Solar farms in the UK have been paid to switch off so a surge of sun doesn't overwhelm the grid, research shows. Overseen by Energy Secreatary Ed Miliband, the National Energy System Operator (NESO) has issued switch-off orders since February.

Solar operators can claim compensation when forced to switch off by NESO, which manages Britain's power grids. NESO has said such action is required to ensure UK power grids remain stable.

The cost of so-called "constraint payments" is added to householders and businesses' energy bills. Such payments apply to wind farms as well.

Britain has spent more than £670million switching off wind turbines and paying gas plants to switch on, according to the Wasted Wind website, which recommends improving the grid and making energy cheaper where supplies are strong.

Five solar farms were paid a total of £102,500 to cut output by 3.6 gigawatt hours between February and June this year.

The figure comes from research by the Renewable Energy Foundation (REF). The energy data charity's director, John Constable, told the Telegraph the amount is set to grow.

He said renewables developers should be able to stand on their own feet by now but they are still begging for subsidies and special treatment, such as constraint payments.

Mr Constable added: "It's a key reason why the UK has some of the world's highest energy prices. It's time for this to stop before the burden on households and businesses does irreparable harm."

A spokesman from NESO said: "When there are physical constraints on the network and it cannot physically transfer the power from one region to another, we sometimes ask [solar] generators to reduce their output to maintain system stability and manage the flows on the network.

"Generators are then compensated via a constraint payment. We don't comment on individual assets or the costs paid to them."

A spokesman from the Department for Energy Security and Net Zero said some solar farms were recently given their first constraint payments. He said the Government is working "at pace" with the industry to rewire the UK, minimise constraint payments and speed up construction of grid infrastructure.

Chris Hewett, Chief Executive of trade body Solar Energy UK, said there are now more than 3,300 solar farms across the UK and that only five of these being in receipt of constraint payments showed the issue is of limited significance. He added, however, that it does underline the grid needs more energy storage.