Offshore windfarms are connected to the power network on land via underwater cables that transmit the electricity produced by the turbines. Installing submarine cables is always a delicate operation, in particular when the transmission cable reaches land, where it generally needs to be installed underground.
Horizontal directional drilling (HDD) is a trenchless, environmentally friendly method that minimizes impacts to key infrastructure and protected areas and is ideal for the installation of transmission cables at the interface between land and sea. The technique involves the drilling of a steered pilot hole on the desired trajectory; once completed, the hole is enlarged to enable the pipeline to be pulled through it. HDD can be used in all geologies from soft soil to hard rock while achieving a high degree of accuracy.