Energy Networks Australia says solar rooftop has flooded the network in Queensland.

The energy group’s CEO Andrew Dillon has warned that the state’s electricity grid was not designed to cope with the energy it now receives in the middle of the day when demand is low.

“We have almost one in three households in Queensland that have solar panels on their roof and to be honest, by world standards, that is off the chart,” Mr Dillon told ABC reporters.

“Places like Hawaii and California are more like 20 per cent so Queensland is really a world leader.

“So that's great for renewable energy generation but it's creating some real challenges for the networks operating the grid when you have that much energy coming back in in the middle of the day.”

Mr Dillon said networks are struggling to handle new technologies.

“For a while the network has operated really well to be honest, as a solar sponge being able to soak up this generation — but once we get to certain levels, if we don't start getting smarter about how we manage it, we will see some technical issues,” he said.

Mr Dillon warned that problems could occur.

“The first one is we start to get voltage and frequency issues, which can damage equipment or even localise outages,” he said.

“The second one is we have networks saying to customers wanting to connect solar; ‘No you can't do it because we're full’.”

Otherwise, networks may be left facing big bills to upgrade their facilities.

Queensland Energy Minister Dr Anthony Lynham said the state is moving to future-proof the network.

“We have to move the peak that we're seeing during the middle of the day when we have solar, to that night time cooking peak, and we're doing that,” Dr Lynham said.

“The big thing we're doing obviously is the pumped hydro, the big Wivenhoe pumped hydro storage solution. That's 570 megawatts … that's a coal-fired power station.

“So during the middle of the day when all the solar panels on roofs are working, we're storing energy through pumping water up the top of the hill at Wivenhoe and at night time we're driving it back down.”