The potentials of a reverse auction in allocating subsidies for cost-effective roof-top photovoltaic system deployment

• Return-on-investment of PV varies by roof suitability, system size and subsidy level.
• A reverse auction for subsidies is a cost-effective mechanism for PV system deployment.
• Simulating a reverse auction for a case study region using a detailed solar cadaster and historical subsidy data.
• Results indicate electricity generation increases by up to 18% and reductions of public funding by up to 41%.

Photovoltaic (PV) has developed to one of the most promising technologies for renewable electricity generation. The Austrian government currently provides subsidies for roof-top PV systems through a constant, administratively determined feed-in tariff or an investment co-funding. In both subsidy schemes, applications are approved on a first-come, first-served basis. There are concerns about (i) the selection of suitable roofs for PV systems, and (ii) allocating subsidies among applicants to deploy roof-top PV systems cost-effectively. Thus we analyze the potentials of a simple discriminative first-price reverse auction application scheme. Applicants define individually the required level of subsidy and those with the lowest request for subsidies are selected. In an ex-post analysis, we evaluate the potentials of such a scheme in increasing power output and saving public spending for the federal state of Vorarlberg in Austria. Results indicate a potential increase of cumulated produced electricity between 15% and 18% in comparison to the current policy. In addition, a reverse auction-based system would lead to savings of public spending per kWh between 20% and 41%.