Your benefits

Welcome to ROMO Wind, the independent and exclusive provider of the unique iSpin system, a revolutionary approach to wind measurement.

The iSpin spinner anemometer measures the wind where it makes sense: in front of the rotor at the spinner, where the wind hits the turbine first. Our goal is to provide you with better insights for full wind turbine performance. For the first time in the history of measuring wind at wind turbines, there’s a unique possibility to prevent loss of productivity of your turbines and to enable deep insights in wind conditions by simultaneously measuring all significant wind parameters.

The iSpin advantages at a glance


With iSpin, you will be able to verify the efficiency of your wind turbine by monitoring the power curve. iSpin lets you know when acute and chronic influen-ces are impacting the performance.


With iSpin, you can increase the productivity of your wind turbine. iSpin identifies and helps you to adjust previously undetected yaw misalignment.


With iSpin, you can increase the life of your turbine by reducing loads. By correcting yaw misalignment and using the iSpin turbulence and flow inclination data, you can improve the management of your wind farm. You can profit from shorter down-time and lower maintenance costs.

iSpin is like a contact lens for your wind turbine, providing whole new level of transparency for turbine productivity.

iSpin is able to measure parameters at the nacelle which until now have been difficult or impossible to accurately measure.

The following further abilities of iSpin allow uniquely deep and accurate wind condition insights.
For details on each of these features and background documents please visit our Knowledge centre

With iSpin you can monitor if the air density corrected power curve declines or improves 


You can monitor and correct yaw misalignments to get more revenues and lower turbine loads 


Observe turbulence intensity allowing you to make informed choices between power production and reduced turbine loads.


Monitor flow inclinations


Use the accurate iSpin wind data as a reliable basis for your operation strategy, for repowering or expanding your wind park


Compare original wind assessment with actual wind conditions in all wind sectors


Turn your turbine into a virtual wind met mast


iSpin technology

Learn more about this innovative technology, see how iSpin works and participate in the most relevant findings we compiled for you.

Introducing a new technology

The three ultrasonic iSpin sensors measure the wind directly at the spinner, in front of the rotor, where the measurements are undisturbed by rotor turbulence. In contrast, today wind turbine wind sensors all measure in the turbulence behind the rotor.

With the innovative spinner anemometer technology, wind conditions can be measured more accurately than ever before.

Benefit from this new technology for more productivity, deeper insights and a longer life for your turbine for a better return on investment.

Romo_wind_total_1 copy2

iSpin uses three ultrasonic sensors mounted at the spinner
iSpin is designed logically: the sensors are installed in the front of the wind turbine, where the wind hits first.

The spinner anemometer iSpin is superior to other technologies when carrying out 360° wind measurement.
The iSpin produces high precision power curves under all conditions. The images below show power curve data of the same wind turbine from a wind farm where the nacelle anemometer, a nacelle LiDAR, a met mast and the iSpin recorded the wind speed data from all wind sectors. Only the iSpin was undisturbed by terrain effects and wakes from the other turbines in the wind farm.


  • Wind speed hitting the turbine
  • All flow inclinations (including the horizontal flow inclination – the yaw misalignment)
  • Free wind speed
  • Turbulence intensity
  • Rotor speed and position
  • Nacelle position
  • Air pressure (in order to determine the air density)
  • Temperature (in order to determine the air density)

In addition, the Power Production can be measured when analysing the SCADA data.

Read more about the iSpin technology –
the revolutionary approach to wind measurement

In bringing iSpin to the market, ROMO Wind is commercialising spinner anemometer technology invented and patented in 2004 by Professor Troels Pedersen from DTU Wind Energy at the Danish Technical University (DTU).

Professor Pedersen had long recognized the inadequacy of data provided by the nacelle anemometry conventionally mounted behind the rotor, on the nacelle. On this location, sensors collecting wind measurement data to control basic functions, such as start-up and shut-down, only measure wind disturbed by rotor turbulence.

The nacelle anemometry is therefore not sufficiently precise for performance monitoring and it cannot measure the yaw misalignment or the turbulence intensity hitting the turbine. Correcting yaw misalignment and accurate power curve monitoring enable significant production gain and load reduction.

iSpin is the only measurement technology, which enables simultaneous measurement of all these important wind data.

For more details and background documents please visit our Knowledge centre.

How iSpin works

Power curve
Does your turbine achieve its full potential?

Yaw misalignment
Is your turbine always correctly aligned to the wind, and so fully
productive, or is it subjected to excessive loads?

Turbulence intensity
What kind of damaging turbulence and slip-streams occur at your turbine?

Flow inclination
From where and how strongly does harmful flow inclination hit your turbine?

iSpin measures the wind speed and yaw misalignment in all wind sectors.
In addition, the iSpin technology is also able to provide information about air pressure and temperature.
This enables you to correct the measured power curve for seasonal variation.

Our measurements show that more than half of all wind turbines equipped with iSpin have significant yaw misalignment.
On average you can expect a 2% production increase from your wind farm by applying iSpin.


If you want to learn more click here for our Knowledge centre

iSpin is quick to install and easy to handle (read more)

The three ultrasonic sensors are permanently installed at the wind turbine spinner.

  • The whole system is easy and quick to install from within the spinner.
  • All data collected with iSpin is transferred through mobile network or the existing turbine web interface to us. We will analyse and send regular reports and potential alerts to you. Yaw misalignment is corrected using standard methods.
  • Direct SCADA connection of iSpin is also possible on request.
The perfect fit for all wind turbine models (read more)
iSpin consists of three specially designed ultrasonic wind sensors installed at the spinner. Here the wind is only influenced by the induction effect (slowing of the wind) caused by the turning rotor and its passage over the spinner.

Both these effects are predictable and can easily be corrected for e.g. using LiDAR or met mast calibration tools.

ROMO Wind has built a calibration factor database for the most common wind turbine models on the market.

The iSpin measurement principle is easy (read more)

The measurement principle of the spinner anemometer is very simple and it's illustrated in the figure below, where the three iSpin sensors are installed on the wind turbine spinner. If the rotor is placed correctly in the relation to the wind – that is, perpendicular to the wind direction – each sensor will produce the same wind speed measurement throughout the entire rotation.

But if the wind hits the rotor from a skewed angle (i.e. a yaw misalignment or other flow inclination), each sensor will measure cyclically varying wind speeds as the spinner rotates, because the wind is accelerated or decelerated over the spinner surface.

The amplitude of this cyclical wind speed variation
is proportionally related to the flow inclination angle, which therefore can be calculated.

This video demonstrates the advantages of wind measurement at the spinner, and how iSpin technology works

Key findings

The iSpin technology can measure parameters which until now have been difficult or impossible to measure with the current wind measurement equipment for wind turbines which has led to yaw misalignment and therefore a loss of production.

ROMO Wind distinguishes between static – or average – yaw misalignments and dynamic yaw misalignments. The latter is the standard deviation on the static yaw misalignment.

Conventional anemometers mounted behind the rotor on the wind turbine nacelle housing lead to inadequacy of data, because they measure the wind after it already passed through, where it is disturbed by the rotor, which makes accurate wind measurement impossible.

The turbulences created by the rotor and the wind flowing around the nacelle is unpredictable, making reliable performance monitoring and creation of power curves almost impossible, which is why it cannot be fully corrected.
This leads to the fundamental dilemma of yaw misalignment and significant production loss, which is why iSpin measures the wind in front of the spinner, where it hits the turbine first.

Persistent (average)  yaw misalignment

Yaw misalignment in degrees

<2° 2-4° 4-6° 6-8° 8-10° 10-12° 12-14° 14-16° 16-18° 18-20° >20°

Number of WTGs (total: 263)

60 67 39 35 21 14 8 6 7 3 3

Percentage of WTGs

23% 25% 15% 13% 8% 5% 3% 2% 3% 1% 1%
~48% ~28% ~24%

Static yaw misalignments are very frequent: ROMO Wind’s measurements on a large number of randomly selected wind turbines show that more than half of all wind turbines demonstrate a significant static (average) yaw misalignments.

The correlation between nacelle misalignment and loss of production is demonstrated in the table below. The results are proven by DNV GL calculations and the ROMO Wind test series. This statistic is updated regularly.


The high prevalence of yaw misalignments is of course not the result of the turbine manufacturers or service teams doing a bad job on the wind turbines. The key reason is that the standard equipment on wind turbines today cannot detect yaw misalignments. The technologies for detecting these problems only became commercially available in recent years – not least because of the iSpin technology.

There seem to be three main reasons why turbines may present yaw misalignments:

  1. Wind direction sensor issues
    If the wind sensor is mounted incorrectly by even a few millimetres, it will have severe consequences on the alignment
  2. Wind farm site conditions
    The off-set defined by the turbine manufacturer has not been adjusted to the installation site’s local conditions, causing a potentially large static yaw misalignment
  3.  New disturbances of the wind flow over the nacelle roof
    If the nacelle sensors are moved to another position on the nacelle roof or other equipment is mounted on the roof (e.g. aviation lights, nacelle LiDARs, etc.), they can severely affect the wind flow around the nacelle, having a negative impact on the function and calibration of the nacelle wind sensor measurements and hence on the turbine control.

Below: An example of the necessity of an accurate adjustment of wind sensors.


For further details and background documents please visit our Knowledge centre.

Knowledge centre

Welcome to the ROMO Wind Knowledge centre.
Here you will find detailed information on wind turbine optimisation, the importance of wind data accuracy and the iSpin spinner anemometer technology. We are pleased to share with you recent scientific research publications and other third party publications as well as ROMO Wind memos and brochures.

Just click on a button to learn more about the according topic.

If you do not find what you are looking for, please do not hesitate to contact us for help at and we will be glad to answer your questions.

Benefit from a win-win partnership with ROMO Wind

Every wind turbine should tap its full production potential.
To enable as many operators as possible to benefit from accurate iSpin data, we are leasing iSpin systems for a fixed monthly service fee.

In return you get installation and calibration, data collection, regular reports, analysis and alerts, and service and maintenance of iSpin. The best thing is that the additional yield, which can be generated by correcting yaw misalignment, can more than cover the service fee.

ROMO Wind offers a no-hassle solution.
Choose the iSpin offer that fits your needs or contact us for an individual solution:


Prevent yaw misalignment

iSpin Basic assures productivity thanks to permanent measuring and monitoring of yaw misalignment, which is not possible with any other current wind measurement method. In our experience correction of yaw misalignments on average leads to 2% more production from a wind farm. Permanent monitoring is necessary as yaw misalignments may often recur.


Improve your wind farm operation

As well as delivering all the benefits of iSpin Basic, iSpin Advanced also provides you with exact 360 degree wind measurement data, turbulence intensity insights and flow inclination data. This will help you to protect your turbines and, when combined with power measurement data, to optimise your operations by monitoring the power curve. It can also be used for repowering or wind farm expansion planning.


Full insight for full performance

In addition to the iSpin Advanced benefits, iSpin Advanced Plus offers you permanent, relative power curve monitoring – for total transparency and efficiency checks on your turbine at any time. Based on your time-synchronised power measurement data we will provide you with comprehensive and accurate information about the turbine performance.

For an individual offer or more information contact us at or get in touch with your local sales person.