GIS-based weighted overlay model for wind and solar farm locating in Sri Lanka

With regard to wind and solar energy, research has shown a clear discrepancy between the amount of energy currently being used with the existing potential. The present research has attempted to develop a geographic information systems (GIS) based weighted overlay model to identify potential locations for the development of wind and solar farms in Sri Lanka, which are rapidly advancing renewable energy resources globally. Four major land-use types were considered for the model development as least productive land areas to establish wind and solar farms, namely, barren lands, sand areas, open forests, and scrublands. Nine and seven criteria were identified for the wind and solar farm siting respectively, and the relative weights for each criterion were obtained through focused group discussions. The weighted overlay model was used to locate suitable areas and higher the values generally indicate that a location is more suitable. The outcome of the weighted overlay model shows that for the wind farm locating, 141 km² of highly suitable lands available accounts for 3% of the total land area of Sri Lanka. Furthermore, the model results indicated a total area of 99 km² as highly suitable for solar power generation. Central, Sabaragamuwa, Uva, and Northern provinces were found to be the most suitable for wind farm locating and Eastern, Southern, and Northern provinces we identified as highly suitable for the solar farm locating. The model validation performed by overlaying the results with the existing solar and wind farm map of Sri Lanka indicated that the highly suitable, moderately suitable, and marginally suitable lands identified by the weighted overlay lied within 1 km radius of the existing wind and solar power plants. Thus, it can be concluded that GIS-based weighted overlay model can serve as a primary screening tool to shortlist the optimum land areas to locate future solar and wind farms in any selected geographical location.