Thesis: Assessment of photovoltaic solar energy potential in Kenya

Abstract

Accessibility to affordable and sustainable energy resources could have a major impact to the economies of developing countries and in the livelihoods of the citizens of those nations. Solar energy is one of the readily available renewable energy resources and especially to the countries which are located within the tropics. Kenya is one of the countries in the tropical region and receives an average of 6.5 sunshine hours in a single day throughout the year. The main reason for the slow adoption of solar energy resources in Kenya has been the general lack of information of the spatial variability of the characteristics of solar energy potential within the country. The second reason has been due to the high cost of solar energy technology and the lack of a comprehensive legal framework in support of investment in solar energy sector. 

The aim of this work was to assess the potential of solar energy in Kenya and particularly the potential of photovoltaic solar energy generation. The main factors that have an influence on the incident solar radiation that were considered in the study were atmospheric transmissivity and the nature of topography. The influence of atmospheric transmissivity was factored in by modelling monthly transmissivity factors from a combination of cloud cover, diffuse ratios and a correction for the influence of elevation on atmospheric transmissivity. The contribution of topography on the other hand was factored into the model by applying hemispherical viewshed analysis to determine the amount of incident global radiation on the surface based on the orientation of the terrain. This was implemented through the Solar Analyst Tool in ArcGIS 10. In order to integrate the different spatial datasets in the model, GIS methods and tools were used.

The result of the analysis showed that on average, approximately 95% of the land in Kenya has the potential of receiving approximately 5kWh/m²/day throughout the year. From the analysis of the monthly data, the maps of monthly solar energy potential in the period between April and September had relatively large areas of land characterised as high potential areas when compared to the other months. This task successfully attempted to assess and to document the spatial variability in the characteristics of solar energy potential in Kenya.

Key words: energy, solar energy, renewable energy, radiation, GIS

Note: The online map of monthly and annual solar energy potential in Kenya can be found here.

GIS Project: Comparative analysis of solar energy potential in Kenya and Pakistan

The power of GIS is in the ability to combine different layers in order to create new insight about a phenomenon of interest. In this exercise, four main GIS layers were combined to map the potential of solar energy generation in Kenya and Pakistan. The four main layers were global solar radiation, cloud cover, land cover and the euclidean distance (from major towns and transport infrastructure). The choice of Kenya and Pakistan in this study was based on the fact that the two countries are located in different climatic zones with Kenya in the equatorial zone and Pakistan in the temperate zone. Additionally, my partner for the project was from Pakistan while I am originally from Kenya.

The data for this project were mainly from publicly available sources especially in the internet. ArcGIS and ENVI softwares were the main softwares used in the project. The figure below shows the methodology adopted for the project.

Project work for solar energy potential mapping

In the methodology above, Solar analyst in ArcGIS was used to carry out solar analysis on elevation layers for both countries. Secondly, distance analyst was used to create euclidean distance layers with reference to the major towns and roads, a representative euclidean layer was then generated by computing the average of the two layers. Thirdly the land cover layers obtained from different sources for the two different countries were rasterized to allow them to be combined with the other layers. Finally, NOAA-AVHRR CLASS imagery for both countries were analyzed to come up with a representative cloud cover layers for both countries.

With all the four layers ready, a weighted overlay procedure was carried out to combine the layers. Finally, map algebra was used to subtract water bodies and gazetted (protected areas) from the potential sites. The maps below show the map of potential sites in Kenya and Pakistan respectively.

Solar energy potential map of Kenya

Solar energy potential map of Pakistan

As a final step, zonal statistics was used to determine the administrative units with the highest potential in both countries. From the study, it was observed that due to the location of Kenya along the equator and also in view of the favorable terrain in close proximity to the equator, a relatively large portion of Kenya was classified within the very high or high potential areas as opposed to Pakistan.

The presentation that was made as part of this study is embedded below

References

• Fu, P. & Rich, P.M., 2000. The solar analyst 1.0 manual. Helios Environmental Modeling Institute (HEMI), USA. 
• Fu, Q., 1996. RADIATION ( SOLAR ). , (1981), pp.1859–1863. 
• Hammer, A. et al., 2003. Solar energy assessment using remote sensing technologies. Remote Sensing of Environment, 86(3), pp.423–432. Available at: http://linkinghub.elsevier.com/retrieve/pii/S003442570300083X [Accessed November 1, 2012]. 

Cartographic representation of the potential of solar energy in Kenya

This presentation was made as part of the Cartography and Geovisualization course at the University of Salzburg. The task was carried out together with two other student colleagues; Mrs. Romana Basir and Mr. Simon Haufe