Why turn a wind turbine down?
Available wind energy and electricity accepted by the grid are not always the same. Sometimes output has to be reduced.
Reviewed 2 November 2026 · Republic of Ireland
The grid has limits
Supply and demand have to stay balanced, and electricity has to travel through a network with finite capacity. The ability to manage renewable output depends on the whole system, not just on whether wind is available at one turbine.
Constraint and curtailment are different
A network constraint is local: a section of the network cannot safely carry all the power that would otherwise be produced. System-wide curtailment concerns the amount of renewable generation the system can safely manage. Oversupply can also arise when available generation exceeds demand and the available outlets for that electricity.
Dispatch-down is the wider reporting term for reductions in renewable output. EirGrid publishes dedicated dispatch-down reports; those are the appropriate source for measured losses and their causes.
A low reading does not explain its cause
The index shows reported generation, not all the wind energy that might have been available. A low value could reflect weather or operational factors. The difference between a forecast and actual output is not, by itself, a measurement of curtailment.
Understanding an event needs the relevant operational evidence. We do not calculate a curtailment total from this dashboard’s wind-to-demand ratio.