An output simulation is one of the first steps in planning a photovoltaic power plant (PVP) at a certain location. Various computer codes already exist to assess the energy output of a PVP, when fed with the relevant meteorological data. For the alpine area, however, there is no appropriate data considering the altitude of the site available. A computer code las been written to check the available raw data for plausibility and to fill in missing data synthetically. On the basis of 6 yr of measured data a test reference year (TRY) has been developed for the town of Leonding and the summit Loser. They are located just 80 km apart but have a 1250 m difference in their altitudes. For comparison, these new TRYs, together with other already existing TRYs from different places in a surrounding area of about 300 km, are used for calculation of the expected energy output of a PVP. A clear increase of energy yield with higher altitude can be observed. The summit Loser (1550 m), with the highest altitude investigated in this study, proved to be the most productive location. Besides the clearer sky and snow reflection, the lower temperature as well as better cooling of the panels by the wind in the Alps contribute to the higher amount of energy output.