Executives from the National Grid have warned of blackouts before 2030 unless the South-east pays more for power.
The grid's Electricity System Operator (ESO) have been in private talks with the energy industry, with one source claiming that "there will be blackouts in the South-east by 2028."
The ESO on Tuesday said that its official position did not predict blackouts in 2028, but declined to comment on the private remarks.
A spokesman said: “As a prudent system operator we regularly assess the future challenges to decarbonising Great Britain’s electricity system whilst maintaining security of supply and managing cost.
“The ESO’s analysis does not show there will be blackouts because of current market arrangements.
“It indicates that we will need to continue to use our operational toolkit to balance the electricity system on a national basis.
“However, we expect that reforms to the wholesale electricity market, the accelerated delivery of electricity networks, and delivery of new generation and storage, will create a more efficient electricity system for the future.”
The Government's 2030 net zero target is set to push electricity supplies from renewables to a high before the end of the decade.
However, with the majority of offshore wind farms being built from the main areas of demand like London, a massive investment in grid infrastructure is needed to ensure power can be moved efficiently around the country.
The ESO have argued that because Britain currently operates as a one electricity market, the reality of shifting power from North to South will become increasingly difficult.
Jason Mann, an energy expert at FTI Consulting, said that balancing the South-east would become increasingly tough as the grid grows more constrained.
“As we go to a more intermittent renewables-based system, the challenges of balancing the grid are only going to become greater, particularly under the current national pricing regime,” he said.
The ESO is understood to have urged the Government to adopt zonal pricing.
On Tuesday, a spokesman said: “The ESO’s analysis in respect of zonal pricing supports the strategic build out and operation of Britain’s electricity system in a manner that is efficient and ensures that all networks and assets are utilised to their maximum.”