The facility, based at the old Westmount Quarry site, took ten years to plan and build, and has been described as one of the most complex projects ever undertaken by Jersey Electricity.
Chris Ambler, the company’s chief executive, described the facility, known as St Helier West, as one of the most important infrastructure assets in the Island and thanked the engineers for bringing it into service on schedule and in time for winter.
‘St Helier West is the final piece in the jigsaw of our robust 90KV network ring. It relieves pressure on supplies to 80 per cent of St Helier – around 13,000 customers previously served by the Esplanade and Queen’s Road primary substations,’ he said.
‘It further enhances supply security and also future-proofs the network to meet the increasing demand for low-carbon electricity.’
Mr Ambler added that further work would soon take place to help blend the new substation in with its new surroundings.
He said: ‘Further landscaping will take place. Shrubs and trees will be planted and a public viewing platform overlooking St Aubin’s Bay will be incorporated and completed next year. Our objective is to leave the site in better condition than we found it.’
A total of 27,000 tonnes of material – including 5,000 tonnes of rock – had to be excavated from the former quarry site before construction could begin.
St Peter firm Jayen completed the preliminary work before handing the area over to specialist French contractors, Engie INEO.
Since then, transformers from Italy, cabling from Belgium and control systems from the UK have all been installed.
The substation is now one of five in Jersey which transform the voltage coming into the Island from France from 90,000 to 11,000 volts. The electricity is then distributed to a network of 787 smaller substations which further lower the voltage to 400 volts and 230 volts for use in homes and businesses.
