The LEAP Ireland model is a medium-term, aggregated multi-sectoral model of energy demand and supply for Ireland. It models in detail all sectors of the economy (transport, resident, industry, services) and the electricity generation sector; the LEAP Ireland model is built with input from ArDEM, the Car Stock Model and the electricity system models. On the demand side, the purpose of the LEAP Ireland model is to examine the impact of individual energy efficiency policies (e.g. residential retrofit scheme, electric vehicles) as well as aggregated packages of policies (e.g. National Energy Efficiency Action Plan). On the supply side (i.e. the electricity generation sector), the model uses the linear programming optimisation features of the Open Source Energy Modelling System (OSeMOSYS) to calculate the least-cost solution for electricity system dispatch and capacity expansion.