Electricity industry leaders are arguing that 'unfair' National Grid charges are putting tens of thousands of jobs at risk.
In a letter seen by the Times, industry leaders have told politicians that high charges for electricity transmission may delay or even prevent some renewable electricity generation projects.
Nick Horler, chief executive of Scottish Power, and Ian Marchant, chief executive of Scottish and Southern Energy, signed the letter, which reads: "The transmission charges are making our renewables strategy more expensive, as well as putting at risk the full development of a key natural resource."
The letter was sent to leaders of all parties represented in the Scottish Parliament. Scottish energy minister Jim Mather said: "We will be calling on Parliament this week to support us in securing change."
Scottish companies face the highest electricity transmission charges in the UK, as they are calculated according to how far an area is from the place of highest demand, London.