WIND turbines are the Marmite of renewable energy: you either love them or you hate them.

Donald Trump famously threw a tantrum about them appearing off the coast near his golf course at Menie in Aberdeenshire. They have been accused of being noisy, intrusive, dangerous to wildlife and a blot on the landscape.

Onshore turbines are hugely important for energy generation; they currently make up more than 70% of installed renewables capacity in Scotland.

But Trump is not the only one to criticise the aesthetic impact of wind infrastructure (ironically, given his fury, offshore wind farms aren’t so much of a problem as they’re not nearly as visible as their onshore equivalents).

Other critics also consider that onshore developments compromise vistas across beautiful countryside. They include Ramblers Scotland, which has claimed they are destroying Scotland’s unique countryside and Mountaineering Scotland, which is also concerned that some developments are detrimentally affecting the mountain landscape.

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There is a strong counter argument that rows of slowly spinning turbines have a haunting, mesmeric beauty. If they are an art form to some, however, they are an overwhelmingly uniform one. Small wind farms, big wind farms, solo turbines – you see one, and you’ve pretty much seen them all.

This is not purely because of a lack of imagination to date in design. Current turbines, known as horizontal axis devices, are generally highly efficient in a way that is difficult to replicate in other configurations.

However, they do have weaknesses, such as being able to capture wind in only one direction, so losing their efficiency when the flow becomes unpredictable.

Two Lancaster University students, Nicolas Orellana and Yaseen Noorani, won the James Dyson Award last year for a radical new design called the O-Wind Turbine. It uses a 25cm spinning sphere sitting on a fixed axis and works with the wind blowing in any direction, making it particularly suitable for urban areas.

Another even more unconventional potential solution is the Autonomous Tethered Aerostat an airborne wind turbine developed by the Boston-based company Altaeros Energies.

This tethered blimp-like device looks like a giant tyre and floats in the air at a height of more than 100 metres. It provides a very different visual alternative to the traditional design, but its main benefit is that can harness the stronger winds found at altitude, also reducing ground noise and speeding up the investment payback period.

Another advantage of the helium-filled AWT, which is assembled from the same material used for advanced racing sailing yachts, is that it is more visible to birds than the current horizontal axis turbines, which have been accused of being damaging to wildlife.

Other possibilities for the future include vertical axis turbines – originally conceived as a sail design by the ancient Persians – and bladeless inventions using spinning discs.

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There are also whale fin, helical shaped, windspire, windbelt, spiral drag and sky serpent designs, most looking as exotic as their names. But at present little has moved beyond, or even as far as, prototype stage.

Dr Sergio Campobasso is a Senior Lecturer in Renewable Energy Engineering at Lancaster University and an authority on wind turbine design. He says that efficiency and aesthetics are competing issues: “There is a theoretical limit in terms of the energy that can be harvested from the wind, and the horizontal axis model is quite close to that.

“Some people do find that design boring. There are alternatives such as the vertical axis model, where the blades are parallel to the shaft, which may be considered more attractive. “The efficiency of these isn’t quite as high and there have been some issues with wind flow, but with progress in materials and better understanding of aerodynamics this design is being revisited.

“However, there isn’t nearly the same technological and financial support as is dedicated to the horizontal axis design. The biggest vertical axis being developed in the UK is 50 kilowatts, which is still in the small turbine range.”

Dr Campobasso says the sector is not lacking in imagination, with a team in Turkey working on a tower with oscillating wings aimed at mimicking the aerodynamics of the hummingbird – the only bird capable of hovering like a helicopter. But once again challenges with the wind dynamics and flow will have to be overcome. Tethered turbines above the ground also face issues.

“One of these is upscaling, as the prototypes have been constructed at a relatively small scale. They may be fine for generating a few kilowatts, but if we are talking about wind farms with each turbine requiring to generate megawatts, then the route from that prototype is quite long.”

Another difficulty of this model is installing a weighty electrical generator on the floating turbine and then getting the power to the ground via a cable. “The Massachusetts Institute of Technology (MIT) is looking at this and potentially it is doable, but it requires investment.” All this, he concedes, means that we are probably going to be looking at conventional and controversial horizontal rotors on onshore wind farms for at least another decade.

“However, potentially we will be able to develop turbines that present an interesting visual alternative to the existing ones. It will depend ultimately on the amount of resource industry and governments devote to this.”

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The Herald’s Climate for Change initiative supports efforts being made by the Scottish Government with key organisations and campaign partners. Throughout the year we will provide a forum in The Herald newspaper, online at herald.scotland.com and in Business HQ magazine, covering news and significant developments in this increasingly crucial area.

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