Automatic Route Generation And Cable Network Optimization For Offshore Windfarms

Hermann Kugeler

Dr. Venkata Jasti

By Dr. Venkata Jasti and Hermann Kugeler
September 30, 2021

As global warming and climate change continue to impact the planet in many ways, there is an increased demand for renewable energy sources. While land-based renewable energy technologies have been largely commercialized throughout the world, there has become a need to move power production offshore to harvest the large energy resource available, and reduce the need for land use that is often costly in coastal locations. Wind speeds offshore are also generally higher than on-shore, and have less turbulence, which means power can be more efficiently harvested.

For these reasons, many Asian and European countries have begun implementing offshore wind to increase their renewable energy generation, but the United States is just now beginning to develop its offshore wind infrastructure. The global offshore wind capacity rose above 30 GW in 2020, and is expected to experience continued rapid growth in the years and decades to come. President Biden has set an ambitious goal to install 30 GW of offshore wind in the U.S. by 2030. This is 1000x the U.S.’s installed offshore wind capacity as of 2019. While the U.S. is somewhat late to the game in terms of offshore wind adoption, it provides the opportunity to leverage existing technologies and tools that have been used commercially elsewhere. It also provides the opportunity to look at the European and Asian markets and figure out ways of improving designs, reducing costs, and streamlining the project development process.

Opportunity for Improvement in Cable Design Practices within Windfarm Planning

There are several project planning tools on the market that have been used around the world to plan and develop layouts and designs for offshore windfarms. These tools help developers optimize the design and layout of a windfarm based on the location’s wind resource, estimated performance based on wind capture modeling, and development costs. While these tools are helpful in optimizing the above-surface infrastructure, they skip over a critical piece of offshore windfarm infrastructure: the subsea power cables. Many of these software tools were initially developed for land-based windfarms, where the cabling wasn’t a significant cost factor in terms of the overall project cost, and construction practices are much more accommodating, but for offshore windfarms the cable costs become a much more significant portion of the overall project cost. Much of the west coast United States has deeper waters that make fixed offshore wind infeasible, and require floating offshore wind. The cable costs get magnified as floating windfarms move further offshore, and into deeper waters, where the costs and challenges of laying cables increase. The National Renewable Energy Laboratory (NREL) has estimated that the cabling cost for a floating offshore windfarm off the coast of California equates to approximately 16% of the total capital expense for the project, and this percentage is expected to rise as the cost of wind turbines and the floating platforms become cheaper.

Current methods require a cable route engineer to manually design and select the power cable network, and associated hardware after the above surface windfarm design and layout has been completed. This approach could result in a costly or impractical power cable design, that the developer either has to accept or iteratively re-design the above surface infrastructure to accommodate. In either case, the project developer and owner see an increased cost; either from the cable installation, or re-design services, and time delays if re-design is required.

An opportunity exists to use automatic route generation and cable network optimization tools that can integrate earlier into the windfarm optimization process allowing for significant cost savings.

Current Route Planning Capabilities

Makai has developed a software tool built on top of and leveraging the world’s #1 software for planning submarine cables, MakaiPlan. MakaiPlan has an established geographic information system (GIS) framework that is well suited to process and visualize terrain and related data. Since MakaiPlan’s inception in the 1990s, Makai has constantly improved this software and added substantial functionality related to submarine cables, including the physical properties of cables, installation costs, and installation methods.

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