If Ireland’s electricity system operates as an island, then Donegal is nearly an island within it. The county has just three lines connecting it to the rest of the Irish grid, with limited capacity, yet it is one of the windiest places in the world and has attracted wind farm developers for many years. “As a result of this relative isolation from the rest of the all-island network, Co Donegal has seen some of the highest levels of renewable constraint in Ireland historically,” Baringa consultants wrote in a new report for the industry group Energy Storage Ireland and presented at…