Power NI has announced that it is increasing prices by 5.6% with effect from 1st October.
The company say the price rise is due to increases in the costs of producing electricity, such as the cost of fuel used in power stations.
This will be the first increase since 2013 and has been agreed with the Utility Regulator.
Power NI supplies over 60% of local homes and has said that the increase will add just over £2 a month to a typical household bill.
Stephen McCully, Managing Director of Power NI, said: "So much is dependant upon world fuel costs, which are outside our control and which have an effect on the price we pay for wholesale electricity.”
"We have not increased our prices since 2013, so it is particularly disappointing for us that we have to do so now. However, as we were able to cut our prices over the last four years, a typical Power NI bill will still be roughly £80 less than it was in 2013.”
He continued: "Unfortunately we cannot avoid this increase, but what we can do, is encourage our customers to take up one of our discount offers, which may help offset it."
The company says, Power NI prices will still be significantly below the main suppliers in GB, the Republic of Ireland and across Europe.
Following the announcement on Thursday, the Utility Regulator said the main reason was increases in wholesale energy costs.
Jenny Pyper, Utility Regulator Chief Executive commented: "Agreeing an increase to Power NI's domestic electricity tariff is not a decision that we take lightly. We carry out extensive scrutiny of Power NI's costs to ensure that any change to their tariff is justified. Domestic electricity prices in Northern Ireland have not increased in four years, but unfortunately, due to rises in wholesale energy costs, this increase is unavoidable."
"We continuously review all the components that make up Power NI's tariff. Should wholesale energy or other costs decrease, our system of regulation in Northern Ireland allows us to act as soon as possible to ensure that this reduction is reflected in consumer bills.
She added: "Northern Ireland consumers also have a choice of five domestic electricity suppliers and I would encourage them to shop around and explore the options available to them."