The energy watchdog has claimed that it has helped deliver £210m worth of savings for Northern Ireland consumers over four years, with another £45m of savings predicted.
The Utility Regulator's annual report into electricity, gas and water provision said that domestic gas consumers in the greater Belfast area were paying the lowest standard tariff in the UK or Ireland.
However, Iain Osborne, chief executive of the body, has warned of price rises to come.
"Although energy prices have fallen recently, the long-term trend is likely to be upwards," he said.
The report also said that the planned termination of two power generation contracts at the AES Kilroot power station this November may result in £45m of savings over the next three years.
At the launch of the report, Professor Peter Matthews, chairman of the Utility Regulator, said that since 2006 the benefits the organisation had brought to consumers are, on average, nine times more than its costs.
Professor Matthews also welcomed the beginning of competition in the household electricity market and added that, as the independent regulator of NI Water, the body is "focused on reducing costs and raising service quality".
He added: "The forthcoming price control relating to the electricity network in Northern Ireland is vital for Northern Ireland's infrastructure."
NIE will publish its annual report next week.
Shane Lynch, director of electricity with the Utility Regulator, said that the recent sale of NIE infrastructure to Irish energy company ESB would benefit the consumer in the long run.