Study on The Design Methods of Tall Wind Turbine Foundation (A Case of Adama I Wind Farm)
Samuel, Tadesse (PhD)
Wind energy has been deemed an appropriate means of diversifying Ethiopia's
energy mix while simultaneously addressing the deficit in electricity supply which the
country faces. The first wind farm in Ethiopia is Adama I wind farm, which generates
a 51MW of energy using 34 sets of wind turbine generators. The foundation
supporting the wind turbine generators is designed assuming the load encountered
to be static; however, wind turbine structures are inherently dynamic structures, and
the design of foundations for resistance of dynamic loading requires a different design
approach other than static approach. Both the static and dynamic foundation design
approach for wind turbine structure are studied in this project.
When designing the foundation taking into account the dynamic nature of the
structure, the final design resulted in the circular gravity base foundation with a
bottom diameter of 13.2 m, and depth of 3m. The reduction in dimensions of one
particular foundation is interpreted by the change in volume of concrete, which
showed a decrement of 124 m
when compared with the existing typical foundation
in Adama I wind farm.
Moreover, the foundation design to support all the 31 turbines is identical across 5km
stretch of wind farm land, and didn't cater to the local soil or rock condition. In reality,
the ground condition is different across the wind farm land; as result, the effect of
using different bearing capacity values on foundation dimension is also explored.
The final design resulted in the circular gravity base foundation with a bottom
diameter of 14 m, and depth of 2.5 m for all the bearing capacity used in the study.
The reduction in dimensions of one particular foundation is interpreted by the volume
of concrete, volume of backfill. The volume of the concrete showed 115 m
the backfill material decreased by 1,137 m
when compared with the existing
foundation in Adama I wind farm. The results of this part of study show that the
increasing the bearing capacity had negligible contribution in reducing the
dimensions of the foundation.
This project concludes that the bearing capacity is not the major limiting factor when
designing a foundation for the Adama I wind farm. The stability against overturning
is the most critical criteria for both the static and dynamic approaches. Furthermore,
when designing wind turbine foundation taking into consideration the soil structure
interaction and dynamic nature of the wind turbine generators, the foundation
dimension showed a decrement, which emphasizes the static approach to foundation
design is conservative.
Tall Wind Turbine; Adama; Wind Farm; Foundation
Addis Ababa University
Type of publication|
Addis Ababa - University of Addis Ababa
Added to C-A: 2021-02-18;06:59:09|
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