Consumers are "confused" and "bewildered" by the vast array of energy tariffs available to them, new research by Which? has revealed.
Ahead of Energy Secretary Ed Davey's party conference speech, the consumer watchdog has highlighted a wide variation in the standing charges in consumers' energy costs.
A standing charge is a fixed amount applied to a daily or annual gas and electricity bill.
The investigation focused on the available range of gas, electricity and dual fuel deals and standing charges available to a specific customer in one region of the country.
It showed there were more than 109 tariffs that included 75 different standing charges.These standing charges varied from zero up to £402 a year on individual gas and electricity deals combined and by as much as £373 on a dual fuel tariff.
Which? is now calling for simple tariffs, without standing charges and displayed in the style of petrol forecourt prices, to make it easier to spot the cheapest deal.
The Government's energy regulator Ofgem is currently reforming the energy market in order to simplify the bills, although Which? has criticised its plans, claiming companies will still be allowed to include a standing charge as well as a unit price in their tariffs.
The company described the array of charges as "bewildering" and the market "too confusing for consumers to find the best deal for them".
Which? executive director Richard Lloyd said: "At a time when consumers are struggling with the cost of living, and rising energy bills are one of peoples' biggest financial worries, the Energy Secretary must step in to make it easier for consumers to work out the cheapest deal.
"Ofgem's current plans to reform energy tariffs do not go far enough to simplify the market for consumers. If the Government fails to take more radical action, people will not feel confident that they are paying a fair price for their energy."