Atlantic Storm Claudia cuts solar irradiance across Western Europe

Storm Claudia, which hit Western Europe in mid-November, brought damaging winds and widespread power disruptions across the Iberian Peninsula and British Isles. Severe weather associated with the Atlantic storm system reduced solar irradiance and damaged solar assets, causing widespread power outages. Whilst the impacts of significant weather events like Storm Claudia are worst felt in lives lost and damage done, the resilience of renewable-powered grids to severe weather is a key factor in the widespread community impacts from storms. Renewable power generators, grid and system operators, and those with residential or large-scale solar systems, need to be aware of upcoming weather events and how to prepare for them to minimize negative impacts.

Storm Claudia developed as a deep low-pressure system over the North Atlantic, and was identified and named on November 10 before tracking east toward Europe. Its associated frontal systems delivered strong winds and flooding rain to Ireland, England, and Wales on the 13th and 14th, while Portugal, Spain, and the Canary Islands endured severe conditions from the 12th to the 16th. Heavy and widespread cloud cover during this period sharply reduced daily irradiance across the British Isles and the Iberian Peninsula, limiting solar generation. On November 15, solar irradiance estimates based on satellite imagery showed low GHI due to dense storm cloud centered northwest of Portugal, casting a broad shadow over key solar regions.

The storm caused extensive physical and infrastructural damage. In Portugal, the town of Albufeira was hit by a tornado on 15 November, resulting in one fatality at a campground and multiple injuries at a nearby hotel. Across the region, thousands of households experienced power outages as trees, their roots destabilized by saturated soils, fell onto power lines. Reports cited over 20,000 customers without power in Portugal alone, with additional outages across Ireland, England, France and Spain.

Notwithstanding the significant personal toll and costs incurred by these damages, management of power supply in the lead up to these events is key to limiting the scale of negative impacts. Increasing residential storage capacity and the proliferation of hybrid solar-plus-storage plants offer a mitigation opportunity through storing power ahead of severe weather events. Forecasting of severe weather events can allow owners and operators of batteries of any scale to adopt conservative battery strategies and provide power.

The above data shows the severe weather index maximum for November 15, and a time series of severe weather index for Albufeira in the days leading up to the tornado. During Storm Claudia, this index showed sustained elevated values in affected areas, including Albufeira, indicating increased risk of dangerous weather. The extended period of a high severe weather index indicated early that damaging winds were likely. This, combined with an irradiance forecast for the region, could be used to predict a long-term period of reduced solar generation.

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