Uncertainty in power system analysis is increasing, mainly due to decentralized generation and the related spatial distribution of power plants, as well as the inherent volatility of renewable energy sources. In Austria, this development is reflected in a high number of photovoltaic grid connection applications in recent years. On the consumption side, there are changes in grid loads due to the increasing electrification of society, which is reflected, for example, in a rising number of electric vehicles. These aspects of uncertainty in generation and consumption must be considered in the planning process of distribution grids. A proper way to include uncertainty in the hosting capacity analysis of power grids are probabilistic load flow calculation methods. This paper provides an introductory overview of probabilistic load flow analysis, available calculation methods, required input parameters and the interpretation of results. This paper focuses on photovoltaics, so a correlation analysis of historical power generation measurements of spatially distributed photovoltaic power plants in Austria is presented. Furthermore, an insight into the development of Austrian photovoltaic grid connection applications from recent years is given.