Analysis of temporary variability of the total intensity of solar radiation when assessing energy resources

The results of the analysis of temporary variability of average monthly and annual amounts of solar radiation in Ukraine for the period 2011-2020 are presented. Measurement data were compared with earlier periods and the standard period of 1961-1990. The statistical characteristics of the series of changes in solar radiation have been determined. Comparison of the characteristics of solar radiation with the normative data of SSU NBV .1.1-27-2010 was made. It has been shown that in recent years the annual amounts of direct radiation have increased by 18-23%. The total annual radiation in 2020 increased by 6% according to the period 1961-1990. The analysis of the calculated results of determining hourly values and daily sums of direct and scattered radiation obtained using empirical dependencies of engineering methods is carried out. The efficiency of using the sustainable potential of solar energy depends on the climatic characteristics of this area or region. Inconsistencies in regulations can therefore create a problem where the best places for energy production lack public interest, infrastructure and cost-effective consumption. Depending on the regional climatic conditions of Ukraine, the solar energy potential varies from 1400 MJ/m2 in the western regions to 1950 MJ/m2 in the eastern regions. An important characteristic of solar energy resources is the duration of sunshine. For the conditions of Kyiv, the average monthly value of the actual duration varies from 180 hours in March to 120 hours in November. The possible annual duration of sunshine varies accordingly from 4452 hours (2011) to 4481 hours (2020). The maximum values are observed in June (331 hours) and August (334 hours). In the southern regions of Ukraine, the actual annual duration of sunshine for Odesa conditions varies from 2387 hours (2011) to 2709 hours (2020). The criterion for the expediency of using solar energy is the annual number of clear days of more than 200. The number of clear days is not given in SSU.