Assessment of the Technical Potential of PV Stations on the Example of the Fergana Valley. Part II: Analysis of Sunny, Partly Cloudy and Cloudy Days

The second part of the research presents an analysis of daily average data on cloudiness (cloud cover) in the Fergana Valley based on an 8-point scale for the period of 2000–2022. The main focus is on the number of clear, partly cloudy and cloudy days, as well as the number of days without sun. It was revealed that the largest number of clear days per year was recorded at the Boz weather station (168 days), while the smallest was in Fergana (112 days). As for partly cloudy days, the maximum number was recorded at Yubileinaya weather station (81 days). The maximum number of cloudy days was observed at the Fergana weather station (186 days). Based on the results and the annual dynamics of clear days, the locations in the region of Boz and Kokand weather stations appear to be the most suitable for installing solar power plants due to their potential for the efficient use of sunlight. Also, despite of the summer potential, in winter the number of clear days decreases, which can affect the performance of solar power plants. This is especially true for the Fergana weather station, where the number of cloudy days in December and January can reach 23. On average, the Andijan, Boz, Yubileinaya, Pap, Kokand and Kuva weather stations, observe 3–4 consecutive days without sun per year. At the Fergana weather station, this value is 4–6 days. The obtained results may be useful for the further sun energetic development in this region.