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GIS · AHP · Multi-Criteria Decision Analysis

GIS-Based Optimum Site Selection for Solar Electric Vehicle Charging Station: BP Highway

📅 July 6, 2025 🏛️ Kathmandu University 📍 BP Highway, Nepal 👥 5 Members

01 Abstract

Solar-based renewable energy adoption is in its early stage in Nepal's power system. This study employs the Analytic Hierarchy Process (AHP), a robust MCDM technique, to assess site suitability for solar-powered EV charging stations along BP Highway in Gandaki Province. Criteria including solar radiation, slope, aspect, LULC and elevation were used for solar panel suitability, while distance from highway, distance from existing charging stations, slope, soil bulk density and LULC were used for EV station selection. A weighted overlay analysis generated the final suitability map with CR = 0.058, and the final combined index was computed as 0.5×Solar Panel + 0.5×EV Charging Station.

02 Background & Problem

Nepal receives an average of 300 days of sunshine annually, with solar irradiance of 4.5–5.5 kWh/m²/day. The BP Highway - connecting Dhulikhel to Bardibas over 158km - is Nepal's most economically active corridor. Yet EV adoption faces a structural problem: there is no systematic, data-driven framework to locate charging stations.

Traditional internal combustion vehicles have dense petrol pump networks. EV users face range anxiety because the charging infrastructure is underdeveloped and not spatially optimized. This study addresses that gap using GIS and MCDM to identify where solar-powered EV charging is both viable and accessible.

03 Study Area

The BP Highway spans 158km through Bagmati and Madhesh Province, centered around the Kavre, Sinduli, Ramechhap, and Motahari districts. A 2km buffer around the highway was used as the analysis extent. The route exhibits diverse topography - from Mahabharat hill regions to fertile valleys - with solar irradiance levels between 4.5–5.5 kWh/m²/day throughout.

28°14′N · 85°32′E (avg) 158 km corridor 2km buffer zone WGS 1984 UTM Zone 45N

04 Criteria & Reclassification

Each criterion was independently reclassified into four suitability categories: Highly Suitable, Moderately Suitable, Low Suitable, Not Suitable. Two separate suitability analyses were run - one for Solar Panel placement and one for EV Charging Station siting.

☀️ Solar Power Plant Criteria
  • Solar Radiation (Wh/yr/m²) - ArcGIS Solar Tool
  • Slope (degrees) - derived from DEM (12.5m)
  • Aspect - south-facing highly suitable
  • Elevation (m) - 1504–1961m most suitable
  • LULC - bare ground & rangeland preferred
⚡ EV Charging Station Criteria
  • Distance from Highway - 0–500m best
  • Distance from Existing Stations - >5km best
  • Slope - 0–5° highly suitable
  • Soil Bulk Density (kg/m³) - 141–150 best
  • LULC - bare ground & rangeland

05 AHP Weight Distribution

Pairwise comparison matrices were constructed and validated with a Consistency Ratio (CR) of 0.058 for EV station and 0.08 for Solar panel (both below the 0.1 threshold).

EV Charging Station Weights
Distance from Highway43%
Existing Charging Station Proximity23%
Slope17%
LULC11%
Soil Bulk Density6%
Solar Panel Weights
Solar Irradiance53%
Slope18%
Aspect13%
LULC11%
Elevation5%

06 Data Sources

DEM

ASF Data Search · 12.5m × 12.5m resolution

Solar Irradiance

ArcGIS Solar Radiation Tool · Wh/yr/m²

LULC

Sentinel · ArcGIS Living Atlas · 10m×10m

Soil Bulk Density

ISRIC World Soil Information · kg/m³

Road Network

Overpass Turbo (OpenStreetMap) · 158km total

Existing EV Stations

Manual collection via web research → CSV → GIS

07 Results & Conclusion

The final combined suitability index (0.5×Solar Panel + 0.5×EV Station) produced a comprehensive map of optimal sites. Field validation confirmed that highly suitable areas feature large open spaces with strong solar access, while unsuitable zones were predominantly dense built-up regions.

CR = 0.058 (EV) CR = 0.08 (Solar) 4 Suitability Classes Weighted Overlay Final Map Field Validation Conducted

The study demonstrates that GIS + AHP can provide a reproducible, evidence-based framework for sustainable energy infrastructure siting - a methodology directly applicable to other highways across Nepal.