Financial measures for promoting residential rooftop photovoltaics under a feed-in tariff framework in Thailand

A feed-in tariff (FiT) framework has been implemented in Thailand since 2007 to encourage and stimulate the development of renewable energy. As a result, the capacity of solar photovoltaics (PVs) has increased significantly and has reached 1902 MW. Nevertheless, the installation of PVs on rooftops in the residential sector accounts for only a minute percentage (0.003%) of the total capacity of installed PVs. In this paper, a feasibility analysis of grid-connected solar PV rooftops for households under the present feed-in tariff framework was performed. The results demonstrate that the current feed-in tariff is not sufficient to promote investment in PV rooftops in the residential sector under the current market situation. Moreover, in order to support the current framework, additional supportive measures including (1) an appropriate feed-in-tariff rate, (2) personal income tax exemptions, (3) carbon trading, and (4) low interest rate loans, were proposed, and their effects were evaluated. The low interest rate loan appears to be the best measure for promoting and stimulating investment in residential-scale PV rooftops without additional subsidy. The leverage effect of debt, with different debt portions, loan terms and interest rates, was investigated to suggest a suitable policy.