Publications

While wind Lidars like the ZX 300 are widely known for their role in the wind energy sector, they’re also tackling a other world challenges - namely methane emissions.

In partnership with TotalEnergies, our wind Lidar is being used in a whole new way: to provide the precise wind data needed for accurate methane monitoring. Why does that matter? Because methane is over 25 times more potent than CO₂ at trapping heat in our atmosphere.

As the shift towards renewable energy gains momentum, innovative hybrid development projects are emerging to maximise efficiency, reliability, and cost-effectiveness. ZX Measurement Services looks at how integrating wind and solar energy assessments can enhance output and stability, exploring essential measurement strategies for optimising these systems.

The global wind energy sector continues to grow at an unprecedented rate, necessitating the adoption of advanced, reliable, versatile and appropriate wind measurement tools. Lidar technology has emerged as an essential solution in this evolving landscape,

This white paper explores the widespread adoption of Wind Lidars, providing evidence that from wind resource assessment to operational monitoring, Wind Lidars can be a trusted tool used globally.

PO.099 WindEurope Technical Workshop, Dublin 2024

Continuous Wave (CW) wind Lidar performance over a 10-year lifetime has been repeatedly demonstrated at the UK’s Remote Sensing Test Site. CW Lidars are subjected to, and suitably thrive in the range of climatic conditions experienced around the world, onshore and offshore, throughout over a decade of operational life.

PO.096 WindEurope Technology Workshop, Dublin 2024

High data availability is critical for wind measurement campaigns. ‘Gaps’ can occur in any measurement sensor data for a variety of reasons hence, in this study, a  range of gap-filling methods were investigated. CW Wind Lidars demonstrate extremely high levels of availability that can be further enhanced with an industry-standard power-law shear extrapolation.

PO.108 WindEurope Technical Workshop, Dublin 2024

Embracing Machine Learning to further maximise the accuracy and availability of wind speed data for Continuous Wave Lidar Systems

PO.181 - WindEurope Conference, Bilbao 2024

An IEC- compliant assessment of ZX TM nacelle-mounted lidar measurements has been reported by DNV (1), following the IEC 61400-5-3 standard (2). Here we present a thorough case study deriving uncertainties for hub-height horizontal wind-speed (HWS) measurements made by a ZX TM on a 3 MW turbine in central USA.

PO.187 - WindEurope Conference, Bilbao 2024

We demonstrate load reduction using lidar assisted control using a feedforward/feedback controller and a simplified lidar system. This solution was retro-fitted to a commercially operating wind turbine. Complex aeroelastic wind turbine models were unavailable and the through life cost of the lidar control system was targeted.
Tower fore-aft bending and blade flap edgewise moments were significantly and safely reduced without negative effects on AEP. The methods and technology applied provide an opportunity to reduce the LCOE of current and future turbines.

In November 2014 we asked the industry ‘can we bank on wind Lidar’? Can we use it to provide quantitative data for the annual energy prediction
of a wind farm, allowing developers to raise or ratify the necessary finance to progress and construct full-scale developments? Today, in 2022, that
question has not only been answered, spoiler alert: it’s a ‘yes’, but the industry is now not just ‘banking’ on it, it is ‘relying’ on it.

The role of lidar within wind measurement campaigns is routinely documented in wind energy publications, conferences, and in important, fundamental academic research. Often, the focus is on the types of and use of measurements/data that wind lidars offer. Sometimes overlooked is the ability to deploy lidar at speed; not only once on site, practically, due to the sensor itself being remote, i.e. at ground level, from the target, i.e. the wind, but actually often without the need for any planning permission whatsoever.

Lidar unit #106, nicknamed Eunice may have started her life in the Malvern Hills but for the past 15 years she has been understanding the wind across the complex terrain of the Greek Islands.

This work outlines, through a number of case studies, a cost-effective approach for verifying the performance of a met mast using a continuous wave lidar, ZephIR 300, ensuring that calibration of the data is both accurate and problem-free. Once deployed for mast verification, ZephIR 300 also provides the ability to validate the wind shear model used for a particular deployment, demonstrating a further reduction in the uncertainty associated with the extrapolation of mast data within the wind resource campaign.

In this work, CFD conversion of measurements taken by a Continuous Wave lidar, ZephIR 300, in varying terrain types and complexity is demonstrated, highlighting a transparent methodology that is capable of producing bankable measurements in terrain not considered to be simple.

This report presents the updated results from over 240 ZephIR 300s validated against a tall IEC compliant meteorological mast. Since 2010, ZephIR have operated the first UK remote sensing test site. With the increasing number of ZephIR 300s being validated against this mast, statistical analysis of validation results robustly shows the repeatability and stability of the calibration of ZephIR 300s.

A large dataset from a ZephIR 300 has been independently analysed by a team from Loughborough University. The performance has been assessed in comparison to a 91m met mast; wind speed, direction, TI and atmospheric stability have all been examined, and the conclusion is that the lidar is capable of measuring the wind resource to at least the same standard as a met mast.

The paper examines the potential for CW lidar to measure turbulence characteristics from both ground-based and turbine-mounted lidar. A new method has been applied for the second of these cases, in which the instantaneous Doppler spectrum is used to derive a value of turbulence that corresponds closely to that measured by a cup. In doing so it avoids some of the well-known difficulties caused by spatial averaging and contamination by vertical components.

Can you use wind lidar to provide quantitative data for the annual energy prediction (P50, P75 and P90) of a modern scale wind farm, allowing developers to raise the necessary finance to progress and construct full-scale developments? This paper demonstrates ZephIR's acceptance across onshore benign sites, onshore complex sites, offshore on fixed platforms and offshore on floating platforms.

This paper demonstrates by simulations, controlled experimental studies and the results of field deployments that the effect of motion on ZephIR performance is insignificant and easily compensated, largely due to the high-resolution, fast data rates and multiple viewing angles enabled by the very high carrier to noise ratio unique to continuous wave wind lidars, such as ZephIR. Stability of ZephIR performance is therefore confirmed for cases where lidar is subject to extreme motion, namely mounted on a floating offshore platform or on a wind turbine nacelle.

Two ground-based ZephIR 300 lidars have been classified at the UK Remote Sensor Test Site at Pershore according to the procedure described in Annex L of the IEC draft guidelines. The mean accuracy classes for these units cover the ranges 3.0% – 3.8% for heights between 20 m and 91 m, after accounting for correlations between the environmental parameters. These values correspond to mean standard uncertainties of 1.7% - 2.2%.

The increasing number of ZephIR deployments in more extreme environments demonstrate ZephIR 300’s ability to retain high availability (>90%) in very cold conditions and in extremely clear atmospheres. This report covers the theoretical limits of CW lidar sensitivity with range, and aerosol concentration and presents results from a long (>12 months) continuous ZephIR 300 campaign at high latitude exhibiting extremes in temperature and air clarity.

This report presents the results from over 170 ZephIR 300s validated against a tall IEC compliant meteorological mast. Since 2010, ZephIR have operated the first UK remote sensing test site. With the increasing number of ZephIR 300s being validated against this mast, statistical analysis of validation results robustly shows the repeatability and stability of the calibration of ZephIR 300s.

This report demonstrates the performance of a ZephIR Continuous Wave (CW) lidar over a period of 40 months continual operation. It examines the performance before and after the 40 month operational deployment, during which time no maintenance or servicing has been conducted on the ZephIR.

A ZephIR DM lidar was mounted on the nacelle of a large turbine, adjacent to a fixed mast and a second ground-based vertically profiling ZephIR DM. The wind speed and turbine power curve measurements from both ZDM lidars were in very close agreement with each other and with the reference mast, showing very little bias or scatter.

An investigation of ground-based ZephIR 300 units at the Pershore test site shows that the horizontal wind speed is negligibly affected by a static tilt of the lidar up to 10 degrees. The data are also used to demonstrate the accurate measurement of inflow angle by ZephIR 300.

Measurements by a ZephIR DM lidar mounted on the nacelle of a test turbine at Riso DTU have been validated against a met mast, and have been used to derive a rotor-equivalent power curve in accordance with the latest draft of the IEC guidelines.

Analysis has been carried out on data from ZephIR 300 units deployed at the Pershore test site, in accordance with the classification scheme for remote sensing devices proposed in the latest IEC guidelines.

A major use of turbulence data in a site assessment campaign is to inform the selection of wind turbine type. Analysis of turbulence data from ground-based ZephIR 300 units has been used to investigate a hypothetical wind farm layout; the overall choice of turbine type is unaffected by whether lidar or mast data is used.

Lidar can offer significant financial savings in comparison to traditional methods of anemometry for resource assessment, partly through reduction of uncertainty.

March 2013 saw the tenth anniversary of the first commercial lidar deployment for wind energy applications – and while it is now commonplace to see wind lidars (such as ZephIR 300 and those that followed) in wind energy resource assessments, it was actually a turbine-mounted application for which the ZephIR technology was first deployed.

Nacelle-mounted lidar offers an exciting alternative to conventional methods for measurement of turbine power curves.

Measurement of turbulence intensity (TI) at hub height plays a role in wind resource assessment through the estimation of energy losses due to turbine wakes and is also a key component of site classification and turbine selection studies.

The results in this paper demonstrate that the exceptional sensitivity and high data rates of CW wind lidars allows high quality wind measurement to be carried out in many buoy-mounted applications without motion compensation.

This paper describes recent advances in the calibration and performance verification of ZephIR 300 lidar units.

This paper contains a description of a complex flow conversion technique that converts raw lidar line-of-sight velocity data into precise, unbiased measurements of horizontal wind speed on hilly and mountainous sites.

Results are presented of a comparison of TI measurements from several ZephIR 300 units against an IEC compliant 91.5m anemometer mast. The data were collected over more than 5000 hours of operation at Natural Power’s dedicated lidar and sodar test site.

A modified ZephIR unit has provided the first successful demonstration of lidar in a wind tunnel. Very good correlation with reference measurements was obtained across the full speed range of 5-75 m/s.

Risø DTU has carried out an evaluation test of the new ZephIR 300 (Z300) wind lidar over a 5 week period in 2011. The full report and data summary is available.

In 2005 ZephIR, the first wind lidar system for the wind industry, became commercially available founded on decades of lidar expertise within QinetiQ, a UK research and development laboratory.

The horizontal wind speed measured lidar can be subject to differences in comparison to that measured by cup anemometers when flow is non-uniform across the lidar measurement disk.

This paper reports the results of a measurement campaign in which wind turbine power curves have been evaluated using a ZephIR laser anemometer. The study was carried out in collaboration with EDF Energies Nouvelles.

Risø DTU carried out a validation test of ZephIR lidar 145 in the period 22 Oct to 17 November 2009. The lidar was placed 40m north of the meteorological tower at Høvsøre Test Station for Large Wind Turbines, Denmark.

This report presents the post processing and analysis of data sets from a ZephIR laser anemometer and an anemometer mast equipped with cup and vane instruments co-located in Mason City, Iowa.

It has been shown many times that the mean horizontal wind speed measured by a lidar over flat terrain compares very well with that measured by a cup anemometer. But can a lidar measure turbulence? This report investigates the case of a continuous wave, conically scanning Zephir lidar.

Offshore wind farm projects that require pre-construction financing cannot afford to rely on proxy data that are recorded at distant locations to characterize key design parameters present at the proposed site.

The paper used a ZephIR for several studies and reaches a conclusion that lidar anemometry can provide consistent estimates of mean flow tilt angles also for the very turbulent forest flow. In general, the results from all sites pointed to the high accuracy of the lidar.

Laser anemometry was first developed in the 1970s using gas lasers, and until recently has been used primarily as a research tool. The ZephIR laser anemometer can be rapidly deployed, configured and redeployed, with both on-board data storage and wireless data transmission.

WAsP Engineering was used to provide a correction to ZephIR lidar data obtained in complex terrain that accounts for the non-uniform flow across the scan disk.

In February 2006 WINDTEST Kaiser-Wilhelm-Koog GmbH (WINDTEST) was ordered by TALISMAN ENERGY (Limited) UK to assess the offshore performance of a LiDAR system of type QinetiQ/ZephIR relative to classical measurements at an offshore meteorological mast on the German wind energy research platform FINO-1 located in the German North Sea sector.

The paper describes the first investigation in which lidar units are installed in the blades of a large wind turbine. The data showed potential for real-time evaluation of angle of attack, and the impact of shear was observed as the blade traces out the rotor disc.

A modified ZephIR lidar was mounted in the spinner of a large turbine and incorporating a novel two-dimensional scanner. The data provide unprecedented detail of the incoming flow pattern, allowing investigation of phenomena such as wakes and natural turbulence.

The feasibility of upwind observations via a spinner-mounted wind lidar was demonstrated for the first time during this experiment. A ZephIR lidar was installed in the rotating spinner of a MW-sized turbine for several months during 2009.

The experiment was conducted with a modified ZephIR to test the simple hypothesis that the wake deficit is advected passively by the larger-than-rotor-size eddies in the atmospheric flow, and that the wake at the same time widens gradually, primarily because of mixing caused by small-scale atmospheric eddies.