Coping with the Dunkelflaute: Power system implications of variable renewable energy droughts in Europe

Coping with the Dunkelflaute: Power system implications of variable renewable energy droughts in Europe | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Coping with the Dunkelflaute: Power system implications of variable renewable energy droughts in Europe Martin Kittel, Alexander Roth, Wolf-Peter Schill This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5760653/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 09 May, 2026 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Abstract Coping with prolonged periods of low availability of wind and solar power, also referred to as "Dunkelflaute", emerges as a key challenge for realizing a decarbonized European energy system fully based on renewable energy sources. Here we investigate the role of long-duration electricity storage and geographical balancing in dealing with such variable renewable energy droughts. To this end, we combine renewable availability time series analysis and power sector modeling, using 36 historical weather years. We find that extreme drought events define long-duration storage operation and investment. The most extreme event in Europe occurred in the winter of 1996/97. Assuming policy-relevant interconnection, long-duration storage of 351TWh or 7% of yearly electricity demand is required to deal with this event. As it affects many countries simultaneously, a storage capacity of 159 TWh or 3% of yearly electricity demand remains required even in the extreme case of unconstrained geographical balancing. Before and during Dunkelflaute events, we find complex interactions of long-duration storage with other flexibility options. Sensitivity analyses illustrate that firm zero-emission generation technologies would only moderately reduce long-duration storage needs. Thus, policymakers and system planners should prepare for a rapid expansion of long-duration storage capacity to safeguard the renewable energy transition in Europe. We further argue that using multiple weather years that include pronounced renewable energy droughts is required for weather-resilient energy system modeling. Scientific community and society/Energy and society/Energy supply and demand Scientific community and society/Energy and society/Energy economics Earth and environmental sciences/Environmental social sciences/Energy and society/Energy security variable renewable energy variable renewable energy droughts long-duration storage power sector modeling Full Text Additional Declarations There is NO Competing Interest. Cite Share Download PDF Status: Published Journal Publication published 09 May, 2026 Read the published version in Nature Communications → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5760653","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":403692018,"identity":"bc7b4f47-7111-4bef-9b4e-2c8d1afef070","order_by":0,"name":"Martin Kittel","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAqklEQVRIiWNgGAWjYDACHsYGIGkhx3AYxCFSS2PDAQYJY1K0MDCCtCQCCSK16PYcbn/8oUIive84jwHDmwoitJidbQQ67IxE7szDPAaMc84Qo+U80C8H2yRyNxzm3cDM20a0ln8S6QZgLf+IddjBBokEiJYGYrScOdg448wxCcOZh/k/HJxzjCgt6Q8+VNTYyPOdP5b44E0NEVpQwAFSNYyCUTAKRsEowAEAtJY96cvT40EAAAAASUVORK5CYII=","orcid":"","institution":"German Institute for Economic Research (DIW Berlin)","correspondingAuthor":true,"prefix":"","firstName":"Martin","middleName":"","lastName":"Kittel","suffix":""},{"id":403692019,"identity":"02a2246d-1d0b-4a1d-b944-e0696a9063f5","order_by":1,"name":"Alexander Roth","email":"","orcid":"","institution":"German Institute for Economic Research (DIW Berlin)","correspondingAuthor":false,"prefix":"","firstName":"Alexander","middleName":"","lastName":"Roth","suffix":""},{"id":403692020,"identity":"dae97c3b-b4f9-421f-9fbe-4d6b42863c67","order_by":2,"name":"Wolf-Peter Schill","email":"","orcid":"https://orcid.org/0000-0002-6981-7487","institution":"German Institute for Economic Research (DIW Berlin)","correspondingAuthor":false,"prefix":"","firstName":"Wolf-Peter","middleName":"","lastName":"Schill","suffix":""}],"badges":[],"createdAt":"2025-01-03 23:05:06","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5760653/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5760653/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1038/s41467-026-72681-5","type":"published","date":"2026-05-09T04:00:00+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":108898184,"identity":"eec321a0-d736-4ede-9f6c-05680d8ad1e9","added_by":"auto","created_at":"2026-05-10 07:05:45","extension":"pdf","order_by":1,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":6061545,"visible":true,"origin":"","legend":"Article File","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5760653/v1_covered_7fd8b078-f823-4618-b244-a1233373ef2c.pdf"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Coping with the Dunkelflaute: Power system implications of variable renewable energy droughts in Europe","fulltext":[],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":false,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":true,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":true,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"nature-portfolio","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"","title":"Nature Portfolio","twitterHandle":"","acdcEnabled":false,"dfaEnabled":false,"editorialSystem":"ejp","reportingPortfolio":"","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"variable renewable energy, variable renewable energy droughts, long-duration storage, power sector modeling","lastPublishedDoi":"10.21203/rs.3.rs-5760653/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5760653/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Coping with prolonged periods of low availability of wind and solar power, also referred to as \"Dunkelflaute\", emerges as a key challenge for realizing a decarbonized European energy system fully based on renewable energy sources. Here we investigate the role of long-duration electricity storage and geographical balancing in dealing with such variable renewable energy droughts. To this end, we combine renewable availability time series analysis and power sector modeling, using 36 historical weather years. We find that extreme drought events define long-duration storage operation and investment. The most extreme event in Europe occurred in the winter of 1996/97. Assuming policy-relevant interconnection, long-duration storage of 351TWh or 7% of yearly electricity demand is required to deal with this event. As it affects many countries simultaneously, a storage capacity of 159 TWh or 3% of yearly electricity demand remains required even in the extreme case of unconstrained geographical balancing. Before and during Dunkelflaute events, we find complex interactions of long-duration storage with other flexibility options. Sensitivity analyses illustrate that firm zero-emission generation technologies would only moderately reduce long-duration storage needs. Thus, policymakers and system planners should prepare for a rapid expansion of long-duration storage capacity to safeguard the renewable energy transition in Europe. We further argue that using multiple weather years that include pronounced renewable energy droughts is required for weather-resilient energy system modeling.","manuscriptTitle":"Coping with the Dunkelflaute: Power system implications of variable renewable energy droughts in Europe","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-01-20 02:15:58","doi":"10.21203/rs.3.rs-5760653/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"nature-communications","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"NCOMMS","sideBox":"Learn more about [Nature Communications](http://www.nature.com/ncomms/)","snPcode":"","submissionUrl":"https://mts-ncomms.nature.com/","title":"Nature Communications","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Nature Communications","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"1d305446-cd90-44ec-8023-8fe1248c3bd6","owner":[],"postedDate":"January 20th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":43045432,"name":"Scientific community and society/Energy and society/Energy supply and demand"},{"id":43045433,"name":"Scientific community and society/Energy and society/Energy economics"},{"id":43045434,"name":"Earth and environmental sciences/Environmental social sciences/Energy and society/Energy security"}],"tags":[],"updatedAt":"2026-05-10T07:05:29+00:00","versionOfRecord":{"articleIdentity":"rs-5760653","link":"https://doi.org/10.1038/s41467-026-72681-5","journal":{"identity":"nature-communications","isVorOnly":false,"title":"Nature Communications"},"publishedOn":"2026-05-09 04:00:00","publishedOnDateReadable":"May 9th, 2026"},"versionCreatedAt":"2025-01-20 02:15:58","video":"","vorDoi":"10.1038/s41467-026-72681-5","vorDoiUrl":"https://doi.org/10.1038/s41467-026-72681-5","workflowStages":[]},"version":"v1","identity":"rs-5760653","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5760653","identity":"rs-5760653","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}