FaunaScan MV2

Collision Risk Management and Long Term Monitoring

Bird Migration

Bird migration happens mainly during nighttime and is mostly homogeneous over a larger area. Measurement of bird migration at one specific location is usually representative for an area of several kilometers around this location. Depending on the location, a few high-intensity migration nights during spring and autumn make up the majority of bird migration. Curtailing (stopping) the wind-park during these nights protects the majority of birds from collisions with wind turbines. FaunaScan MV2 measures bird migration in real-time and protects birds with the integrated collision risk management algorithm.

Local Bat Activity

FaunaScan MV2 detects local as well as migrating bats and distinguishes them reliably from birds and insects. As full wind park coverage for detection and classification of bats is difficult to achieve, strategically placed FaunaScan MV2 can inform and curtail a whole wind park even with differences in local abundance levels. FaunaScan MV2 herewith overcomes the shortcomings of microphones (limited range, dependency on echolocation calls, susceptibility to weather conditions), traditional radar systems (unreliable detection inside a wind park due to interferences from rotor blades, insufficient distinction between bats and birds) and infra-red camera systems (limited range, limited by visibility and environmental conditions).

Protecting Migrating Birds

 Calibrated Bird Migration Measurements

Bird migration happens predominantly at night and can be concentrated on a few high-intensity migration nights in autumn and spring. Identifying these bird migration nights early on with the real time radar measurements enables an effective and economical curtailment of wind parks. Depending on the location, the majority of birds can be protected with only one percent of power loss.

The scientific unit for measuring bird migration intensity is Migration Traffic Rate (MTR) that measures the number of birds passing through a reference area of 1 km width per hour. The height of the reference area is defined according to the use case, for active curtailment of wind parks this is the interval from the lower to the upper rotor passage. In flat topography, bird migration is homogeneous over distances of several kilometres. This means that one or two radars are representative of an entire wind farm.

Real-Time Radar Data

X-band radar data is acquired 24/7 independent of visibility conditions. Exactly as reliable during night-time as during daytime data is acquired when most bird migration happens. As opposed to any optical system, FaunaScan MV2 sees right through fog and measures bird migration when collisions are most likely. By detecting the smallest birds reliable at 1 km altitude there is no doubt that the relevant altitude interval for wind parks (lower to upper rotor passage) is measured reliably. 

Micro-Doppler signatures ensure that clutter can be rejected with highest confidence as biological activity is clearly detectable in the signatures. Moreover, insects can be reliably distinguished from birds by means of Micro-Doppler signatures, accurate size estimation and extracted shape parameters. Erroneous curtailments due to insect abundances can be avoided due to unparalleled classification performance.

Collision Risk Management Algorithm

The main factor for collision risks of birds with wind turbines is the presence of the former. Measuring accurate bird migration quantities allows to protect the majority of birds with exact curtailments during bird migration nights. Other environmental factors like visibility conditions play an important role in collision risk assessment. Such environmental factors can be incorporated in automatic real-time curtailment decisions. The illustration below shows the migration intensity over several days. Curtailment thresholds have been set lower during nighttime to account for an increased collision risk during poor visibility conditions. In the case of foggy conditions, the threshold has been set even lower.

Environmental and Operational Inputs

Environmental as well as operational inputs can be incorporated in the collision risk assessment algorithm and subsequent automatic real-time curtailment decisions. Additional sensors can be connected over Scada or other communication protocols. Wind park operational data like wind-speeds or power production could also be considered for curtailment decisions to account for both bird protection as well as energy losses. 

Configurable Algorithm for Regulatory Compliance

A flexible and configurable collision risk assessment algorithm ensures conformity with regulatory demands. Bespoke curtailment algorithms and communication interfaces allow to incorporate additional sensor data. With a configurable algorithm and interface, conformance with changing regulatory requirements remain manageable and cost efficient.

Protecting Migrating Bats

Detecting migrating bats is difficult with traditional sensors as they can migrate at high altitudes and echolocation calls could be less frequent at those higher altitudes. FaunaScan MV2 is uniquely positioned for migrating bat protection by detecting the smallest bats up to 1 km altitude independent of any echolocation calls and distinguishing them reliably from birds and insects.

The illustration below shows bat activity during nighttime with a lot of activity during the early night and some activity throughout. The bat activity during the early night is concentrated to lower altitudes of around 0-300 meters. The directional profile shows that these bats are probably foraging due to the omnidirectional distribution. The bat activity throughout the night is concentrated around 800 meters and is directional indicating that those are migrating bats. 

Reliable bat data allows to optimize curtailments to time periods where bats are effectively present at rotor altitudes. 

Curtailment for migrating bats can be realized with similar evidence-based curtailments as for bird migration. Based on traffic rates in the relevant altitude interval a threshold can be set for wind parks curtailment. Curtailments for just bats alone or for both birds and bats with different thresholds and collision risk management can be configured.

Protecting Local Bats

Depending on the local circumstances one or more FaunaScan MV2 systems can accurately measure local activity. The illustration below shows a network of five radars in a wind park with data for different activities: migration (left), general bat abundance (middle) and site-specific effects (right). For the first two cases one radar is representative for the wind park.  In the last case on the right there is a site-specific effect whereas either a micro-siting study or a network of radars can measure and model local behaviour. Distribution models for different species groups can then be measured to generate essential biological insights as well as enable efficient and targeted curtailment.

The radar network approach circumvents the limitations of 360° radars within wind parks (the rotating blades generate huge disturbances for radar) while still taking advantage of radar technology (works day and night even in bad visibility conditions and sees even the smallest birds up to high altitudes) and specifically the species group identification possibilities of FaunaScan MV2.

Species Protection

Small or nocturnal species are inherently difficult to protect as traditional sensors cannot detect them at large distances or distinguish them from other species. FaunaScan MV2 offers a unique opportunity by training the classifier for local species. Success of course depends on the species that is to be protected as well as the presence of other similar species. The illustration below shows two different bat species with clearly distinct Micro-Doppler signatures.

For reference data collection we offer our camera system AeroecologyCam AC1, ultrasonic microphones or other third-party sensors could also be integrated.

For nighttime detections, the AC1 camera system can be equipped with infrared spotlights and setup adjacent to the camera system. Based on track matching between the systems, reference data can then be collected (at lower altitudes) for training of the MV2 classifier which then classifies the protected species at higher altitudes and all visibility conditions.

Reference data collected by ultrasonic microphones for bat species with echolocation calls visible as red dashed vertical lines. Due to the synchronization of wing beat angle and echolocation calls unambiguous matches between microphone and radar data can be collected.