The city of Rotterdam in the Netherlands has emerged as a leader in energy transition and circular economy initiatives. With a strong focus on sustainability, Rotterdam has become a hub for innovative projects and collaborations. The city's extensive energy ecosystem, in partnership with research institutions, is driving the development of a state-of-the-art hydrogen value chain, including projects for green and blue hydrogen production. Rotterdam is also at the forefront of sustainable transport, with initiatives like hydrogen-powered water taxis and a focus on circular economy sectors like construction and healthcare. Rotterdam's collaborative approach between government, businesses, and research institutions has led to successful programs like the Rotterdam Offshore Wind Coalition and the Smart Energy Systems Programme. The city has a clear roadmap for the Circular Economy, aiming to significantly reduce the use of raw materials by 2030. Initiatives like BlueCity support circular companies and startups working towards environmental sustainability. Several startups in Rotterdam are driving innovation in energy transition and circular economy. Companies like Battolyser Systems, Solarduck, Gradyent, and Rocsys are developing cutting-edge technologies in areas such as energy storage, offshore floating solar solutions, digital twin platforms, and hands-free charging for electric vehicles. Supported by organizations like Up!Rotterdam, these startups are crucial in accelerating the adoption of sustainable practices in the region.