Ireland has a 32-county electricity system, courtesy of the interconnected all-island transmission grid and a single wholesale power market.

Electricity is unusual. Demand must be met with (more or less) instantaneous supply, since electricity cannot easily be stored. If you fancy an ice cream, somebody in the supply chain has kept stock in the freezer that was produced days, weeks or months ago and there is no need for an ice-cream plant to click into action to coincide with your whim.