40 metres ‘kill zone’ around brine pipe

Dublin-based renewable energy company Gaelectric wants to build a £300m compressed air energy storage (CAES) facility - only the third of its kind anywhere in the world - at Carnduff on the outskirts of Larne.

Compressed air would be stored deep underground in caverns specifically created for this purpose within geological salt layers. Energy is stored during periods of low energy demand (off peak), for use during later periods of higher demand.

The removal of salt from the creation of the caverns would produce a by-product known as brine, which would then be pumped into the sea off Islandmagee through a pipeline.

This process will only take place during the construction phase, but there are fears that the brine will cause severe damage to local marine life.

This week, the Larne Times spoke to an environmental consultant about the potential impact the brine could have.

Dr Brendan O’Connor, of Aqua-Fact International Services – who has been – commissioned by Gaelectric – said the affected area would be about roughly the size of a standard football pitch.

Dr O’Connor, who is based in Galway, explained: “The brine coming out of the pipe line off Islandmagee will be at 26 per cent salinity, while sea water is 3.5 per cent.

“The brine will disperse quite quickly because of the water depth and velocity in that particular area.

“However, there is no doubt that the concentration of the water surrounding the discharge point will increase.

“Anything above four per cent salanity will have an impact on local sea life. The area of sea bed where salinities will be higher than about four per cent will be an ellipse shape that measures about 160m long by about 40m wide.”

Dr O’Connor said the centre of this ellipse, an area of about 40m sq, will be a “kill zone”, where the salinity could be 10 per cent or higher.

“Anything attached to the sea bed in this kill zone will not survive,” he added.

However, he said mobile species such as fish, crabs and shrimp will be able to safely escape the affected zone.

“Once the brine discharge is stopped, the area will start to be recolonised immediately,” he said.

“But it will take a number of years for the marine eco-system to recover to what it was before the process began.”