East to west - The optimal tilt angle and orientation of photovoltaic panels from an electricity system perspective

Both, the historic analyses and the model results for Austria and Germany suggest that at present PV penetration levels, the angle combination that maximizes the output of a PV system also provides the highest spot market value and consequently minimal total system costs. For higher shares of PV in the system the model suggests deviations from those angle combinations to be optimal. For additional PV capacity of up to 40 GW (72 GW in total) a slight shift to easterly orientated PV modules is observed. For very high penetration levels of more than additional 100 GW optimal deviation angles deviate strongly from the output maximizing angles and the model shows optimal angles to be up to 20° steeper and orientations from east to west. However, the impact on total electricity generation costs is very low even for extremely high shares of PV in the system (<1% change in total costs). It is also found that despite of optimized installation angles, the average market value of electricity production from PV drops significantly from 41 €/MW h at the base year 2012 to below 24 €/MW h for additional 40 GW which has strong implications for the competitiveness of PV in the future. Marginal CO2 emission reductions however decline slower than the market values as PV cuts into production from coal power plants.