Feed-in tariff and tradable green certificate in oligopoly

Feed-in tariff (FIT) and tradable green certificate (TGC) schemes are studied in a formal model and numerical example using the UK data. We find that if the markets were perfectly competitive, then feed-in tariff and the certificate price would be the same. However, when the markets are imperfect, they are generally different. While both the tariff and certificate price fluctuate around the difference between the costs of green and black energy, the tariff deviates more from the cost difference than the certificate price. The supplies of both black and green energy under FIT are higher than TGC, obviously as a result of subsidies. A troubling outcome is that the total energy supply increases under FIT as the renewables quota increases, which can negate other measures to mitigate climate changes such as demand management. Finally, using the data from the UK market, we find that social welfare under TGC is consistently higher than FIT for a wide range of values of the parameters.