Introduction from an energy point of view

Energy point of view Jacket Foundations for Wind Turbines Fisker Jensen, J. (2010)

At present, power generation context points out the need of increasing the energy production coming from renewable sources. Wind energy is a key source to increase significantly the share of renewable in the energy mix. Initialy, onshore wind farms were developed and their deployment is widespread in countries over the world. Presently, onshore wind farms can compete against conventional energy sources.

The next step to extend the use of wind energy is to develop and build cost-effective offshore wind farms. The reason is that wind resources are greater offshore and the amount of energy that can by captured by wind farms in the sea is significantly higher than in onshore areas. As a result, off-shore wind industry is moving towards wind farms located in areas further from the coastline where wind blows at higher velocities and more frequently. This means the deployment of turbines in ever deeper waters.

From the energy production point of view, it is interesting to consider larger wind turbines that can capture more energy from the wind. These will have higher rated power values and their annual energy production will be much greater. Taller towers will allow them to intercept stronger winds, and should lead to increased capacity factors. However, large OWTs (Offshore Wind Turbines) must be able to withstand harsher loading conditions due to the higher wind speeds and more extreme wave conditions in areas far from the shore. Press here....

Introduction from an environmental point of view

The current necessity to increase the power output from renewable energies has encouraged offshore the wind farms be moved progressively further offshore where there are higher wind speeds and, consequently, a higher power output can be obtained.

Jens Christensen Jens Christensen. Common mussel on turbine structures at Horns Rev. Danish Offshore Wind - Key Environmental Issues.

The design of foundations for offshore wind turbines at sea is based on long time experience in projects undertaken by the oil and gas industry. The marine conditions and the soil consistency will define the foundations typein order to ensure a long life cycle of the system. Jacket foundations seem to be the dominant option for pffshore wind farms (OWF) in deep water.

The identification of the environmental impact associated with each of the phases of an OWF project is based on the idealization of generic effects. Rigorous impact identification can only be addressed through the contextualization of the wind farm, both in terms of technical characteristics and energy efficiency, as well as location and extent of the farm. The main differences of wind farms installed offshore are laid in the highly technical issues of the construction, operation and maintenance phases of the projects. The possible impacts of decommissioning are unknown due to lack of experience. New solutions should ideally be found in order to increase the life time of the system and minimize the environmental impacts. Press here....


In the current context of the development of OWF in deeper waters, the use of jacket substructures takes the lead compared to other types of support substructures. There are different types among jacket substructures, but four-legged jacket are preferred in the wind industry. Pre-piled sleeve-pile connections are widely used in the industry. It is important to optimise the design of grout joint connections that can withstand the demanding conditions as we move into deeper waters.

Therefore, the objectives of this project are the following ones:

  Model a typical grout joint used in the industry under design loading conditions using Finite Element analysis.

  Compare existing standards for the design of grout joint connections.

  Estimate wave and wind loads in an OWT supported by a jacket substructure.

  Review of environmental impacts during the construction and operation of OWFs.

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