• Fujian Yongfu Power Engineering Co., Ltd.

    China Changle Offshore Wind Farm Area C Project

    Changle, Fujian, China

Project Summary

Designing Strong Wind Turbine Foundations

Fujian Yongfu Power Engineering built the 496-megawatt China Changle Offshore Wind Farm Area C, one of their latest facilities, 31 kilometers east of Changle in Fujian. The 58.6 square-kilometer area has an average water depth of between 31 and 45 meters, making it one of the world’s deepest locations for a wind farm. The area is frequently battered by typhoons that produce strong winds, turbulence, and frequent wind direction change, which required Fujian Yongfu to design particularly strong and stable foundations for each turbine. However, the foundations had to accommodate complicated geological conditions, including unstable, soft soil, and earthquakes. As a result, they needed to find a way to design the facility safely while keeping costs under control.

Frustrations with Traditional Design

Fujian Yongfu determined that to keep the facility stable they would have to build the foundations with suction pile frames. Though suction piles have been used for various offshore structures since the 1990s, they had not been deployed as foundations for offshore wind turbines. The design team soon discovered that they also could not rely on traditional methods of offshore wind design for this unusual design. Their initial attempt with these methods could not accurately simulate the interaction between the soil and a pile with such a large diameter. Fujian Yongfu then tried to use separate digital simulations of the interaction between the pile and the soil and the design of the frame itself, but learned that the two separate results were difficult to unify. Therefore, they needed digital design software that could unify soil analysis and digital foundation design to determine how to effectively use the suction pile method for wind turbines.

Unifying Soil Analysis and Modeling

Though Fujian Yongfu had previously used Bentley’s OpenWindPower Fixed Foundation for offshore modeling, they discovered that pairing it with PLAXIS would give them a unified design environment that would allow them to perform soil analysis and foundation design at the same time. They first used PLAXIS to perform a full analysis of the soil in the construction area that could also determine the potential effects of design options on the soil. Within that environment, they then simultaneously formed and optimized the design of the foundation in OpenWindPower Fixed Foundation while examining how the current state of the design would interact with the soil. The design team used a suction pile module within SACS to automatically import PLAXIS analysis, creating a composite model that shows both the current state of the model and its effects on the soil around it. With this information, they adjusted the model to increase its strength and stability.

Federating All Road System Data

As a result of synchronized soil analysis and digital modeling, Fujian Yongfu determined that the best type of foundation for the project would be a three-pile suction conduit frame. Since this type of pile has a larger diameter but a shorter length than other piles typically used for offshore wind facilities, they reduced the amount of steel needed for each foundation. With their foundation design, Fujian Yongfu ensured the wind turbines can withstand typhoons, shifting soil, and earthquakes. Compared to more traditional offshore wind turbine designs, the solution reduces costs by 30%, or more than CNY 400 million. Establishing 496 megawatts of clean energy in Fujian will eliminate the need to burn 535,000 tons of coal annually, as well as cut down on carbon dioxide emissions from various power generation sources by 1,462,600 tons. The design also helped Fujian Yongfu minimize environmental impact by sustaining water quality, minimizing erosion, and protecting marine and avian life.

Project Playbook: PLAXIS, OpenWindPower Fixed Foundation

Outcome/Facts
  • Fujian Yongfu Power Engineering needed to build a large wind farm in an area prone to typhoons, earthquakes, and shifting soil.
  • The design team used PLAXIS and SACS to simultaneously model potential foundation options and analyze their effect on the ocean soil.
  • Compared to more traditional offshore wind turbine designs, the solution reduces costs by 30%, or more than CNY 400 million.
  • The wind farm eliminates the use of 535,000 tons of coal annually and cuts down on carbon dioxide emissions from various power generation sources by 1,462,600 tons.
Quote:
  • OpenWindPower Fixed Foundation and PLAXIS allow engineers to take advantage of their seamless interface to optimize the design of wind turbine foundation structures such as single pile and suction pile.

    Fan Xia Ling Engineering Fujian Yongfu Power Engineering Co., Ltd.