energies Article Identification of Extreme Wind Events Using a Weather Type Classification António Couto , Paula Costa and Teresa Simões *   Citation: Couto, A.; Costa, P.; Simões, T. Identification of Extreme Wind Events Using a Weather Type Classification. Energies 2021, 14, 3944. https://doi.org/10.3390/en14133944 Academic Editors: Elena García-Bustamante and Cristobal Gallego-Castillo Received: 3 May 2021 Accepted: 28 June 2021 Published: 1 July 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). LNEG—Laboratório Nacional de Energia e Geologia, 2610-999 Lisbon, Portugal; antonio.couto@lneg.pt (A.C.); paula.alexandracosta@lneg.pt (P.C.) * Correspondence: teresa.simoes@lneg.pt; Tel.: +351-21-092-4775 Abstract: The identification of extreme wind events and their driving forces are crucial to better integrating wind generation into the power system. Recent work related the occurrence of extreme wind events with some weather circulation patterns, enabling the identification of (i) wind power ramps and (ii) low-generation events as well as their intrinsic features, such as the intensity and time duration. Using Portugal as a case study, this work focuses on the application of a weather classification-type methodology to link the weather conditions with wind power generation, namely, the different types of extreme events. A long-term period is used to assess and characterize the changes in the occurrence of extreme weather events and corresponding intensity on wind power production. High variability is expected under cyclonic regimes, whereas low-generation events are most common in anticyclonic regimes. The results of the work provide significant insights regarding wind power production in Portugal, enabling an increase in its predictability. Keywords: wind power; meteorology; weather regimes; extreme events; wind power variability; wind power ramps; lower generation events 1. Introduction To mitigate climate change, the decarbonization of our society is mandatory and has been encouraged by policymakers. One of the main measures to accomplish the desired decarbonization is the transition from conventional fossil fuels to low levels or to zero-carbon renewable energy technologies, which, in combination with energy-saving measures such as higher energy efficiency, will contribute to mitigating the impacts of climate change [1]. In this sense, renewable energies such as solar photovoltaic (PV) and wind represent key elements in the energy supply, now and in the near future. As an example, according to the national energy and climate plans of European Union countries, 80% of the new installed capacity will be based on renewable energy systems, namely, wind technology (onshore and offshore), which may become the main source of energy in the coming decades [2]. In the Portuguese case, this technology will increase from the current 5.4 GW to 9.3 GW (9.0 GW onshore and 0.3 offshore) [2]. Despite the environmental benefits of renewable energy sources, their weather-depen- dent nature and the intrinsic time and spatial variability of primary resources, as well as their poor predictability, often hinders their integration into power systems, especially when integrated on a large scale. This behavior differs from conventional power plants (e.g., coal, natural gas, and hydroelectric power plants), which can be easily managed to counterbalance, each time, the electricity demand to keep the power system stable. Conversely, taking into account the emergence of nearly 100% renewable energy systems, the conventional/fossil power plants tend to disappear, and with them, their support of flexibility needs. On the other hand, in some regions such as in the Iberian Peninsula, the impact of climate change will definitely change the water cycle, which affects precip- itation and, consequently, the availability of hydro generation, increasing dependency on wind and solar power generation. Therefore, a long-term comprehensive approach, Energies 2021, 14, 3944. https://doi.org/10.3390/en14133944 https://www.mdpi.com/journal/energies