The problems of optimising the placement of photovoltaic panels to ensure the most stable power generation are considered. Method for assessing the risks of solar power plants operation instability in the based on taking into account the climatic characteristics of the variability of the insolation and snow cover using GIS technologies is presented. This approach is especially important for Russia, a country with a wide variety of natural and climatic conditions. To test this technique, we calculated the intra-annual and year-to year variation of the statistical characteristics of the total insolation incident for regions of Russia. The use of GIS technologies made it possible to assess the distribution of the features of the variability of solar radiation over the area. This paper presents the results of calculations and constructed maps for the Republic of Altai, the region of Russia with heterogeneous insolation conditions, where solar energy has been actively developing recent years. In these territories, zones with the lowest indicators of variability in the input of solar radiation have been identified where a high level of stability of electricity generation on photovoltaic power plants can be predicted.