Christian Breyer is Professor for Solar Economy at LUT University, Finland. His major expertise is the integrated research of technological and economic characteristics of renewable energy systems specialising in energy system modeling for 100% renewable energy, on a local but also global scale. His team published the most studies on 100% renewable energy systems for countries or major regions globally. Energy system transition studies are carried out in full hourly and high geo-spatial resolution.Publications cover integrated sector analyses with power, heat, transport, desalination, industry and negative CO2 emission options. Power-to-X investigations is a core research field for his team. He published more than 300 scientific papers, thereof more than 150 in scientific journals. As of September 2022 he has 170 Scopus listed publications, received more than 7800 citations (Scopus) with an h-index of 50 (Scopus) and more than 13700 citations (Google Scholar) and an h-index of 67 (Google Scholar).He worked previously for Reiner Lemoine Institut, Berlin, and Q-Cells (now: Hanwha Q Cells). He is member of ETIP PV, IEA-PVPS, scientific committee of the EU PVSEC and IRES, scientific advisory board of CO2 Value Europe, academic council of Global Alliance Powerfuels, chairman for renewable energy at the Energy Watch Group, reviewer for the IPCC and a co-founder of the Desertec Foundation. His academic background is general business, physics and energy systems engineering and a PhD in electrical engineering. He communicates in Twitter @ChristianOnRE.