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Abstract: This paper describes a model of the 2020 Irish electricity system which was developed and solved in a mixed integer programming, unit commitment and economic dispatch tool called PLEXOS®. The model includes all generators on the island of Ireland, a simplified representation of the neighbouring British system including proposed wind capacity and interconnectors between the two systems. The level of wind curtailment is determined under varying levels of three influencing factors. The first factor is the amount of offshore wind, the second is the allowed limit of system non-synchronous penetration (SNSP) and the third is inclusion or exclusion of transmission constraints. A binding constraint, resulting from the 2020 EU renewable energy targets, is that 37% of generation comes from wind. When the SNSP limit was increased from 60% to 75% there was a reduction in wind curtailment from 14% to 7%, with a further reduction when the proportion of wind capacity installed offshore was increased. Wind curtailment in the range of SNSP limit of 70–100% is influenced primarily by the inclusion of transmission constraints. Large changes in the dispatch of conventional generators were also evident due to the imposition of SNSP limits and transmission constraints. [Copyright &y& Elsevier]

Abstract: This paper describes a method for quantifying wind farm availability using two different approaches and comparing the results. Wind turbine suppliers regularly guarantee turbine availability in terms of time. A typical value of 97% is generally taken as the industry standard. This paper shows that this guarantee can potentially under-compensate the wind farm operator for losses sustained depending on when the period of non-availability occurs. Here we present an alternative method to quantify wind farm availability based on energy, which relates the energy losses in an Irish wind farm in 2007 to periods of turbine non-availability. It is shown in this analysis completed at this operational wind farm that while the technical non-availability as a percentage of time is 3%, the percentage of energy lost during downtimes is actually 11%. Based on the financial analysis above, the financial losses are significant. To answer the question should wind turbine availability be time or energy based, this paper shows that it can be advantageous for wind turbine owners to have energy-based calculations as long as the developers have sufficient monitoring of not only wind speed but also SCADA data. [Copyright &y& Elsevier]

Studies focusing on 100% renewable energy systems have emerged in recent years; however, existing studies tend to focus only on the power sector using exploratory approaches. This paper therefore undertakes a whole-system approach and explores optimal pathways towards 100% renewable energy by 2050. The analysis is carried out for Ireland, which currently has the highest share of variable renewable electricity on a synchronous power system. Large numbers of scenarios are developed using the Irish TIMES model to address uncertainties. Results show that compared to decarbonization targets, focusing on renewable penetration without considering carbon capture options is significantly less cost effective in carbon mitigation. Alternative assumptions on bioenergy imports and maximum variability in power generation lead to very different energy mixes in bioenergy and electrification levels. All pathways suggest that indigenous bioenergy needs to be fully exploited and the current annual deployment rate of renewable electricity needs a boost. Pathways relying on international bioenergy imports are slightly cheaper and faces less economic and technical challenges. However, given the large future uncertainties, it is recommended that further policy considerations be given to pathways with high electrification levels as they are more robust towards uncertainties. • 100% renewable energy can be achieved by multiple pathways with similar cost levels. • Focusing only on renewables is not the most cost-effective path to decarbonization. • Pathways relying on bioenergy import are more susceptible to uncertainties. • Indigenous bioenergy needs to be exploited to its full potential. • Much greater efforts than current national action plans are required. [ABSTRACT FROM AUTHOR]