Red Eléctrica de España has invested a total of €325.8 million since 2011 in the renovation, improvement and maintenance of the Canary Islands’ high-voltage transmission grid. Furthermore, between 2014 and 2018, investment in new electricity grids in the Canary Islands totalled €326.3 million and a further €487.9 million investment is planned up to 2021. These figures illustrate the effort made by Red Eléctrica to comply with its mission, which is to guarantee the quality and security of the supply in Spain and to bring the Canary Islands’ transmission grid up to the standards of the grid on the Spanish Peninsula.

Of the €325.8 million, €181.8 million were allocated to carrying out maintenance tasks on the infrastructure that makes up the high-voltage transmission grid of the archipelago. The remaining amount, €144 million, corresponds to investments that the Company has made during this period to strengthen and renew the assets of the transmission grid to make it more robust and meshed. These investments correspond mainly to the MAR Project (Grid Asset Improvement), which in this period has enabled, among other improvements, to reduce the average interruption time of the system.

In this same period, Red Eléctrica has also invested 2.2 million euros in the Granadilla substation, the facility in Tenerife where the electrical incident occurred last Sunday. At present, Red Eléctrica de España is continuing to investigate the causes that led to the electrical failure.

Regarding the Granadilla substation, this investment is broken down, on the one hand, into €1.2 million focused on the maintenance of said facility and €1 million dedicated to the renovation and strengthening of the substation assets. The maintenance tasks carried out by the Company can be categorised into several types, noteworthy among which are the scheduled and preventive maintenance.

At present, the Canary Islands as a whole has 1,384 km of line circuit and 59 substations in service. Specifically, Tenerife's high-voltage transmission grid consists of a total of 618.75 kilometres of line and 23 substations. The electrical incident in Tenerife, which began last Sunday at 1:11 p.m. and caused what is known as a ‘Zero Energy’ situation, was due to a technical failure at the Granadilla substation in the south of the island.

Actions carried out in the Granadilla substation

The Granadilla substation, a facility with two voltage levels, 220 kV and 66kV, was acquired by Red Eléctrica de España in 2010 in compliance with the regulation that establishes the voltage levels that are considered as electricity transmission grid voltages for both the Balearic Islands and the Canary Islands. Since then, the Company has managed the substation’s assets and has put in place and followed maintenance strategies based on the Company’s maintenance policies, expertise and know-how and which are specially designed for the equipment of said transmission grid. Furthermore, Red Eléctrica defined the strategies taking into consideration not only the recommendations of manufacturers but also the good practices of other organisations of the sector.

In total, since 2011 almost 3,000 maintenance actions have been conducted throughout the substation, which are divided into five major technological areas; high voltage equipment, auxiliary services, protection systems, control systems and telecommunications systems.

Similarly, several categories of actions carried out to date should also be highlighted:

• Scheduled maintenance actions: defined by Red Eléctrica in order to perform scheduled and diagnostic maintenance of the facilities, mainly carried out on a periodic basis, in order to ensure the correct state of operation of the facilities and detect incipient failures. To date, this category represents 84% ​​of the activity carried out.
• Other maintenance-related actions: detailed maintenance and improvement actions in its facilities aimed at avoiding, among other things, possible failures and/or incipient defects. This category represents 16% of the activity carried out.

In this way, once all the activities included in the maintenance history are analysed in detail, the correct application of the maintenance strategies defined for the substation is made evident.