T70P for Solar Farm Spraying: A Field Case Study
T70P for Solar Farm Spraying: A Field Case Study
META: Learn how the Agras T70P transforms solar farm spraying in complex terrain with RTK precision, optimized swath width, and drift control. Case study inside.
TL;DR
- The Agras T70P solved persistent spray drift and coverage gaps across a 47-hectare mountainous solar installation in southern Spain
- RTK fix rates above 99.2% enabled centimeter precision navigation between panel rows on slopes exceeding 18 degrees
- Nozzle calibration combined with the T70P's intelligent flow system reduced chemical waste by 34% compared to our previous ground-based approach
- The drone's IPX6K-rated airframe handled early morning dew and sudden rain without operational downtime
The Problem: Solar Farms Don't Stay Clean on Their Own
Solar panel efficiency drops by 15–25% when biological fouling, lichen, and weed encroachment go unchecked. Manual cleaning crews with pressure washers handle flat rooftop installations fine—but a sprawling solar farm cut into terraced hillsides across complex terrain? That's a different challenge entirely. This case study breaks down exactly how I deployed the Agras T70P to maintain a difficult solar installation, what went wrong with previous methods, and the specific configuration that finally delivered consistent results.
My name is Marcus Rodriguez. I consult on agricultural and industrial drone operations across southern Europe and North Africa. Over the past decade, I've managed spray programs for vineyards, olive groves, and—increasingly—large-scale photovoltaic installations. The project I'm detailing here changed how I approach every solar farm contract.
Background: The Solana Ridge Installation
In early 2023, a renewable energy operator contracted me to develop a vegetation management and panel cleaning protocol for their Solana Ridge facility—47 hectares of bifacial solar panels installed on terraced slopes outside Málaga, Spain.
Site Challenges
- Terrain grade: Slopes ranging from 8 to 22 degrees across six terraced sections
- Panel row spacing: Inconsistent gaps between 2.1 and 3.4 meters
- Vegetation: Fast-growing Mediterranean scrub, grasses, and seasonal wildflowers encroaching panel bases
- Access: No viable path for conventional spray vehicles on upper terraces
- Environmental sensitivity: Adjacent protected watershed requiring zero chemical runoff
Previous contractors had attempted ground-based spraying with backpack units and an ATV-mounted boom sprayer. The results were poor. Crew members struggled on steep grades, application rates varied wildly, and the ATV couldn't physically reach three of the six terrace levels. Spray drift from the boom setup deposited herbicide on panel surfaces, leaving residue that required additional cleaning passes.
The operator was spending nearly double their projected maintenance budget and still seeing efficiency losses from unchecked vegetation.
Why the Agras T70P Was the Right Platform
I'd previously used mid-range agricultural drones for vineyard work, but this project demanded a platform with specific capabilities that most units simply don't offer.
Payload and Tank Capacity
The T70P carries up to 40 kg of liquid payload in its dual tanks. For a site this size, payload matters—every return trip to refill burns operational time. With the T70P, I completed full terrace sections on single tank loads, cutting total flight cycles by 28% compared to my modeling with smaller-capacity drones.
RTK Precision in Complex Terrain
This is where the T70P earned its place on every future contract. The drone's RTK positioning system maintained a fix rate above 99.2% throughout operations—even on the steepest sections where GPS multipath interference from metal panel frames typically degrades accuracy.
That centimeter precision allowed me to program flight paths that threaded between panel rows with consistent 1.5-meter buffer zones on each side. No overspray on panels. No missed strips between rows.
Expert Insight: When flying RTK missions near solar panels, set your base station on the highest point of the site with clear sky view. Metal panel frames create multipath interference that degrades fix rates if your base station is positioned at ground level between rows. I placed mine on a concrete equipment pad at the terrace summit and maintained 99.2–99.7% fix rates across all sections.
Intelligent Nozzle Calibration and Swath Width
The T70P's variable-rate spray system adjusts output based on flight speed and altitude in real time. I configured a swath width of 6.5 meters for the wider terrace sections and narrowed it to 3.8 meters for tight row work.
Key nozzle calibration parameters I used:
- Nozzle type: XR110-02 flat fan tips for vegetation management passes
- Droplet size: 250–350 microns (medium classification) to minimize spray drift on exposed slopes
- Flow rate: 2.4 L/min per nozzle at operational speed
- Flight altitude: 2.5 meters above canopy for vegetation, 3.2 meters for broader weed suppression passes
This calibration produced coverage uniformity above 92% as measured by water-sensitive paper placed across test grids—a significant improvement over the 61–74% uniformity the previous ATV boom system achieved.
Multispectral Integration: Seeing What Eyes Miss
Before spraying, I flew multispectral survey missions to generate NDVI maps of the entire site. This identified vegetation density hotspots and—unexpectedly—revealed three panel clusters with anomalous thermal signatures suggesting electrical faults unrelated to vegetation.
The operator's maintenance team confirmed two faulty junction boxes and a damaged bypass diode from those flagged zones. That single multispectral pass saved them an estimated service call and prevented potential fire risk.
For the spray program, NDVI data allowed me to create variable-rate prescription maps. Dense vegetation zones received full application rates while sparse areas got 40% reduced rates, cutting total chemical usage by 34% across the project.
Pro Tip: Always fly your multispectral survey at least 48 hours before your spray mission. This gives you time to process NDVI maps, build prescription layers, and verify them against ground-truth observations. Rushing this step leads to over-application in areas that don't need it and under-application where it matters most.
Operational Performance: By the Numbers
| Metric | Ground Crew (Previous) | ATV Boom Sprayer | Agras T70P |
|---|---|---|---|
| Daily coverage | 3.2 hectares | 6.8 hectares | 14.5 hectares |
| Coverage uniformity | 58–71% | 61–74% | 92–96% |
| Chemical usage per hectare | 4.2 L | 3.8 L | 2.5 L |
| Accessible terrace sections | 6 of 6 (slow) | 3 of 6 | 6 of 6 |
| Panel overspray incidents | 12 per session | 8 per session | 0 |
| Staff required | 4 | 2 + driver | 1 pilot + 1 observer |
| Positioning accuracy | N/A | N/A | ±2 cm (RTK) |
| Weather resilience rating | Low | Moderate | IPX6K rated |
The IPX6K rating deserves special mention. Mediterranean mornings on these hillsides bring heavy dew and occasional fog. On two occasions, unexpected rain moved in during operations. The T70P continued flying without hesitation. Previous drone platforms I've used required immediate grounding in light rain, costing hours of productive flight time.
Common Mistakes to Avoid
1. Ignoring wind gradients on terraced terrain. Wind speed at the base of a terrace can differ by 3–5 km/h from the top. I measured wind at three elevation points before each session and adjusted spray drift compensation parameters accordingly. Flying a single wind reading across all terraces guarantees uneven application.
2. Using the same nozzle configuration for cleaning and vegetation management. Panel cleaning (typically deionized water or mild surfactant) requires finer droplets and lower pressure than herbicide application. Switching between tasks without recalibrating nozzle tips, droplet size, and flow rate leads to either wasted chemical or ineffective cleaning.
3. Setting swath width too aggressively for narrow row spacing. It's tempting to maximize swath width to finish faster. On this site, exceeding 4.0 meters in the tightest row sections caused edge-of-swath drift onto panel surfaces. Match your swath width to the narrowest gap you'll fly, then create separate mission profiles for wider sections.
4. Skipping the RTK base station survey. A quick autonomous base station setup introduces 5–15 cm of positional uncertainty. For solar farm work where you're flying between fixed structures, take the extra 10 minutes to survey your base station point properly. The centimeter precision difference prevents collision risk and overspray.
5. Neglecting post-mission nozzle inspection. Herbicide residue and mineral buildup from hard water sources clog nozzle tips gradually. After every three flight cycles, I pull and inspect each tip under magnification. A partially blocked nozzle degrades your carefully planned coverage uniformity without any warning in the telemetry.
Frequently Asked Questions
Can the Agras T70P handle both vegetation spraying and panel cleaning on the same site?
Yes, but not in the same mission. You'll need to swap nozzle tips, flush the tank system thoroughly, and load a different mission profile with adjusted altitude, speed, and flow rate parameters. I typically dedicate full mornings to one task and afternoons to the other, with a 30-minute changeover between configurations. The T70P's quick-disconnect nozzle system makes this practical in the field.
How does RTK performance hold up near large metal structures like solar panel arrays?
Better than expected—with proper base station placement. The T70P's multi-constellation GNSS receiver (GPS, GLONASS, Galileo, BeiDou) handles multipath interference from metal frames effectively. During this project, I logged over 126 flight hours near panel arrays and recorded RTK fix rate drops below 98% only twice, both during a period of poor satellite geometry that affected all receivers regardless of environment. Positioning the base station above the panel plane eliminates most multipath issues.
What's the maximum slope angle the T70P can safely operate on for terrain-following missions?
The T70P's terrain-following radar handles slopes up to approximately 25 degrees reliably. On the Solana Ridge project, I flew sections at 22 degrees without terrain-following errors. Beyond 25 degrees, I recommend breaking the slope into shorter mission segments with manual altitude checkpoints rather than relying entirely on automated terrain following. The centimeter precision of RTK positioning remains stable regardless of slope angle—it's the terrain-following sensor response time that becomes the limiting factor on very steep grades.
Final Thoughts from the Field
The Solana Ridge project ran for six operational days. By the end, all 47 hectares had received precisely mapped vegetation treatment with zero panel overspray incidents, and the operator had NDVI baseline data for ongoing monitoring. Their quarterly maintenance costs dropped, and panel efficiency recovered by an estimated 11% in the treated sections within 60 days.
The Agras T70P wasn't just an upgrade from ground-based methods—it made this particular project possible. Three of those six terraces were functionally unreachable by any vehicle, and manual crews would have needed weeks to cover what the T70P handled in days. For solar farm operators dealing with complex terrain, this platform removes the compromise between precision and coverage speed.
Ready for your own Agras T70P? Contact our team for expert consultation.