In many countries the best onshore locations for wind farms are already developed, and the utilities are turning to offshore sites. The main attraction of going offshore is the enormous wind resource available. Average wind speeds can be 20 percent higher, and the resulting energy yield up to 70 percent greater than on land. The lack of obstacles such as hills, and the generally smooth surface of the sea, also makes the wind more reliable.
With more and larger wind parks set to be built offshore, major investments are needed to find ways to feed the power into the grid. The alternating current technology used in the first, smaller offshore wind parks is increasingly reaching its limits on account of the high reactive power demand of the cables. For wind farms distant to the coast, HVDC Light is the ideal means to bring the power to shore and to assure a good power quality.
The HVDC Light converter stations have a small station footprint and low weight - a fact that is of particular importance in the offshore station.
The on-shore (receiving) converter station can be located close to the shore or further inland. The grid is sometimes rather weak (radial structure) along the coastline, but this may not necessarily be a problem, since HVDC Light can be connected to weak points. But it is also easy to bring the connection point to a major substation at some distance from the shore by means of the HVDC Light cables.
The newest example of a HVDC Light wind farm transmission offshore is the 1200 MW Dogger Bank.
