Vestas: How Large Can Wind Turbines Get, and Is Bigger Always Better?

Vestas was born 125 years ago as blacksmiths, but it wasn’t until the 70s with the oil crisis that they discovered an opportunity to mitigate oil prices by generating electricity from alternative sources. Similar to how a Formula One car generates downforce, the wind turbine is designed to push the air around the blades in a way that increases their rotation and generates as much energy as possible. And the sheer size of a modern turbine blade is a feat of engineering, reaching over 115 metres for their largest offshore turbines. But bigger is not always better. To be truly sustainable, Vestas also needs to consider the environmental impact of its turbine’s entire lifecycle. Through their sustainability strategy and circularity roadmap, they’re ensuring crucial components like glass fibre blades are recyclable, or that wind turbine towers can be made using low-emission steel.

In Vestas HQ, there’s a life-size shell of an old turbine housing a virtual reality center, which they use to show customers how the inside of wind turbine looks like. A similar system is used to train their service technicians to familiarize them with what the inside of a turbine looks like. One of their first turbines had a 15-metre diameter, but over the last 40 years, to reduce the cost of energy and make wind energy one of the most competitive wind sources, the trend has been to grow the size of the rotor to capture more energy from the wind. Over the next 20 years, there has been a substantial growth, and their biggest onshore turbine, V172, has 80-metre blades.

One of the most interesting challenges we have today is that this growth spanning from the 70s has been a strong enabler towards reducing the cost of energy and creating cheap, renewable energy. But this is also a level of scale in the industry that is orders of magnitude larger than what has been seen in the past. At the same time, one of the biggest challenges is that the increasing size of turbines, while historically having been an advantage, is not so clear going forward because the investments needed are huge. At the same time, the industry has gone from facing value chain challenges to transport challenges – every time you increase the size of turbines, different challenges emerge in how turbines are transported and installed.

Vestas has developed some very creative transportation solutions, but the level of challenges today are infrastructural – the size of harbors, the size of ships. It’s grown to an order of magnitude where, from a technology point of view, to continuously grow, it will not allow the kind of growth needed to meet climate targets. It’s is not so much about growing the size of turbines to be more efficient in capturing energy, but around how to increase their efficiency at their current size and industrialize them for the incredible growth that this industry needs to see over the next years to scale up to meet our climate targets and the ambitions for renewables as well as maintaining a level of competitiveness and ensuring a stronger capacity to support grids and electricity systems so that people never lose electricity.

Over time, wind turbines have evolved to be a three-bladed concept. Basically, the whole idea of the wind turbine is to catch as much energy from the wind as possible. Increasing the number of blades would somewhat add capacity to extract some wind energy, but at the same time would have a weight penalty that would contradict that energy extraction. So overall, what is important is the area, because that defines to some extent how much energy you can extract from the wind. Head of onshore product management at Vestas Pedro Pastilha says, “That doesn’t mean that we don’t have substantial technology innovations when it comes to materials, but when it comes to smarter turbines, when it comes to design optimization, I believe the overall concept of a three-blade turbine is here to stay.”

The typical wind turbine blade is roughly 50 meters, is built of glass fibre, and has a number of reinforcements on the inside to ensure its structural integrity over its lifetime, which typically ranges from 20 to 30 years or sometimes beyond that. They are built structurally in a way that is relatively similar to aircraft construction technology. There’s a shell made of glass fibre that covers the blade, often with carbon fibre reinforcements. The blades are then bolted into a hub, which is a rotating center piece that holds all three pieces of the blades, and then connects that with the gearbox, which is then what connects with the generator and how it produces electricity. Vestas very quickly became one of the biggest world’s consumers of carbon fibre and glass fibre because these turbines are growing in size. The problem? These materials have historically been challenging to recycle.

Wind turbines have to operate over different environmental conditions, including lightning – having a big blade sticking up in the sky is a huge way to attract electricity, especially also as they are made of carbon fibre which tends to conduct electricity quite well. All Vestas turbines are equipped with a lightning protection system which collects electricity from a lightning strike and drives it through the whole turbine into the ground to minimize any damage that could come from that lightning hit and doesn’t trigger damage to the turbine. It’s quite a thick wire because the currents that they take are quite substantial.

One key characteristic of wind turbine design is how fast the blades spin with the noise that they generate and the efficiency of their ergonomic profiles. The tip speeds need to be stabilized to be well below sonic wind speeds, because that would increase the noise substantially. This is a key priority for the introduction of wind, especially as you go closer to people’s homes. It is also a key design driver for the turbines and in defining their operating modes.

In many ways, from an aerodynamics perspective or a theoretical perspective, the way a wing profile works is very much the way a Formula One wing works to generate downforce, where you see that it’s more rounded on one side and more concave on the other. That is designed to generate suction on one side and pressure on the other side that basically pushes the blade. In an aircraft, you want that blade to be pushed upwards. In a race car, you want it to be pushed downwards. In a wind turbine, you want to increase the rotational torque of the wind turbine, which is inevitably the energy that you convert into electricity. The physics principle is exactly the same. The wind speeds and the scale they are designed for are very different, but the profiles would be very, very similar.

Vestas uses profiles that have been designed for NASA, as well as those used in aviation and aerospace. “The physics of it is relatively simple with all the complexities that come with aerodynamics but how you optimize for this specific case of wind capture is very specific and very particular and very different,” says Pastilha. “There’s a lot of engineering work that has gone into this to differentiate what we have in a wind turbine over what you would see on a race car or on an aircraft.”

“I come from a mountainous area in mainland Portugal where there has been a lot of wind development, and there’s a wind farm very close to my parents’ house, which is Vestas turbines. To me, it’s just a natural evolution of the old windmills that we used to produce flour to make bread,” says Pastilha. “We are now using the same concept to generate electricity. There is a beautiful historical accuracy. When you drive around areas that have huge wind turbine electricity production, you will often see that the areas where they’re positioned are peppered with old windmills. There is a lot of respect for the wisdom that came from the people before that were able to put the old-school windmills in the same locations that we now identify as optimal through advanced algorithms to install renewable energy and wind farms.”

Another big challenge that the industry will face over time is that these turbines require maintenance, and it’s a big focus to make them as maintenance-free as possible. But like any other thing that runs for 20-plus years, there is predictive maintenance and corrective maintenance that needs to happen, and there’s a huge workforce of technicians that support this operation that is spread globally in all kinds of locations. Over time, that workforce will continue, so the demand for employment of qualified service technicians will continue growing. There’s a huge opportunity for wind also as an employment area, which is hugely diverse because we operate turbines in all over 80 countries and they require local deployment of qualified technicians that are ready and prepared to maintain these turbines. This revolution that we will see in renewables also carries a huge opportunity for differentiated and qualified employment across many, many countries.

Turbines can range from 70-80 metres to up 175 metres. “It takes several minutes, often up to half an hour, to take the elevator all the way up, as we are talking about a significant height, says Pastilha. “It does feel like you’re going on quite a journey as you head up, and of course everything starts moving a little bit as you’re up in those heights. It’s quite an exciting journey to go up one of these towers that often sit on top of mountains, and you really feel like you’re on top of the world when you get to the top. It’s quite exhilarating to see.”

The design of the turbine needs to take into account a number of factors including aerodynamics, aesthetics and efficiency. A digital thread is a really important part of this. The role of enterprise-wide PLM in supporting companies like Vestas who are facing challenges of cost, logistics and the pace of innovation is huge. Vestas is highly focused on sustainability. A very important aspect for investors has been blades can have a second life and be redesigned and re-utilized into other applications, but also potentially into redesigning and rebuilding new blades from the existing ones that are in the market right now.

Vestas has very ambitious targets for sustainability. Sustainability is an important topic for PTC, and for all our customers around the globe. The first challenge is choosing the right materials upfront. It’s super important, as it affects how you account for the materialization during the product design. And then, at the end of the life of the product, with the amount of material content companies have to recycle. Second, it’s about the factory. We are helping companies to make better decisions about the manufacturing processes; some of them might have lower electricity consumption, for example.

Even before a product is out in the field, we can also simulate component and product longevity and validate that with real-world data when the product is operating and being serviced in the field. The goal is that sustainability becomes something that our customers can configure when they offer their products to their consumers. And this is where PLM really comes into the picture. PLM can help ensure that when companies are designing products, sustainability is a clear and conscious choice. From the materials the designers are selecting to how you are configuring your products in terms of the reuse of components to which suppliers you are choosing, now designers can pick something that does not compromise the integrity of the product, does not blow out the cost, which is very important, but at the same time is environmentally friendly.

Huge thanks to Pedro Pastilha for showing us around the Vestas headquarters in Aarhus, Denmark.

Please rate, review and subscribe to our bi-weekly Third Angle episodes wherever you listen to your podcasts and follow PTC on LinkedIn and Twitter for future episodes.

This is an 18Sixty production for PTC. Executive producer is Jacqui Cook. Recording by Peter Nørgaard Mathiasenst. Sound design and editing by Clarissa Maycock. And music by Rowan Bishop.