The generation of electricity on "solar farms" was specified in installations of up to 100 kW of nominal power, applying the regulations that set this power limit in order to receive the maximum retribution for the energy generated. Once this power was reached, the tariff was reduced. For this reason, "solar farms" became popular on low-value rural land accessible to small investors and added to municipal treasuries through activity licences.

Since Spanish Royal Decree 1578/08 went into effect, the engineering designs of "solar farms" have been set up as Photovoltaic Groups of up to 10 MW of nominal power, with a single premium per kW/h generated, eliminating the original figure of the "solar farm". The technical configuration maintains its original design (parallel groups of strings with 8-10 modules in sequence which lead to several inverters for transforming the continuous current generated into alternating current), with slight variations depending on the peak power to be installed.

Royal Decree 1578/08 replaced Royal Decree 661/07, which launched the photovoltaic sector in Spain through the establishing of equivalent premiums, with the consequent effects on R+D, technological development, operational cost reduction and job creation. This new decree established quarterly quotas and reduced the tariffs for the energy generated. It had the effect of paralysing investments, doing away with employment and pushing companies to compete in foreign markets.