Helwin Beta

The HVDC (high voltage direct current) HelWin Beta converter station is installed in the German North Sea at a water depth of 23 meters, located 55 kilometers off the German coast. The platform collects electricity generated by offshore wind turbines and plays a key role in converting the generated alternating current into direct current for export into the German electricity grid. 

Iv was responsible for the detailed design of the topside, the workshop drawings, the connecting bridge with the adjacent HelWin Alpha platform, and the procurement of non-high-voltage-related equipment. Siemens, the main contractor for the project, awarded the construction contract to Heerema Fabrication Group (HFG), with HFG Engineering responsible for the jacket design.

The distance from the platform to the receiving station in Büttel, where the connection to the German electricity grid is made, is 130 kilometers. To minimize energy loss during transport over this long distance, the collected electricity on the platform must be converted from 155 kV alternating current (AC) to 320 kV direct current (DC). This conversion is carried out by the offshore HVDC converter station HelWin Beta, with a maximum capacity of 690 MW.

The generated 33 kV AC from the wind turbines is first converted to 155 kV AC and then to 320 kV DC on the HelWin Beta platform. The transport in direct current minimizes energy loss and ensures efficient energy transfer to the onshore station. During the conversion process, a significant amount of heat is released, requiring an extensive cooling infrastructure, including a water cooling system and HVAC system. This system ensures that the equipment’s temperature remains within the optimal range of 18 to 25°C.

The HVDC converter station HelWin Beta has a maximum capacity of 690 megawatts, enough to supply approximately 500,000 households with energy. Through efficient conversion and minimizing energy loss during transport, this project contributes to a more reliable and sustainable energy supply for Northern Germany.

HelWin Beta is designed as an unmanned ‘daughter’ platform, normally operated remotely from the control center in Lehrte or from the onshore station in Büttel. Together with the ‘mother’ platform HelWin Alpha, it forms a robust offshore energy infrastructure.