Science

Vertical wind turbines are the future of wind farms

What if we had it all wrong from the start when designing and building horizontal axis wind farms? A new study suggests that when grouped together in specific ways, overall efficiency can be increased by 15% with vertical axis wind turbines, challenging many current projects.

Recently, researchers at Oxford Brookes University found that the design of vertical axis wind turbines is much more efficient than traditional wind turbines in large scale farms, and when placed in pairs, vertical axis wind turbines increase each other’s efficiency by up to 15%. Placed in series, the power produced increases by a further 3%. That is a total gain of up to 18% depending on the configuration.

To obtain these numbers, the research team, from the School of Engineering, Computing and Mathematics (ECM) at Oxford Brookes University, led by Professor Iakovos Tzanakis, conducted an in-depth study based on more than 11,500 hours of simulation. computer science. The simulation aimed to show that wind farms can operate more efficiently by replacing traditional horizontal axis wind turbines (HAWT) with compact vertical axis wind turbines (VAWT). But the researchers themselves were amazed at the results, recently published in theInternational Journal of Renewable Energy (ELSEVIER).

The future of wind farms must be vertical

The results show, for the first time on a realistic scale, the potential of large-scale VAWTs to outperform current HAWT turbines. VAWTs operate with a vertical axis (relative to the ground) and exhibit the opposite behavior of HAWT turbines that we are used to seeing. According to the study, VAWTs increase each other’s performance when arranged in a grid. And no matter the type of design, the positioning of wind turbines is essential to maximize yields.

This study shows that the future of wind farms must be vertical. Vertical axis wind turbines can be designed to be much closer to each other, increasing their efficiency and ultimately lowering electricity prices. In the long term, VAWTs can help accelerate the green transition of our energy systems, so that cleaner, more sustainable energy comes from renewable sources. Says Professor Tzanakis. These results are a real springboard towards the design of more efficient wind farms, the understanding of techniques for recovering wind energy on a large scale.

Time is running out, the pressure is on

What are the deadlines that we should respect for the deployment of a maximum of wind farms in order to best fight against climate change? According to the Global Wind Report 2021, time is running out… According to the figures put forward, for the deployment of this technology to be effective in this fight, we should do it three times faster over the next decade (compared to 2010 -2020) in order to achieve the “net zero emissions” targets by 2030 – aimed at avoiding the worst climate impacts.

Modern wind farms are one of the most efficient ways to generate green energy, but they have a major flaw: As the wind approaches the first row of wind turbines, turbulence is generated downstream. . And this turbulence affects the performance of the following rows », Explains Joachim Toftegaard Hansen, lead author of the study. ” In other words, the first row converts about half of the kinetic energy of the wind into electricity, while for the back row this figure drops to 25-30%. Each wind turbine costs more than 2.3 million euros / MW. As an engineer, it naturally occurred to me that there had to be a more cost effective way “.

This study is the first to comprehensively analyze many aspects of wind turbine performance, in terms of grid angle, direction of rotation, turbine spacing and number of rotors. It is also the first research to determine whether the performance improvements are valid for three VAWT wind turbines installed in series.

The importance of using computational methods to understand the physics of flows cannot be underestimated. These types of design and improvement studies are a fraction of the cost compared to huge experimental test facilities. This is especially important during the initial design phase and is extremely useful for industries trying to achieve maximum design efficiency and power output. Explains Dr. Mahak, co-author of the study and lecturer at ECM.

International Journal of Renewable Energy (ELSEVIER)

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