Acoustic regulation of wind turbines case study

Overview and background

Wind turbines are subject to stringent noise regulations, particularly in residential areas. To balance energy production with compliance, operators need precise wind data for real-time adjustments. Spica Technology partnered with FT Technologies to integrate our FT742 Acoustic Resonance Wind Sensors into wind turbine systems, enabling operators to maximise efficiency while adhering to local noise restrictions.

In residential areas near wind farms, operators face the dual challenge of maximising energy output while complying with local noise regulations. One of Spica’s clients was a French wind park owner who had nine 15-year-old Nordex N60 1.3 MW turbines situated on a site that overlooked a town in southwestern France. These turbines generated significant noise, necessitating careful monitoring to avoid community complaints. To mitigate noise, the owner had an agreement with the local town to shut down the turbines under specific wind conditions. In return, the town would compensate the wind park owner for lost production. Unfortunately, the cost of lost production often exceeded the calculated compensation. The reliance on outdated mechanical anemometers led to inefficiencies, as decisions were based on forecasts rather than real-time data. If wind conditions deviated from forecasts, turbines had to be manually restarted, increasing downtime and costs.

The challenge

When turbines are “de-rated” to meet noise regulations, energy output drops, negatively impacting profitability. Conventional wind sensors, like mechanical cup anemometers, often lack the precision required to achieve optimal balance between noise reduction and energy efficiency. Furthermore, these sensors can struggle in harsh environments, resulting in data inaccuracies or mechanical failures.
Spica Technology, founded in 1997, is a Danish company specialising in retrofitting wind turbines with advanced control systems. They developed a more effective solution that integrates accurate wind data from FT Technologies wind sensors seamlessly into the turbine control system.The goal was to enable wind turbine operators to adjust performance based on real-time wind conditions, optimising both noise compliance and energy output.

The solution

FT742 Acoustic Resonance Wind Sensors and Spica Technology Control Systems
The FT742 Acoustic Resonance Wind Sensor was chosen for its precision and resilience. Its unique Acu-Res® technology offers several key advantages over traditional sensors:

High accuracy: Provides real-time data on wind speed and direction that doesn’t degrade over time - critical for fine-tuning turbine performance.
Durability: Withstands extreme weather conditions, including heavy icing and strong winds, ensuring consistent performance in harsh environments.
Minimal maintenance: The sensor’s compact, solid-state design reduces the risk of mechanical failures, offering long-term reliability.

Spica Technology’s turbine control systems were adapted to incorporate the FT742 sensors, providing operators with continuous data that allows for real-time adjustments. By integrating the sensors into their control systems, Spica ensures that wind turbines operate within legal noise limits while maximising energy production.

Results

The collaboration between Spica Technology and FT Technologies delivered impressive results for wind farm operators:

Optimised energy yield: By enabling precise control of wind turbine speed, operators could reduce noise when necessary without significantly impacting energy production.
Improved noise compliance: FT742 sensors allowed turbines to operate within noise regulations, particularly in residential areas, avoiding fines and community complaints.
Reduced maintenance costs: Thanks to the FT742’s robust design, operators experienced fewer mechanical issues and lower overall maintenance requirements, leading to reduced operational costs.

One wind farm operator reported that after installing the FT742 sensors and Spica’s control systems, they could meet noise regulations more efficiently, with less frequent de-rating and higher overall energy output compared to traditional sensor setups.

Spica Technology’s Experience with FT Sensors

“The project has been a complete success. It was the sum of many different elements – the controller and the remote access resulted in improved availability. And the new FT sensors were a part of this solution. It is a part of the Spica DNA to always offer our clients the best technology available. When it comes to wind sensors we feel that the best product on the market for wind turbines is the FT sensor. That’s why we’ve chosen to partner with FT and retrofit their sensors. It is just obvious to us that if you need to change an old sensor you will go with the new technology that FT offers. FT is recognised within the wind industry as offering extremely high quality. We don’t even have to justify our decision to use their sensors to our customers as they already know that FT are so reliable. It’s like if you buy a car and it comes with Michelin tyres you just say, great. You don’t ask questions because you know and respect the brand. It’s the same with FT."

Benny Thomsen

CEO of Spica Technology ApS

“We are actually amazed that sometimes we see FT sensors that have been on turbines for over 10 years and they are in such good condition that you can’t even tell that they’ve been sitting on the top of a turbine for that long. And where we have customers with turbines in cold climates, we also feel the FT sensors are best. With their better heating system, they give much better availability for the turbine operator. 
The FT742-DM50 is a great new model. It is easy to align with the laser tool and, once fitted, you can be sure that it will always be aligned, even if you have to change it”

Anders B. Jensen

CTO of Spica Technology ApS

FT742-DM50 Wind Sensor

Designed for mounting on a 50mm outer diameter pipe, the FT742-DM50 wind sensor delivers accurate wind speed measurements up to 75 m/s. It features superior corrosion resistance, lightning protection, and an all-body heated design, making it ideal for use on wind turbines and in harsh meteorological conditions. For precise alignment, the FT742-DM50 can be easily installed using the FT039 alignment collar and FT040 alignment tool, ensuring reliable and accurate performance in the field.

View the FT7 Series