The Impact of the North Atlantic Oscillation on Renewable Energy Resources in Southwestern Europe

TLDR

Europe is heavily investing in renewable energy, yet the link between large‑scale climate modes and renewable resource variability in Iberia remains unclear. The study aims to assess how the North Atlantic Oscillation influences interannual variability of Iberia’s main renewable energy resources. The authors use a 10‑km resolution climate simulation (1959–2007) and analyze how orography and wind direction modulate NAO effects on renewable resources. Negative NAO phases boost Iberian wind and hydropower by 10–15 % and >100 % respectively, reduce solar output by 10–20 %, and these patterns are confirmed by real generation data.

Abstract

Abstract Europe is investing considerably in renewable energies for a sustainable future, with both Iberian countries (Portugal and Spain) promoting significantly new hydropower, wind, and solar plants. The climate variability in this area is highly controlled by just a few large-scale teleconnection modes. However, the relationship between these modes and the renewable climate-dependent energy resources has not yet been established in detail. The objective of this study is to evaluate the impact of the North Atlantic Oscillation (NAO) on the interannual variability of the main and primary renewable energy resources in Iberia. This is achieved through a holistic assessment that is based on a 10-km-resolution climate simulation spanning the period 1959–2007 that provides physically consistent data of the various magnitudes involved. A monthly analysis for the extended winter (October–March) months shows that negative NAO phases enhance wind speeds (10%–15%) and, thereby, wind power (estimated around 30% at typical wind-turbine altitudes) and hydropower resources (with changes in precipitation exceeding 100% and implying prolonged responses in reservoir storage and release throughout the year), while diminishing the solar potential (10%–20%). Opposite signals were also sporadically identified, being well explained when taking into account the orography and the prevailing wind direction during both NAO phases. An additional analysis using real wind, hydropower, and solar power generation data further confirms the strong signature of the NAO.