How Offshore Wind Comes Onshore*
Landfall refers to the point at which the cables carrying power from an offshore wind farm reach the shore. This is where the offshore and onshore infrastructure is connected – an important step in bringing renewable wind energy into the power grid. It takes about two years to construct the four stages of landfall.
Stage 1 Run the cable from the seafloor to a location a short on land. To put this cable in place, a hole is drilled using a technique called horizontal directional drilling. The hole starts in a small pit behind the dunes or a beach, and is then bored using a drill rig machine.The drill head is then pulled back through the hole, bringing with it a pipe from a cable installation vessel. After this, a cable can be fed through the pipe, establishing a path for the wind energy to be brought ashore.
Stage 1 Run the cable from the seafloor to a location a short on land. To put this cable in place, a hole is drilled using a technique called horizontal directional drilling. The hole starts in a small pit behind the dunes or a beach, and is then bored using a drill rig machine.The drill head is then pulled back through the hole, bringing with it a pipe from a cable installation vessel. After this, a cable can be fed through the pipe, establishing a path for the wind energy to be brought ashore.
Stage 2 Create the transition joint bay. The transition joint bay is usually constructed in a parking lot, for ease of access.
Stage 3 Undergound transmission to the substation. From the transition joint bay, cables run underground to a substation. Depending on the location of the substation, the underground transmission line could be several miles long. Like other utility pipes and cables, it tends to run lengthways underneath a road.
This means digging a trench where the cable will be laid. Construction is coordinated with local authorities to limit disruption to traffic, residents and businesses, keeping as much of the road open as possible, as well as access to properties.
This means digging a trench where the cable will be laid. Construction is coordinated with local authorities to limit disruption to traffic, residents and businesses, keeping as much of the road open as possible, as well as access to properties.
Stage 4 The final stage in getting renewable power from the offshore wind farm to the distribution grid is the substation. This is where the physical connection is located, and where the current is converted to the right voltage and frequency to be fed into the grid.
* Source: Orsted, a leading offshore wind developer.