ENERGY industry players have dismissed a call for a major investigation into a “rip-off racket” by wind power firms in Scotland.

The GMB union, which represents workers in the sector, wants a probe into “bonkers” subsidies for renewables and is calling for changes to benefit bill payers.

Citing figures from the Renewable Energy Foundation, it claims consumers have paid £328 million to wind farm owners since 2010 due to compensation for periods when the National Grid tells them to switch off turbines.

The order comes when the energy grid reaches capacity, with wind farm owners granted “constraint payments” funded through a surcharged levied on bill payers in a system regulated by Ofgem Claiming some firms profit through overcharging, GMB calls this a “rip-off racket centred in Scotland”, where most of the UK’s onshore wind developments are sited, and wants the Government to scrap the system and use general taxation to fund the payments instead.

The union’s national energy secretary Justin Bowden said: “The public are being milked by paying twice over – through spiralling consumer energy bills and taxpayer hand-outs.”

But key industry players dispute GMB’s claims, with Ofgem saying rules against overcharging have been in place for five years and payments down “significantly”. A spokesperson said: “In 2012, the average price that generators charged to reduce their output during constraints was £204 per megawatt hour (MWh). By the end of 2016 the price had fallen to £66/MWh.”

Michael Rieley of umbrella body Scottish Renewables said Westminster figures show onshore wind and solar are “the cheapest sources of new power generation”, adding: “Bringing more renewable energy on to the grid helps keep household bills lower than they otherwise would be and reduces the harmful carbon emissions which cause climate change.

“National Grid’s job is to flex generation around the constraints in our energy infrastructure and ensure supply meets demand. Robust measures to control the cost of these actions are already in place, and as investment is made in our electricity transmission system these costs will fall.

“Scotland has a long history of renewable energy generation and has the lion’s share of the UK’s resource. Developing green energy here makes economic, social and environmental sense.”

Meanwhile, the Department for Business, Energy and Industrial Strategy said: “Social and environmental policies make up a small proportion of bills.

“Our transition to a low-carbon economy through our ambitious Industrial Strategy and Smart Systems Plan means that the costs of delivering renewable energy will continue to fall over time.”