simulation engineer quickly learned scripting and advanced functions, I'm impressed by the difference a week of training made—the number of product iterations and improvements we are now able to make in a week is nothing short of astonishing."
Ready to deploy
By 2020, Seaqualize intends on deploying the first stabilization system for field testing. This is the first step toward largescale deployment. Equipped with Vortex Studio, Seaqualize is working to enable renewable energy expansion into previously unattainable areas. With less risk of damage during the installation process, wind farms should become operational and profitable faster than ever.
"I feel like a pioneer by using simulation as part of our projects, both here in the Netherlands and across the offshore industry," concluded Schinkel. "We put much trust in the software, and that trust is being validated time and time again."