# Potential of Onshore Wind Turbine Inertia in Decarbonising the Future Irish Energy System
## 3 Scenario and Data of the Irish Energy Dispatch Model  
To assess the potential of wind inertia in the all-Island Irish power system, the before introduced methods are applied to build a unit commitment and economic inertia dispatch model, implementing minimum inertia constraints and SI provided by WTs. Great Britain and France are modelled as well to account for cross border flows with the all-Island Irish system. Since these countries are connected to the Irish system via HVDC interconnectors, inertia is not modelled and these countries are not presented in further detail. However, scenario and data sources for France and Great Britain presented hereafter are the same as for the Irish system. The scenario applied in this work is based on the 2020 Ten-Year Network Development Plan (TYNDP) of the European Network of Transmission System Operators for Electricity (ENTSO-E) [35; 36]. The National Trends (NT) scenario reflects the individual commitments and policies of each single member state to meet CO\({}_{2}\) emission reduction targets. The  
Figure 2: Two step methodology to determine \(H_{var}/H_{dem}\) applying the normalised power vs. normalised rotational speed characteristic of the NREL 5 MW WT [34] and the normalised characteristics of the variable H controller [19]. influence of the EU is reduced to a minimum in favor of national sovereignty. The power sector in particular experiences a high growth in PV and WT generation. Large scale battery energy storage solutions are limited. Coal fired generation units are replaced by gas-fired and nuclear solutions. To a large extend, data is provided by the 2020 TYNDP of the ENTSO-E [35, 37, 38]. Installed capacities per generation type, commodity and emission costs are depicted in Table 2. Characteristics of conventional thermal generators like Operation and Maintenance (O&M) costs, the efficiency and minimum stable operation values are listed in Table 3[38]. Each generator is assigned with an inertia constant based on literature review [16, 39, 40, 41, 42, 43, 44]. Feed-in from WTs and PVs is modelled via fixed power factor generation profiles in hourly resolution derived from the Pan-European Climate Database [45]. The WT power factor is also used to determine the variable inertia provided as depicted in Figure 2. Hydro inflow for run-of-river is available in a daily time resolution and on a weekly base for hydro reservoir and open loop pump storage [45]. Such inflow profiles are transformed to hourly profiles. Two modelling parameters are varied per optimisation run to assess the influence and potential of SI provided by WTs. First, the demanded inertia constant, \(H_{dem}\), which determines the actual provided SI of WTs [19]. Second, the ROCOF threshold which determines the minimum synchronous system inertia applied to create the constraint depicted in Equation (6) and remaining demand for system SI. In former grid codes, the TSO of Hydro-Quebec requested WTs to emulate a synchronous generator with an inertia constant of 3.5 s and 5 s respectively [5, 6]. These two values are applied in this work as well. The Irish grid operator already defines a ROCOF threshold of 1 Hz/s [8]. A 2 Hz/s threshold is considered as well based on recommendations of the ENTSO-E regarding ROCOF withstand capabilities of power generating modules [46]. The resulting minimum synchronous system inertia defined in Equation (6) is calculated by solving Equation (1) for \(f_{sys}\). Therefore, the loss of the largest infeed of 700 MW is used [16]. The overall minimum system inertia applied to create the constraint depicted in Equation (7) is based on system security specifications of Irish TSO. The TSO