There’s an undeniable trend towards making wind turbines larger in order to cut costs. This is especially relevant to offshore wind power, where larger wind turbines can be hidden from sight by moving them further from the coastline.
The move towards larger but fewer turbines also has implications for maintenance costs. ExxonMobil, the maker of the circulating oil Mobil DTE Heavy Medium, has developed synthetic lubricants for wind turbines that deliver high levels of equipment protection and a longer oil life, but even with the best lubricants, some maintenance will always be needed. Travelling between multiple turbines is more problematic offshore than on land, so fewer turbines make more sense. The wind at higher altitudes is also stronger and steadier, so it has more potential for power generation.
The UK wind farm at Burbo Bank in the Liverpool Bay recently saw the completion of the new 8MW wind turbines, each being 195 metres tall, which is higher than the Gherkin skyscraper in London. While these are certainly impressive, six US institutions headed by the University of Virginia are planning what would be the largest wind turbine in the world at 500 metres high. To put it into perspective, this would tower over anything on the London skyline (The shard is currently the largest structure at 306 metres.) and only be slightly shorter than the One World Trade Center in New York (541 metres).
Of course, while bigger is usually better when it comes to wind power, scaling wind turbines up this much inevitably brings technical challenges, so the researchers are questioning the fundamentals of wind turbine design. One major revision is dropping the number of blades from three to two to reduce the overall weight and cutting costs, with the inevitable loss of efficiency being mitigated by a new aerodynamic design.
Onshore wind turbines are already sometimes thought of as blots on the landscape, so such a huge turbine will typically be located 50 miles or more out at sea, where harsh storms are not uncommon. The researchers therefore took their inspiration from the palm tree, which endures high winds by bending and adapting to the flow. The proposed giant wind turbine will act in a similar way, with the blades positioned downwind rather than upwind, so they can bend away from the tower to withstand heavy gusts.
There are, of course, many other challenges to address with such a huge structure, but if successful, it could take offshore wind power to a completely new level.