Josef Kastner is CEO and Partner at Nexun, a pan-European platform developing solar, battery storage, and hybrid wind projects across Austria, France, Germany, Italy, Poland, and Spain.
He brings over two decades of experience across the renewable energy value chain, from project development and EPC delivery to M&A and financing. Before founding Nexun, Josef spent eight years as CEO Europe at ReneSola, where he led business development on a photovoltaic pipeline spanning Poland, France, Germany, Hungary, Spain, the UK, Italy, and Turkey, including over 170MW of solar awarded in Polish auctions, alongside origination and execution of the company’s M&A activity across Europe.
Earlier in his career, Josef led the Renewable Energy business unit at Alpine-Energie, overseeing EPC and project development across wind, solar, and biomass in more than half a dozen European markets, including the installation and maintenance of over 800MW of wind capacity for turbine manufacturers such as Vestas, Nordex, and Senvion.
With hands-on experience developing, financing, and building solar and hybrid projects across nearly every major CEE and Western European market, Josef brings a rare pan-regional perspective to conversations on scaling solar-plus-storage in Central and Eastern Europe.
