Clean Cities recognizes the most innovative European start-ups in the field of urban sustainability
Innovative and high-potential start-ups, graduated from the fifth edition of Clean Cities Spain ClimAccelerator, joined at an event that generated over 100 connections. This programme has supported over 100 start-ups from more than 20 European countries since 2021.
08.01.2026
The climate challenges we face as a society cannot be solved by focusing on public and private actors in isolation. Collaboration is key to achieving the European climate targets for 2030 but, how can we strengthen it between different government agencies and private entities?
One way is through in-person events like the Clean Cities Demo Day, which took place this month at Madrid. The event marked the culmination of the programme, supported by Climate KIC, which included polished pitches from selected European start-ups in this edition. Investors, corporates, city councils, and experts linked to business and sustainability convened under a common interest: scaling companies to advance climate commitments.
The fifth edition of the programme, which ran throughout 2025, focused on supporting start-ups in areas such as investment, scalability, internationalisation, and sustainability. In total, eighty applications from twenty four countries were submitted, and ultimately, fifteen start-ups were selected to participate. For nine months, the participating start-ups received a comprehensive 40-hour training programme, attended three leading international events on entrepreneurship and sustainable cities, and participated in mentoring sessions with experts from diverse fields such as business, sustainability, AI, construction, and more. A total of 16 mentors from more than seven different countries provided more than 200 hours of guidance to founders with solutions focused on climate neutrality across all city systems.
The results speak for themselves
Globally, this accelerator programme contributes more than100 start-ups from 20 countries within the deep-tech ecosystem for sustainable cities. These startups have a Technology Readiness Level (TRL) of 7 to 9, and more than 50 per cent of them have launched a new product or service. Since its inception, this initiative has attracted over 350 applications.
Over the past five years, the start-ups in the Clean Cities Spain ClimAccelerator programme have secured nearly €30 million in funding annually. Furthermore, more than 25 European partners have supported the development of this accelerator, which has involved over 200 experts from the public and private sectors in fields such as technology, business, investment, sustainability, and internationalization.
New 2026 edition now underway
The sixth edition of the acceleration programme will launch in January of next year, welcoming new European start-ups developing solutions to urban challenges. The application will be available on the program's website (https://cleancities-accelerator.com/).
The next edition will continue to focus on strengthening connections with the urban ecosystem through mentoring international experts in key areas such as technology, business, and investment, among others.
Currently, this initiative employs a multi-level, multi-stakeholder approach, always from a systemic perspective. Therefore, several organisations actively support this accelerator. From the public sector: Madrid City Council, Valencia City Council, Segovia City Council, Zaragoza City of Knowledge Foundation, and the Center for Innovation in Circular Economy. From the private sector: companies such as Ferrovial, CREA Madrid Nuevo Norte, Amadeus Nexwave, and SMEs such as Zubilabs and Vranded Haus.
About Clean Cities Spain ClimAccelerator
Clean Cities Spain ClimAccelerator is an acceleration programme launched in 2020 with the support of Climate KIC, aiming to impact climate change in urban areas and commercialise clean technologies (clean tech). The programme is aimed at start-ups developing solutions with a special emphasis on transforming urban ecosystems to be climate-neutral, from mobility to waste, energy, and health. The Clean Cities community already comprises more than 100 start-ups from over 20 countries.
About the Universidad Politécnica de Madrid (UPM)
UPM is placed amongst the 25% of the best higher education institutions worldwide and the first Spanish technical university. This University is characterized by a strong commitment to the SDGs and is working towards a climate-neutral campus by 2040. The Entrepreneurship Unit aims to stimulate innovation within the technological ecosystem. To this end, it has created and developed an "open technological ecosystem" linked to the development of technology-based products and processes, resulting in the creation of 336 high-tech startups and the raising of over €250 million in recent years. Based on this premise, the University carries out activities that include entrepreneurship training and the incubation and acceleration of startups.
Climate KIC is Europe’s leading climate innovation agency and community, creating climate-resilient communities and fighting climate breakdown by mobilising systems change in countries, regions, cities, and businesses. Together with partners across the globe, Climate KIC orchestrates solutions and facilitates learning to bridge the gap between climate commitments and current reality, driving faster and more ambitious action.
Founded in 2010 upon the initiative of the European Institute of Innovation and Technology (EIT) (a body of the European Union), Climate KIC received funding and strategic guidance for over 15 years as an EIT Knowledge and Innovation Community (KIC). Today, as an independent foundation, Climate KIC continues to collaborate with EIT and other EU institutions, as well as intergovernmental organisations, UN agencies, national and regional governments, cities, civil society, academia and the private sector to boost climate innovation across Europe and beyond.
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