Electricity prices in Jersey to rise by 9.5% next year
Chris Ambler, from the firm, said the rise was necessary to meet the extra costs of generating electricity locally.
He said it was the first above inflation rise for four years and was "regrettable but unavoidable".
The rise means customers will have to pay an extra £1.50 per week on average, Mr Ambler said.
He said the last major price rise had been 24% at the start of 2009, which followed a two-year price freeze.
One of Jersey's two power supply cables from France, Normandie 1, failed in June, after which engineers said it was beyond repair.
Since then, Jersey Electricity has had to buy oil to generate electricity at La Collette Power Station.
Mr Ambler said: "Normandie 1 has served the island very well since 1984 and we have been planning its replacement for a long time.
"The £60m project to install a third cable along a different route to enhance security has been ongoing for eight years.
"It is extremely unfortunate that planning delays outside our control have meant the loss of Normandie 1 before Normandie 3 has been commissioned."
He said the firm expected the cable to be commissioned in 2015 but it was doing all it could to advance the project.
Mr Ambler added his firm was investigating a "fast-track replacement" for Normandie 1 along its current route.