Thousands of homeowners hoping for promised power savings of up to $540 via a 1.5kW system are in limbo, with those wanting larger systems even being asked to pay more than $20,000 to help cover local upgrades.
Energex said the state's electricity network since the 1950s had been designed to deliver power from the station to the home and the voltage now heading "the other way" was causing a huge dilemma.
Following advice from engineering experts, no more systems will be automatically approved when the penetration of solar photovoltaic systems hits 30 per cent in neighbourhoods.
The penetration refers to the maximum capacity of the transformer supplying the local zone, which can include 50 homes.
In a bid to cut power bills, more than 107,000 Queensland households have jumped at the Solar Bonus Scheme, launched in 2008, exporting 72.5 million kW hours back to the grid.
However, unless significant, costly upgrades are completed, many who might want to add solar panels in the future may not be able to.