1. Key World Energy Statistics;Agency,2014
2. World Development Indicators, Data Retrieved from World Development Indicators;Bank,2014
3. Nasa surface meteorology and solar energy, https://eosweb.larc.nasa.gov/cgi-bin/sse/sse.cgi?skip@larc.nasa.gov#s02.
4. Solargis GHI free maps, Solargis, http://solargis.com/products/maps-and-gis-data/free/download/yemen (Retrieved 18/08/2017).
5. Life cycle cost, embodied energy and loss of power supply probability for the optimal design of hybrid power systems;Abbes;Math. Comput. Simulat.,2014