Wind farms operators were paid £900,000 by the National Grid to disconnect their turbines for one night because the electricity was not needed.
The payments, worth up to 20 times the value of the power they would have produced, raises serious concerns about such subsidies, which are paid for by the customer.
The six Scottish wind farms were asked to stop producing electricity on a particularly windy night last month as the National Grid was overloaded.
Their transition cables do not have the capacity to transfer the power to England and so they were switched off and the operators received compensation. One operator received £312,000, while another benefited by £263,000.