Why Whitehill?

The salt deposits under parts of the Holderness Coast are the most extensive in the UK and are ideally suited to the development of salt cavern gas storage. In 2006, the area's suitability was confirmed by a programme of seismic testing.

We considered a number of factors in selecting Whitehill including the area's remoteness and proximity to existing dwellings, the natural screening and ecology of the surroundings, access to electricity, gas, sea-water and transport routes, as well as the geology of the area.

The exact size, location and final number of caverns will be decided in the ongoing design process, but the aerial photograph below shows the land under which the caverns could be created. It also shows the main sections of the project to be built above ground.



Gas processing facility

The processing plant will incorporate the majority of the above-ground equipment for the facility including compressors to inject the gas into the caverns and equipment that will control and monitor the quality of the gas being returned to the National Transmission System.

Wellhead compound

This area will hold a temporary drilling rig and equipment to create the caverns. By using 'deviated drilling' the wellheads for the caverns can be located in one central compound reducing the amount of land required at the surface. The compound will be landscaped and most of the permanent equipment will be housed underground.

Pump compound

Pipes will be laid to bring water in and to take the resulting brine back out to sea, where it will be safely and quickly dispersed. This compound is needed to drill these pipelines under the sea-cliffs to the beach.

Offshore platform (not shown)

A small platform will house equipment to pump seawater ashore.

Cavern creation

The salt caverns will be created by a process called solution mining. Water is pumped down a pipe inside pre-drilled wells into the salt around 1800m below the ground. Here it dissolves the salt and is removed as brine. The cavern shape can be controlled by adjusting the position of the pipes.

The salt layer will undergo extensive testing during construction with sonar surveys and samples extracted for laboratory analysis to ensure its suitability. We will also carry out pressure tests of the completed wells and caverns to ensure the completed scheme is safe.

The whole project is expected to take around six years to complete once construction starts.

The section above shows, to scale, the size, depth and indicative location of the caverns within the salt layer. It shows the other layers of rock and roughly when they were created.