This thesis examines the prospective need for subsidies for photovoltaics in Austria in times of decreasing investment costs. As an example, rooftop-mounted photovoltaic systems with 5 kW, 30 kW, and 100 kW peak power output are investigated. They feed to the grid as well as directly supply power to a household or a commercial building, respectively. The demand for subsidies is calculated using the net present value of the project. The results show that 5 kW PV installations will be profitable without subsidies when constructed in 2020 or later. 30kW and 100kW PV units are profitable today even without subsidies. Regarding a continuous promotion policy, a sudden halt of subsidies should be avoided. Instead, a declining subsidy is calculated that takes decreasing investment costs into account. Using this promotion scheme, new PV installations would only receive subsidies until 2023. This complies with the 'Guidelines on state aid for environmental protection and energy 2014-2020'. In these guidelines, the European Commission defined their goal for established renewable energy sources to become grid-competitive in the period between 2020 and 2030. According to these guidelines, subsidies should be phased out and should contribute to integrating renewable electricity in the market. After an evaluation of different promotion schemes an investment based promotion scheme seems to be best suited for PV installations. Owners of PV installations would be incentivized to maximize their own consumption and sell excess electricity on the market.