National Grid Electricity System Operator (ESO) has given an early view of expected electricity supply margins over the coming winter ahead of its usual Winter Outlook released each Autumn. The ESO has forecast a de-rated margin 4GW - or 6.7% - representing a slight increase on the 3.9GW – or 6.6% - margin predicted for last winter. However, this forecast assumes there is no disruption gas supplies and Great Britain is able attract 5.7GW of interconnector imports from the rest of Europe during tight periods.