The Spanish legislation for the regulation of renewable energy (Royal Decree 661/2007) foresees two options for the plant operators to sell their electricity: either based on a flat-rate price or a premium tariff. The latter means that the operators will participate directly on the electricity market. This study from 2008 assesses the theoretical potentials of the premium tariff compared to the flat feed-in tariff.
The paper concludes that the premium tariff has the potential to exceed the flat-rate price. The storage capacity has however an important impact on the revenues.