Nevertheless, variable renewable producers benefit from a tolerance for deviation of 20%, while conventional producers are accorded only 5%. However, in this case renewable producers receive a regulated premium over and above the hourly electricity price, the premium payment representing the presumed positive externality stemming from the use of the renewable technology. In some cases, the remuneration for renewable producers has also seen floors and caps put in place to mitigate the uncertainty resulting from variable electricity prices (such as in Spain, Royal Decree 661/2007, NREL, 2010).