The Republic of Ireland and Northern Ireland have ambitious targets for 40% of electricity
to be supplied by renewables by 2020, with the majority expected to be supplied by
wind power. There is, however, already a significant amount of wind power being turned
down, or ‘curtailed’, and this is expected to grow as wind penetrations increase.
A model-based approach is taken to estimate curtailment using high-resolution wind
speed and demand data covering four years, with a particular focus on the temporal
characteristics of curtailment and factors that affect it. The model is validated
using actual wind output and curtailment data from 2011. The results for 2020 are
consistent with previously published estimates, and indicate curtailment levels ranging
from 5.6 to 8.5% depending on assumptions examined in this study. Curtailment is found
to occur predominantly at night, and to exhibit stochastic variability related to
wind output. To accommodate high penetrations of wind power, the findings highlight
the value of flexible demand over relatively long time-periods. The model's output
data have been made publicly available for free for further investigation.