For his doctorate, a TU Delft researcher has looked into whether it is possible to set up a 'hydraulic' wind farm at sea. His theory would mainly mean that wind turbines could become lighter.
Offshore wind energy is becoming a competitive European energy source. The growth of offshore wind manifests itself in the large wind farms being planned and built in the North Sea, achieving GW (GigaWatt) level capacities. In conventional wind turbines, there are heavy generators at the very top, which means that heavy towers are also needed. To give an insight: if generators weighed 1,000 kilos less, the tower would need to be 1,900 kilos less heavy.
Antonio Jarquin Laguna, for his PhD at TU Delft, investigated whether it would be possible to replace as many of those heavy generators as possible, thereby substantially reducing the weight of many turbines. Several wind turbines together could contribute hydraulic pressure, which would be converted to a central location.
Displacement pump
In the current application, the electricity produced per wind turbine in a wind farm is routed to a central offshore platform and conditioned there, before being transported by cables across the seabed to the coast. In this respect, an offshore wind farm can be seen as one power plant producing electricity through hundreds of multi-MW generators.
In Antonio Jarquin Laguna's concept, electricity production would be centralised in a wind farm, requiring only a few high-capacity generators.
Jarquin Laguna focused his research on a new way of generation. This way ensures the aggregation and transmission of wind energy within an offshore wind farm, where there is no intermediate electrical conversion until the energy reaches the central offshore platform.
This is done through water technology. In Antonio Jarquin Laguna's proposed concept, the conventional gearbox or direct drive is replaced by a positive displacement pump, through which pressurised water is introduced from the rotor nacelle assembly into a hydraulic network. The water is brought together under high pressure from the wind turbines of the wind farm and passed to the central offshore platform, where electricity is then generated by a Pelton turbine.
Simulated
Simulation formed an important part of his research. For instance, he did simulations of a (hypothetical) hydraulic wind farm where turbulent wind conditions occur. The performance of individual wind turbines was compared to that of a wind farm with conventional technology turbines, with the same wind farm layout and environmental conditions. The results indicate that, even with the turbulent wind and wake effects, the hydraulic wind farm is capable of producing electricity with a 'reasonable performance'.
By: Kelly Bakker
Source photos: Pixabay
