COST-BENEFIT ANALYSIS OF CONVERTING AGRICULTURAL LAND INTO SOLAR FARM USING RS & GIS: CASE OF TARLAC PROVINCE
- Department of Geodetic Engineering, University of the Philippines Diliman, Quezon City, Philippines
Keywords: Solar farms, Remote Sensing, Geographic Information Systems, Suitability Map, Rice Yield Estimation
Abstract. The Philippines relies heavily on fossil fuels. With its high energy consumption, the country is at risk economically because of possible supply constraints by exporters, and price fluctuations of fossil fuels. One alternative to fossil fuels is solar. This study aims to explore the use of satellite data analytics and Geographic Information System (GIS) in making a granular site suitability assessment for solar photovoltaic (PV) projects in the province of Tarlac and perform a cost-benefit analysis for rice field conversion to solar farms. Remote sensing (RS) and GIS techniques were used to estimate values of factors and constraints to generate a suitability map of solar farm installation in Tarlac considering rice yield. Input data such as Sentinel 2A image tiles and statistical data from databases online were gathered and geospatial analyst processes were done, particularly in assigning weights to the said factors and constraints. For accuracy assessment of image classification, values of kappa coefficient (k) and overall accuracy (OA) were computed. A final suitability map is then applied together with the constraints. This is then compared with existing and upcoming solar farm projects to see if the suitability map can be considered or there is analysis on whether a prime rice field had been converted. Costs, on one hand, such as the forgone net profit from the agricultural land and rice yield loss was presented. The benefits, on the other hand, include the estimated net returns of the solar farm, the amount of energy generated, and the reduced carbon emissions. Different ranges for several of the variables were considered so a more thorough analysis could be presented. Values of k and OA were 62.2% and 71.27%, respectively, indicating a satisfactory accuracy of image classification. In all instances it was shown that in terms of the costs and benefits considered, agricultural land conversion into solar farms may be beneficial for the province of Tarlac. The study showed that this would match the estimated net profit of rice farm areas selected at around ₱123 M with ₱133 M, but at best estimated net profits could go as high as around ₱5 M. This study has also emphasized the environmental benefit of converting agricultural areas to solar farms by lowering the province’s dependence on non-renewable sources of energy, particularly coal in this case. The approximated reduction in emissions was 33.7% of the emissions of the whole province. It was also notable how much of the national rice supply could be affected as rice supply for more than 200,000 people for a year would have to be forgone.