Globally, nations are rising to the challenge of ending their reliance on traditional fossil fuels. While nuclear has provided a cleaner solution for half a century, the problems created by the depleted fuel rods leaves many countries looking instead at renewable energies. These include solar, tidal, and wind, to name just a few.
For wind power, in particular, the race is on to develop giant wind turbines for offshore use, where developers have learned that they can site ever taller and more numerous turbines, capturing consistently stronger winds that are more reliable.
Across Europe, China, and the USA, private companies are racing to develop the most efficient giant structures capable of turning wind into energy.
In Europe, General Electric Renewable Energy has entered the final development phase for a development already dubbed 'The world's largest offshore wind farm.' In this final phase, the plan is to create a wind farm in the North Sea that will consist of 87 of its Haliade-X14 MW turbines, building a wind farm capacity of 1.2 gigawatts of power. In comparison, the largest onshore wind farm in Europe is a mere 600 MW, located in southeastern Romania.
To help understand just how far and how fast wind turbine technology has come, it is worth noting that the Romanian wind farm, created in 2008, consists of 240 individual turbines, almost three times the number of wind turbines, yet it generates only half the power of GE's planned development.
The same giant Haliade X14 turbines from GE have been approved for deployment offshore in the USA to create America's first offshore wind farm to complement its growing onshore wind farm sector. This project will add 800 MW to the tally for wind-generated power. As with the X14s under construction for Europe, these turbines have a boost mode that allows up to 15 MW power generation.
Thanks to the increasing blade size, fewer wind turbines are required to achieve these immense outputs per wind farm. Larger turbines and longer turbine blades result in greater efficiency, thanks to improved aerodynamics, a fact that has driven turbines to grow from around 30m in length in the 1990s to nearly 300m today.
Last year, Danish wind turbine manufacturer Vestas announced that they plan to install a 15 MW prototype at Western Jutland, Denmark, in late 2022.
Part of the drive for ever-larger turbines is economy of scale. It is cheaper and easier to install one 14 MW wind turbine in the sea than to site two 7 MW turbines. Saving will also occur through the need to service fewer sites.
In China, MingYang Smart Energy has announced plans to make the tallest turbines in the world. Equipped with three 118m blades that will sweet across a distance of more than half the length of the world's longest container ship, The Ever Ace, these 242m high behemoths will generate 16 MW of power. Each should be able to power 20,000 homes for their lifespan, predicted to be around 25 years.
Yet this push for ever-larger wind turbines raises questions about the maximum size and when we will reach it. Longer blades are more flexible and prone to vibrations. Vibrations, if left uncontrolled, can reduce performance and damages parts. The colossal power generation also puts a more significant load on the gearbox and transmission, while the ever-increasing size and weight of these structures demand more robust support towers and foundations.
One thing that is for sure - engineers are not ready to call time on these projects, and the size of wind turbines is set to continue growing for the foreseeable future. It is estimated that these 15-16 MW wind turbines will each displace over 38,000 tonnes of CO2 per year, roughly the equivalent of 25,000 cars, making them one of the most potent weapons in the arsenal against environmental change, second only to solar energy.
With these ever-larger turbines at our disposal, combined with solar and other renewable solutions, the hope that a cleaner future will soon be a reality. The only questions that remain are how long will this transition take and just how large will these wind turbines become?