In 2010, Red Eléctrica acquired, in compliance with Law 17/2007, of 4 July, the Balearic Islands’ and Canary Islands’ assets and other assets on the Spanish peninsula pending transfer from the electric utility companies. This purchase completed the asset acquisition process that began in November 2002 and which allowed Red Eléctrica to increase its asset base. This acquisition was of the utmost strategic importance because it represented the definitive consolidation of the model which establishes a sole transmission agent and electricity system operator (TSO).
On 29th July 2010, Red Eléctrica and Hidrocantábrico Distribución Eléctrica reached an agreement by which Hidrocantábrico Distribución Eléctrica sold its electricity transmission grid assets to Red Eléctrica de España S.A.U.
On 23th July 2010, Red Eléctrica and Unión Fenosa Distribución signed an agreement by which Unión Fenosa sold its owned transmission assets to Red Eléctrica; excluded from this operation were those facilities of 220 kV which, due to their particular characteristics and functions, remained under the ownership of the distributor.
On 1st July 2010, Red Eléctrica and Endesa signed an agreement through which Endesa Distribución sold all of its owned transmission assets to Red Eléctrica, in agreement with Law 17/2007, of 4 July 2007. The transaction affected both the insular and peninsular electricity transmission grids; on the Canary Islands and the Balearic Islands the lines with voltages of 66 kV, 132 kV and 220 kV; and on the Spanish peninsula this was limited to the assets of 220 kV.
In November 2004, Red Eléctrica reached an agreement for the acquisition of the transmission assets of Enel Viesgo and on 15 February 2005 Red Eléctrica reached an agreement, formalised on 30 June 2005, with the CVC investment fund in order to acquire its 75% shareholding in Redalta, the company that controlled the transmission assets that belonged to Iberdrola. This acquisition process meant that Red Eléctrica owned 99% of the transmission grid on the Spanish peninsula, with the transmission assets of Hidrocantábrico yet to be purchased.
In November 2002, Red Eléctrica concluded agreements with Endesa and Unión Fenosa for the acquisition of their respective transmission grids. In addition, Red Eléctrica acquired 25% of the share capital of Redalta, the company through which the legal process involved in purchasing Iberdrola's transmission assets was handled. The assets acquired from Endesa and Unión Fenosa amounted to 205 km of 400 kV lines and 6,851 km of 220 kV lines, in addition to 927 substation bays and approximately 4,500 MVA of transformer capacity.