Wholesale costs are the biggest contributor to Power NI's domestic bills. They account for just over forty per cent of what you pay. These costs include the price of the fuel burnt to generate electricity. But they also cover the cost of keeping power stations on standby. As a regulated supplier, Power NI is entitled to recover all its costs. If prices, which have to be set up to a year in advance, are insufficient to meet its bills, the company can and does add what it is owed to next year's tariff. The contrary is also true Network costs, which cover the cost of moving electricity from power plants to homes makes up 28 per cent of the end cost. A further 12 per cent is down to billing and meter reading with various levies and fees making up the rest.