Smart meters will allow energy firms to introduce "surge pricing" to charge households more for gas and electric at peak times, a former senior Ofgem manager has warned.
So-called "time of use" tariffs would see households pay more for watching television, charging gadgets and running the washing machine during popular times such as in the mornings and evenings.
The controversial deals would see energy prices peak on special events like Christmas Day and Easter when millions of households are all using ovens to cooking lunch at the same time.
Under the Government's £11bn smart meter roll out every home in the UK will be offered a smart meter by 2020, in an effort to help people save money and use less energy.
Unlike ordinary meters, smart meters transmit information about when households use most energy to suppliers. At present customers will smart meters are charged a flat fee per unit of energy used.
According to Jerry Fulton, former head of gas and electric meter meterology at Ofgem, the energy regulator, the introduction of smart meters will soon give suppliers the power to increase bills at busy times, just like paying off-peak and peak time travel.
He told the Daily Telegraph: "I believe that the hidden agenda behind smart meters is that they will allow half-hourly charging.
"Instead of having two charge rates (day and night) the price of energy will change every half hour, so when solar and wind generation are low and usage is high the price of electricity will rise steeply.
"What would make more sense than smart meters is smart appliances that could be automatically switched on or off depending on electricity-grid demand. For instance, fridges, freezers and some battery chargers could be switched off at peak demand periods, as could some washing machines and dryers.
"It is claimed that smart meters are safe and secure. Not having one, because they are not needed, is even more safe and secure."
Switching service USwitch has also said that "time of use" energy deals will become commonplace once the Government's smart meter rollout is complete.
Such deals will begin to dominate the energy market once so-called "second generation" smart meters have been installed in people's homes, it said.
Energy firms have said they would be open to introducing such tariffs as an option alongside normal tariffs.
Mr Fulton added that switching to a cheaper deal would become "a complete nightmare" once time of day tariffs have been introduced, as fluctuating prices would be difficult to compare.
Last week this newspaper revealed that Britain's biggest energy firms are failing to tell customers with smart meters that they will stop working if they switch to a cheaper deal.
Just over half of the one million households with a smart meter who change energy providers every year to save money find the device goes "dumb", data shows.
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