Q & A: energy needed to understand bills What has caused the confusion? David Cameron on Wednesday pledged that the government would force energy suppliers to offer every customer their lowest tariff. News of what would be a significant policy change caught the industry, as well as ministers at the energy department and the regulator, by surprise. On Thursday, John Hayes, the energy minister said the new rules would help consumers get "the best deal" on their electricity and gas bills - but stopped short of confirming it would be the lowest price. Cue, more confusion. In a separate speech on the upcoming energy bill, Ed Davey, secretary of state for energy, did not make any mention of Mr Cameron's pledge. Why does it matter? Inflation fell to its lowest level in almost three years this week but energy bills just keep going up. Four of the big six energy suppliers have announced winter price increases above inflation over the past few weeks. Public trust in energy companies is low after price rises and what critics see as deliberately confusing marketing. The companies have insisted that a large proportion of bills is outside their control - in the form of the wholesale natural gas price. The government wants to see more competition among suppliers and also asked the industry last year to simplify its bewildering array of tariffs. The big problem is that although most people buy their gas and electricity from the big six suppliers, when they do shop around, they are faced with more than 400 tariffs. A lot depends on how consumers pay, for example by direct debit, or online. YouGov research on behalf of uSwitch, a consumer website, found 75 per cent of people find energy bills confusing. Only four in 10 could understand the calculations. Who is at fault? Critics accuse the industry of deliberately fostering confusion. The companies hit back that they have already simplified many of their tariffs. The uSwitch website said Mr Cameron's proposal could backfire as it would cause companies to withdraw their cheapest tariffs. The devil will be in the detail - and there is little clarity at the moment. But be prepared for more change. On Friday Ofgem, the energy regulator, will publish its own proposals on the way that gas and electricity companies sell to customers. It wants all suppliers to offer a standard tariff for each payment method and per fuel to make it easier to compare between companies. Suppliers can still offer as many innovative tariffs as they like but these will have to be at fixed prices and, on the whole, for fixed terms. Bills will also become simpler. Ofgem wants them to display charges in the form of pounds or pence per month, as well as per kilowatt hour. It wants these changes to be in place by next summer. If maths PhDs, accountants and engineers struggle to understand energy bills, what hope is there for everyone else?, writes Elaine Moore In a test overseen by the head of mathematics at Edexcel, an exam board, more than 30 professionals were asked by consumer group Which? to work out what their bills would be if they used a particular standard tariff. All but one failed. The energy industry has found it difficult to produce consumer friendly bills, in spite of regular prods by the regulator. In 2010, suppliers were told to include more detail, including the annual cost of gas and electricity and any premiums or discounts received by a customer. In 2011 they were told they were baffling consumers with information overload and were ordered to simplify tariff structures and make bills easier to understand. The confusion is partly the result of the rise in price options over the past few years, meaning a single household can be offered hundreds of options depending on factors such as when they use the most energy and how they pay. British Gas said in June it was launching "billing for dummies" as part of its campaign to improve transparency. But so far the industry's best efforts appear to have been in vain. Five days ago Which? released the results of another energy tariff test in which members of the public were presented with a range of standard energy tariffs and asked to identify the cheapest. Nine out of 10 failed.