Drones For Solar Panel Inspections

• Drones are a powerful tool for solar panel inspections, collecting data more than 50x faster than manual methods.

• Solar panel installations have grown massively - up by 81% in 2019, compared to 2018. More installations mean more inspections.

• Harnessing the DJI ecosystem, the M300 RTK and H20T payload is a great solution, offering expanded flight time and thermal, zoom and wide-angle capabilities.

• The DJI M30T is also a suitable option, with its mix of power and portability.

• "Drones increase data quantity and quality and reduce costs and hazardous man-hours," says DJI.

Drones have become a vital tool for solar panel inspections, collecting data more than 50x faster than manual methods and improving safety by avoiding hazardous man-hours.

And the emergence of UAVs as the go-to tool for this type of work looks set to accelerate, as the trend towards adopting renewable energy is expected to grow massively in the coming years.

When it comes to integrating drones into your solar panel inspection workflows, DJI has a range of solutions; including the flagship M300 RTK platform and H20T payload, pictured below.

This combination offers long flight times, smart features to streamline and automate inspections, and thermal, zoom, and wide-angle capabilities - helping to increase daily productivity.

The M300 RTK has substantially improved fieldwork with its new functionalities. It has allowed us to increase daily productivity on the configuration of the plant, reaching up to 40 MWp per day of fieldwork.

Ignacio Bullon, CEO of solar panel inspection company Exanter

The DJI M30T is another ideal solution for thermography. In what is essentially a mini Matrice 300, it packs in many of the same performance capabilities but in a smaller frame. 

Meanwhile, another reliable solution is the DJI M200 Series, which can be integrated with a DJI Zenmuse XT2 thermal sensor and a DJI Zenmuse X5S RGB camera., while the Mavic 2 Enterprise Advanced packs a powerful thermal and visual sensor in a lightweight, portable and foldable frame. 

DJI Gold Partner heliguy™ sells the M300 RTK, M30T, Mavic 2 Enterprise Advanced and M200 Series platforms, and can support your enterprise drone program throughout its lifecycle. heliguy™ also offers the UK's largest drone rental service.

The benefits of using drones for solar panel inspections were explained during a webinar hosted by Eduardo Rodriguez, Enterprise Product Manager for DJI Europe.

He said: "Drones featuring thermal imaging payloads allow operators to perform a full solar farm operation in a matter of hours, compared to days using manual methods. They increase data quantity and quality and reduce costs."

Thermal imaging is vital for solar panel inspections.

A Look At The Market

Worldwide growth of photovoltaics (also known as solar PV) has been close to exponential between 1992 and 2018. During this period of time, photovoltaics (PV) has evolved from a niche market of small scale applications to a mainstream electricity source.

And this trend is not slowing down. In fact, an 81% growth is expected in 2019 across the 28 EU countries, jumping from 11.3 GW (gigawatt) installed in 2018 to 20.4 GW in 2019.

And with these countries having until 2020 to meet their binding national renewable targets, it is predicted that there will be a large investment in the PV market and, as such, the number of installations will continue to climb.

By 2023, for instance, Germany, Spain, France, Netherlands and Italy will generate more than 75% of all European photovoltaic energy, according to statistics provided during the DJI webinar.

A photovoltaic system employs solar modules, each comprising a number of solar cells, which generate electrical power. PV installations may be ground-mounted, rooftop mounted, wall-mounted or floating. The mount may be fixed, or use a solar tracker to follow the sun across the sky.

And guess what, all of these components need to be inspected for maintenance and to ensure your operations are running smoothly.

This is where drones for inspections come in.

Drones help to save time and maximise data collection.

Drones Versus Manual Methods

Solar panel inspections are already happening, but the vast majority are still performed manually, using hand-held thermal cameras.

A thermal camera can help identify manufacturing defects, cracks, faulty inter-connectors, defective bypass diodes and temporary shadowing.

Hand-held and manual inspections are fine, but this process is not as efficient as it could be. Fly forward the drone - which yields faster and more accurate data capture and helps to improve safety.

From hand-held inspections...

...to carrying out drone missions.

In a nutshell, here are some of the ways that drones are a superior inspection method compared to traditional/handheld techniques:

• Increase efficiency: Drones collect data more than 50x faster than manual methods. Solar farms are typically very large installations, so a drone equipped with an appropriate thermal camera can scan the site for defects much faster than using a thermal camera on the ground.

• Get better quantity & quality information: Efficiently identify issues manual processes might miss.

• Avoid hazardous man-hours: Conduct surveys and inspections without being exposed to potential danger.

• Reduce costs: Not only in inspection, but maintenance, equipment and potential shut downs.

• Store, track & distribute data: Manage data with a secure portal and convenient reporting.

When it comes to increasing efficiency and enhancing data capture, drones have major advantages. For instance, thanks to the sophisticated payloads they can carry, drones let solar panel inspectors obtain both thermal and RGB (visible light) data.

And while thermal imaging is crucial for solar panel inspections, RGB is essential to give a complete picture of what is happening on your site.

Drones are powerful tools for solar panel inspections.

During the webinar, Eduardo said: "With the use of drones, apart from increased efficiency and reduced costs, we can capture both thermal and RGB data and this is really, really relevant.

"By carrying out only thermal inspections, this could potentially lead to a false positive, which means we could misidentify non-electrical issues like soiling, shading or animal nesting, and you could be misled to thinking that these are electrical problems when they actually are not."

Drones can provide RGB and thermal data sets which helps you maximise your results and analysis.

He added: "Thermal and RGB data sets are also important when it comes to quantitative and qualitative analysis - both essential to understanding defects on solar panels.

"In terms of quantitative analysis, this refers to temperature data from every pixel on the thermal sensor. This is known as radiometric data, and this can be used to evaluate the impact of the defect.

"This is completely different from qualitative analysis. This refers to the data captured by the RGB sensor, as well as the post-analysed thermal data. It tells us which type of problem you have. It won't tell the impact of the problem - we get that from quantitative analysis - but it will tell us if there's an electrical problem or more of a shading/soiling problem."

A thermal inspection using a drone.

Increasing efficiency is crucial when it comes to inspecting solar panels. With weather conditions having to be almost perfect - dry, clear, little-to-no wind and the panels reaching a certain level of irradiance - there are often only a few hours in the day when checks/maintenance can be carried out. Therefore, a drone lets you capture this data quickly.

Using The DJI Eco-system

So, the case for carrying out drone inspections has been made. But which DJI aircraft is best suited for this type of work?

A look through the enterprise ecosystem picks out a number of candidates - the M300 RTK, M30T, M200 Series, and the Mavic 2 Enterprise Dual.

Out of these choices, the M300 RTK and M30T are quality solutions, but the other DJI drones mentioned are reliable options. Which one you choose will depend on your requirement and budget.

Solar Panel Inspection With The M300 RTK

The M300 RTK is DJI's flagship commercial drone and it has a range of functions and capabilities which make it the perfect choice for PV inspections.

Firstly, its flight performance helps to drive efficiencies, thanks to a maximum flight time of 55 minutes without payload, or 43 minutes with the H20T.

This endurance ensures that more data can be collected during a single flight.

The M300 RTK is also DJI's most robust aircraft to date, with an IP45 rating - exceeding the IP43 rating of the M200 Series V2 and V1 - and has an enhanced wind-speed resistance of 15m/s.

The drone benefits from hot-swappable batteries, enabling operators to switch them without restarting the aircraft - helping to reduce downtime.

It is also a highly versatile drone. The fact that it can interchange payloads means it can be used with a range of different sensors - including photogrammetry or LiDAR surveying cameras - making it a suitable aircraft for a variety of missions.

Introducing the H20T Payload

The M300 RTK can also carry up to three payloads, has a maximum payload weight of 2.7kg, and a maximum take-off weight of 9kg.

On the payload front, the drone can be integrated with the XT2 thermal camera, Z30 zoom camera, and third-party sensors through Payload SDK.

But the real highlight of the M300 RTK is the H20 camera series, engineered especially for this drone.

For PV inspections, the H20T is an ideal solution, as it comes with zoom, thermal, and wide-angle capabilities. It also has a laser rangefinder, but that function isn't really of use for checking solar panels.

The key specifications are:

• Thermal: 640 x 512px radiometric camera. Frame rate 30fps.

• 20MP Zoom: 23x hybrid optical zoom; 200x maximum zoom. Video resolution 4k/30fps.

• 12MP wide camera: Equivalent focal length 24mm; DFOV 82.9°.

According to IEC standards, you need at least a 640 x 480 thermal resolution to perform an effective thermal solar panel inspection. The H20T surpasses this.

The IEC also says that a 9MP camera is sufficient if you require RGB images to understand your thermal data. So again, the H20T fits the bill.

The H20T also allows operators to switch between camera views.

M300 RTK For Smart Inspection

The M300 RTK has a range of smart inspection features which streamlines and automates solar-panel inspections.

• Live Mission Recording: Record mission actions such as aircraft movement, gimbal orientation, photo shooting, and zoom level to create sample mission files for future automated inspections.

• AI Spot-Check (with the H20 Series): Automate routine inspections and capture consistent results every time. Onboard AI recognises the subject of interest and identifies it in subsequent automated missions to ensure consistent framing.

Using the M200 Series For PV Inspections

The DJI M300 RTK is a powerful enterprise drone, but if it isn't for you, there are other options available.

Solar Panel Inspection With The DJI M30 Series

Another stellar choice is the DJI M30T, part of the DJI M30 Series.

In what is a smaller version of the M300 RTK, the M30 has very similar performance capabilities, can fly for up to 41 minutes and even has an enhanced IP rating of IP55. 

Unlike the M300 RTK, the camera is fixed to the drone and is not interchangeable, but it has some impressive specs:

• Wide Camera: Equivalent Focal Length: 24 mm, DFOV: 84°; 12 MP 1/2'' CMOS Sensor; Video Resolution: 4K/30fps.

• Zoom Camera: 48 MP 1/2'' CMOS Sensor; 5x-16x Optical Zoom, 200x Max. Hybrid Zoom; Photo Resolution: 8K; Video Resolution: 4K/30fps.

• Thermal Imaging Camera: Equivalent Focal Length: 40 mm; Resolution: 640 x 512 or Infrared Image Super-resolution Mode: 1280 x 1024; Frame Rate: 30fps; Measurement Accuracy: ±2°C or ±2%.

• Laser Rangefinder: Range: 3 m - 1200 m; Accuracy: ±(0.2m+D×0.15%).

As for the size, the M30T is significantly smaller than the M300 RTK, making it easier to carry and transport: Particularly useful if your solar panels are located in areas which are difficult to reach.

RELATED ARTICLE: Find out how the M300 RTK and M30T compare in our camera comparison with side-by-side sample datasets

Solar Panel Inspection With The DJI M200 Series

While not as powerful or weather-resistant as the M300 RTK, its predecessors, the M200 Series V2, are still reliable, rugged, and capable aircraft for PV inspections.

RELATED ARTICLE: M300 RTK v M200 Series V2

Drones in the M200 Series V2 boast an IP43 rating and can carry quality payloads which allow you to access high-quality thermal and RGB data - namely the DJI Zenmuse XT2 and the DJI Zenmuse X5S.

A DJI M200 Series drone.

Focusing on the payloads, the XT2 is a robust dual-sensor thermal solution, with a 640 × 512 thermal resolution and a 12MP RGB camera.

A DJI Zenmuse XT2 camera integrated with a DJI M200 Series drone.

The XT2's capabilities surpass the 640 x 480 thermal resolution, and 9MP RGB thresholds set out by the IEC standards for effective solar panel inspections.

However, if you need to perform more detailed RGB inspections or you want to capture more precise orthomosaics, the 12MP sensor of the XT2 is not enough.

And this is where the X5S comes in, thanks to its incredibly powerful 20.8MP RGB camera. It also has a Micro 4/3 sensor and a dynamic range of 12.8 stops.

The DJI Zenmuse X5S mounted on top of an M200 Series drone.

Both payloads can be integrated with the M200 Series, however they can't be connected at the same time on the M210/M210 RTK models as they both connect to the gimbal number one port. (The M200 drone can only carry one payload).

While this means that you will need to conduct separate flights, it still provides an efficient solution and helps you capture quality thermal and RGB data quickly and efficiently.

Mavic 2 Enterprise Advanced In Solar Panel Inspections

Another alternative is the DJI Mavic 2 Enterprise Advanced.

This lightweight, foldable and extremely portable solution is able to capture visible and thermal data, and is a more cost-effective option than using the M200 Series V2 and M300 RTK and separate payloads. It is also more cost-effective than the M30 Series.

The Mavic 2 Enterprise Advanced is a powerful drone, and blows its predecessor - the Mavic 2 Enterprise Dual - out of the park. You can read a comparison article here.

The M2E Advanced packs a mightily impressive 640 x 512 px thermal sensor and can also capture 48MP visuals. The below image shows how the thermal resolution on the M2E Advanced enables far clearer images than the Dual.

For these reasons, the Mavic 2 Enterprise Advanced is an ideal drone for solar panel inspections.

PV Checks Using The M600 Pro

Another solution to throw into the mix is the DJI M600 Pro. This heavy-duty industrial drone, which can carry large payloads, is suited to very specific missions and might not be necessary for solar panel inspections. However, this tweet below shows that it can be used for solar panel inspections - especially on very large sites.

Conclusion

Solar panel installations are expected to rise throughout the UK and Europe over the coming years. A jump in installations means an increase in inspections. This bodes well for the drone industry.

After all, drones are a far more effective solution than traditional, hand-held manual techniques - helping inspection firms increase efficiency, capture incredibly accurate data and enhance safety.

When it comes to the DJI ecosystem, the M300 RTK drone and the H20T offers a comprehensive solution, while the M30T is a more portable version of the M300 - although not as versatile.

However, other drones in the DJI ecosystem, such as the M200 Series V2, Mavic 2 Enterprise Advanced and M600 Pro, can also be deployed for these missions.

To find out more about the drones and payloads mentioned in this article, or to discuss how heliguy™ can support, scale or start your enterprise drone program, contact us by sending us an email or giving us a call.