Operators of battery storage power plants say they could cut up to €35m off energy bills on the island of Ireland this winter if they were allowed to sell electricity onto the wholesale market.
At the moment the energy storage plants are kept in reserve to provide emergency back up for the power grid.
The rise in renewable energy which does not produce power all the time and increased demands on the grid have meant energy storage plants have become important for energy security.
They are contracted to provide electricity at short notice if there is not enough regular supply to meet demand.
But now Energy Storage Ireland, which represents the operators, says they could also cut costs by bringing down peak prices for electricity.
Energy storage plants across the island have a capacity of 670MW and research commissioned by the association suggests they could cut bills in the North by €9m and in the Republic by €26m if they were allowed to sell into the grid.
The technology is there but it would require the regulators to change the rules.
The regulators say they want to see more analysis.
Bobby Smith, Head of Energy Storage Ireland, said that battery storage projects are the back-up to the electricity system, helping to ensure a secure and stable electricity grid.
But he said today's report shows they can do much more.
"The current rules block battery storage projects from selling their power. This means more gas on the system and higher bills for families this Christmas," Mr Smith said.
"With no additional investment or structural changes needed for this, change can be actioned immediately to unlock this potential cost saving for households and businesses," he added.