Energy watchdog Ofgem said it shared EDF Energy's goal of a simpler energy market, but warned the single-unit price option was "not as simple as it sounds".
Ofgem's retail markets and research partner Maxine Frerk said it did not take into account discounts for payment method, dual fuel and paperless billing.
Ms Frerk said, "Our extensive consumer research indicates that customers value these discounts, and our reforms seek to deliver simplicity while retaining the choice that consumers value".
One of the UK's biggest energy suppliers has called for petrol station-style pricing in a bid to help consumers identify the best deals.
EDF Energy, which supplies 5.5 million households and businesses, said it will implement single-unit pricing for gas and electricity if all other suppliers also committed to doing so.
It would mean that customers would only need one price - the unit price - to compare between different suppliers.
Energy prices are currently set regionally with some suppliers including a standing charge and a price for each unit of electricity and gas consumed.
Other suppliers operate a two tier pricing structure, where customers are charged a lower unit rate once a certain amount of energy has been used.