To obtain accurate and up to date information about site conditions for solar PV plant development, Solariss LLC has engaged local specialized survey company ITEG LLC to carry out professional drone survey of the site. Survey methodology, equipment used and results of survey campaign are described thoroughly below.
Drone survey – data capture and processing
A drone topographical survey is a survey method that uses unmanned aerial vehicles (UAV) equipped with various sensors to collect data about topography and physical features of given site. The collected data (photographs) are then processed through photogrammetry software to create detailed maps and 3D models of the site.
This type of survey is important for solar PV site assessment as it provides accurate and up-to-date information about the terrain, vegetation, and other physical features of the site. This information is crucial for the design and engineering of a solar PV system, as it allows to identify potential issues and optimize the layout of solar PV plant for maximum energy production.
By using a drone topographical survey, developers can save time and reduce costs compared to traditional ground-based survey methods. Additionally, drones can access areas that are difficult or impossible to survey with traditional methods, providing more comprehensive and accurate data.
The Kosuriq site and surrounding area was surveyed with UAV on 15.01.2023. Apart from UAV, Ground Control Points (GCP) have been placed to verify accuracy of UAV measurements.
Below are parameters of the UAV, sensor, capture parameters, processing, and output results.
Parameters of UAV, sensor, processing, and results.
| Drone (UAV) model: | WingtraOne GEN II with PPK |
| Camera: | DSC-RX1RM2, 35.000 x 23.345 mm, 48MP (RGB). |
| Ground Sampling Distance (GSD): | 2.99 cm / 1.18 in |
| Area covered: | 4.101 km2 / 410.1288 ha |
| Dataset: | 1,016 calibrated images |
| Photogrammetry processing: | Pix4D |
| Point Cloud Densification: | 329,220,602 |
| DSM and Orthomosaic Resolution: | 1 x GSD (2.99 [cm/pixel]) |
| Output Coordinate System: | KosovaRef01 |
Results of drone survey
The UAV survey and processing generated useful information about site, including:
- Aerial Images (Orthophotos)
- Digital Surface Model
- Digital Terrain Model
- Terrain Contours
The obtained data in conjunction with other geographic constrains are basis for identification of suitable sub zones for solar PV plant development within the property.
Aerial images – Orthophotos
A digital orthophoto is a computer-generated image of an aerial photograph in which displacements (distortions) caused by terrain relief and camera tilts have been removed. It combines the image characteristics of a photograph with the geometric qualities of a map.
Digital Surface Model
Digital Surface Models (DSM) are often confused with Digital Terrain Model (DTM). The main difference between the two models lies in the fact that the DSM generally takes into account all persistent objects on the ground (vegetation, buildings, and other artifacts) – while the DTM shows the development of the geodesic surface.
DTM sometimes called Digital Elevation Models (DEM) is a topographic model of the bare earth that can be manipulated by computer programs. The data files contain the elevation data of the terrain in a digital format which relates to a rectangular grid. DTMs are base for generation of bare earth contour lines.
Spatial Analysis
Based on results of topographical survey it was possible to perform various geospatial analysis of the area, including Slope Analysis to eliminate areas with steep slopes, Aspect Analysis to eliminate north facing slopes, and Area Solar Radiation Analysis to identify areas with best solar potential.
Definition of suitable areas for solar PV plant development
The next step of spatial analysis was to identify other land development constrains. Land constraints for a solar PV site refer to the factors that limit or affect the use of land for the development of a solar photovoltaic (PV) system.
These constraints can include factors such as land availability, zoning restrictions, soil type, current land classification (see Figure below), public infrastructure and facilities, environmental regulations, and other physical or legal considerations that may impact the feasibility of a solar PV project.
Understanding these land constraints is important for identifying suitable sites for solar PV development and for planning and designing a project that is efficient, cost-effective, and compliant with applicable regulations.
Results of suitability analysis
The site has been separated into four sub-zones with solar resource potential as well as land classification weighting in as decision-making factors. The later may lead to phased development of the site due to necessity to change land use destination.
The preliminary estimated capacities presented in Figure and Table below still do not take into account constrains related to different layout of solar PV modules, safety perimeters, main and perimeter roads, cable trenches and placement of power stations (central inverters and transformer stations).
| No | Description | Area [Ha] | Parcel Numbers | Land Class | Estimated Capacity [MWDC] | Ground Cover Ratio [%] |
| 1 | Zone A | 36 | 1-1, 1-13, 2-38 | Class 5 Field | 40 | 52 |
| 2 | Zone B | 58 | 4-5, 4-14, 4-21, 19-10, 19-11, 19-13, 464-0 | Class 5 Field | 60 | 52 |
| 19-14 | Class 2 Forest | |||||
| 3 | Zone C | 36 | 2-1 | Class 2 Field | 40 | 52 |
| 2-4 | Class 2 Forest | |||||
| 2-5 | Class 3 Pasture | |||||
| 4 | Zone D | 20 | 3-38 | Class 2 Field | 20 | 54 |
| Total Area: | 150 | Total estimated capacity: | 160 | |||