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WQ.266/2018
WRITTEN QUESTION TO THE MINISTER FOR TREASURY AND RESOURCES
BY THE CONNÉTABLE OF ST. MARTIN
ANSWER TO BE TABLED ON MONDAY 3rd DECEMBER 2018
Question
Will the Minister, as shareholder representative, request confirmation from Jersey Electricity of the likelihood of failure of any, or all, of the submarine power cables and the expected time of repair for any such failed link; and will she also request confirmation of whether any plans exist to mitigate electricity usage in the 48-hour period that Jersey Electricity requires to start their slower-start generators?
Answer
The following information has been provided to the Minister by Jersey Electricity:-
Jersey has extremely reliable electricity supplies largely because of Jersey Electricity's ("JE") network design, its 3 submarine cables to France (which are typically operated in a "parallel" configuration) and the Company's restoration preparedness. Last year supply reliability was over 10 times better than the UK and the Company's best performance for 10 years.
The likelihood of failure of any of our submarine cables is low, and therefore very low that all 3 would fail at once. None of the three submarine cables currently in service has suffered any "electrical faults" and our asset strategy is to replace these assets before they become unreliable. The health of the cables is carefully monitored on an ongoing basis to allow for planned replacement at the appropriate time. In the unlikely event of failure of a submarine cable, an offshore repair would take approximately 12 weeks depending on the time of year, weather, location and repair vessel availability.
Having 3 cables in service (across 2 separate routes, connecting into different sections of the French network) gives the Island flexibility and resilience and means that JE can mitigate costs in the event that one of the cables is out of service.
Given the strength of our submarine cable system and number of cables, JE do not believe that there is a requirement to rely on its slow start (steam/ boiler) generation to meet its security of supply standard and therefore the steam/ boiler system is being retired.
Plans and systems exist to further mitigate any shortfall in capacity which include availability of fast start backup generation (5 diesel sets and 3 gas turbines). These assets are split across the Company's Queen's Road site and La Collette, and can typically be started and connected into the system within 20-60 minutes.
JE has also recently updated its System Integrity Protection System which continually monitors the 90kV network and which responds rapidly to mitigate any failure on the network.
Further details on JE's security of supply standard are set out on the Company's website, www.jec.co.uk, and in its Annual Accounts, https://www.jec.co.uk/about-us/investor-relations/financial-figures-and- reports/.