Call to cut pre-payment meter charges by Ofgem
Some energy suppliers charge customers up to £180 to install and remove pre-payment meters from homes.
These meters require tokens to be bought or a card loaded with funds before gas and electricity is used in the property.
Energy regulator Ofgem found that 40% of suppliers charged for installation of meters and 5% charged for removal, while the others did so free of charge.
It wants these charges to be abolished by the autumn.
"Ofgem is concerned that charges and costs for using a pre-payment meter fall on those least able to afford them," said Philip Cullum, of Ofgem.
"That is why we want to remove barriers, deliver greater protections and offer more choice for pre-payment customers to ensure they are able to find the best possible deals."
It found charges could reach £180 for installation and £160 for removal.
Gillian Guy, chief executive of Citizens Advice, said: "Pre-pay energy consumers pay more for a second-rate service. Too many pre-pay customers can also feel locked out of the best deals by unfair charges."
Last month, figures obtained by BBC Radio 5 live revealed that more than 500,000 pre-payment energy meters had been forcibly installed in people's homes over the last six years.
Energy suppliers can gain a court order to install a pre-pay meter when customers run up debt. Ofgem said it would investigate after the figures - for England, Scotland and Wales - were released.
The Competition and Markets Authority (CMA) is expected to publish the initial findings of its investigation into the energy market soon.