Combining tariffs, investment subsidies and soft loans in a renewable electricity deployment policy

•Insight on the cost-effectiveness of combinations of deployment instruments for the same technology.•A financial model is developed.•Feed-in tariffs (FITs) are combined with investment subsidies and soft loans.•The policy costs of combinations are the same as for the FITs-only option.•Therefore, combining deployment measures is not a cost-containment strategy.

Policy combinations and interactions have received a considerable attention in the climate and energy policy realm. However, virtually no attention has been paid to the analysis of the combination of different deployment instruments for the same renewable energy technology. This neglect is all the more striking given the existence in current policy practice of combinations of deployment instruments either across technologies or for the same technology, both in the EU and elsewhere. What renewable electricity support policies to use and, therefore, how to combine them in order to promote the deployment of renewable energy technologies cost-effectively is a main concern of governments. The aim of this paper is to provide insight on the cost-effectiveness of combinations of deployment instruments for the same technology. A financial model is developed for this purpose, whereby feed-in tariffs (FITs) are combined with investment subsidies and soft loans. The results show that the policy costs of combinations are the same as for the FITs-only option. Therefore, combining deployment instruments is not a cost-containment strategy. However, combinations may lead to different inter-temporal distributions of the same amount of policy costs and, thus, differently affect the social acceptability and political feasibility of renewable energy support.