Inertisation of the Castor underground storage facility now complete

23 November 2015

Enagás is finalising the hibernation phase of the Castor underground storage facility, pursuant to the government's stipulations in Royal Legislative Decree 13/2014 of 3 October adopting urgent measures relating to the gas system and the ownership of nuclear power plants.

The status of the phases making up the hibernation process is as follows:

Phase 1. Inertisation
This phase has been completed, and there is now no gas on the surface, on the platform, in the gasline or in on-land facilities. The infrastructure's gas pressure was reduced to a bare minimum, and any gas remaining was drawn out to a controlled schedule. Surface gaslines were also filled with nitrogen (an inert gas used in gas infrastructures to render them completely safe) as part of the insulation process.

Phase 2. Preservation of equipment
Work to preserve and maintain equipment completely safe and operational has now been carried out as planned. Specifically, all plant and platform compressors were preserved: all electrical components were protected, and valves were greased down and coated with insulation material to protect them against the maritime environment.

Phase 3. Sealing the wells
A check was made to ensure that each of the 12 storage wells are properly sealed, and that the valves on the surface and at a depth of 150 m can guarantee the sealing. This work was carried out to meet stipulations of the Royal Legislative Decree stating that gas may not be injected or extracted, and that the structure of the storage facility may not be altered.

To complete the sealing of the well, mechanical steel plugs are being fitted in addition to the two valves already in place: one for the valve at a depth of 150 m under the sea bed, and another nearer the well head located on the platform. This provides a quadruple seal for the wells.

Following work carried out to date, Enagás has met the objective of Royal Legislative Decree 13/2014 to make the facility safe, with no gas on the platform, in the gasline or in on-land facilities; not altering the structure of the storage facility and carrying out tasks for proper maintenance and preservation of equipment.

From the outset, at all times Enagás' priority concern has been and remains the safety of people, property and the environment. The company will provide further information as work progresses.


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