## 4 The GCC's Solar and Wind Energy Resource Potential
### Solar Energy  
The importance of implementing large-scale photovoltaic (PV), concentrating solar power (CSP) and other solar energy applications and their economic benefits across several territories around the world has been analyzed in many previous studies [33, 34, 35, 36, 37, 38, 39, 40, 41, 42]. The success of worldwide governments in developing solar energy technology primarily relies on the in-depth awareness of solar intensity levels and the distribution of global solar radiation, which is a challenging task due to the fact that, to date, the information on a global scale is limited. [PERSON] et al. [43] and [PERSON] et al. [44] mention that, based on the geographic location of the GCC region and the annual insolation (aggregated hours of sun, adjusted for solar intensity), the region is among those with the highest solar potential in the world due to the large annual availability of solar radiation. The annual average global solar radiation in the GCC region is estimated at 6 kWh/m\({}^{2}\) per day, and the direct normal irradiance (DNI) is around 4.5 kW/m\({}^{2}\) per day [44]. The abundance of solar energy resources depends on the sun's irradiance parameters and spectral distribution. [PERSON] et al. [45] mention that if the countries of the Arabian Peninsula collaborate strongly to this end, not only would Saudi Arabia be able to become a main solar energy hotspot in Asia, but the whole GCC region would be able to achieve this. Among the alternative renewable energy sources in the GCC region, solar energy stands out. [PERSON] et al. [46] mention that the GCC countries have a remarkable opportunity for the use of alternative energy sources, in particular solar energy, and, therefore, should take a more proactive role in terms of investment in emerging technologies. According to [PERSON] et al. [47] and [PERSON] and [PERSON] [48], the highest annual solar radiation range, 2200 to 2500 kWh/m\({}^{2}\), was recorded in Oman. In addition, the UAE has the second highest annual solar radiation of 2285 kWh/m\({}^{2}\), which is supported by average sunshine of 10 h per day [49, 50] due to its location. Saudi Arabia and Kuwait have relatively equal annual solar radiation of 2200 kWh/m\({}^{2}\)[51, 52, 31]. Kuwait is characterized by high average daily sunshine, around 12 h per day. A mean of nearly 2180 kWh/m\({}^{2}\) for annual solar radiation was recorded in Bahrain [53]. Furthermore, the lowest value of annual average solar radiation was observed in Qatar at 2113 kWh/m\({}^{2}\)/year, with average daily sunshine of 9.5 h [54]. Nowadays, the GCC countries give special and increasing attention to the adoption of solar energy in order to reduce the energy cost of the growth demand. [PERSON] et al. [55] stated that the total annual mean of global horizontal irradiance (GHI) over the Arabian Peninsula, including the GCC region, is between 6 and 8.5 kW/m\({}^{2}\), and the DNI is between 3 and 6.5 kW/m\({}^{2}\). The values of diffuse direct horizontal irradiance (DHI) are high among the majority locations of the region and curtailed along the Red Sea and surrounding coastal shorelines, at 1.2 and 4 kW/m\({}^{2}\), respectively [55]. This study provided comprehensive evaluation of the solar energy resources with high-resolution spatial date over the GCC region on the basis of analysis of historical data spanning 37 years for the period 1980-2017, gathered from 46 in situ radiometer stations over the region and supported by assimilative weather research. Figure 2 summarizes the performance of GHI, DNI, and DHI in W/m\({}^{2}\), including the diffuse fraction (DHI/GHI) of the GCC region. The diffuse fraction (DHI to GHI ratio) indicates enhanced cloud cover and/or a higher aerosol load over the average duration [56] and is high over the northern locations and low over the southern parts of the central GCC region during the winter, while it is high across the southern and central regions, and low over the north during the summer [55].