European cities share many challenges when it comes to meeting their climate goals – and through the EU Cities Mission, they are working together to solve them and learning from each other’s successes. Irene Vivas Lalinde, a city support officer from NetZeroCities’ partner Eurocities, writes here about how two in particular – Cologne and Soria – are replicating innovative models to speed up the transformation on energy use and efficiency.

Rapidly decarbonising the built environment in an equitable manner is a huge challenge for many European cities. This challenge includes implementation of the EU’s Energy Performance of Buildings Directive and, in particular, article 18, stipulating that Member States “ensure the establishment and the operation of technical assistance facilities, including through inclusive one-stop shops for the energy performance of buildings.” As the front line for delivering this work, many cities in Europe will be asking themselves, ‘but how?’
It is clear that this is just not possible without a close collaboration between cities to scale up and strengthen existing efforts, and, as part of our Twinning Learning Programme at NetZeroCities, Cologne (Germany) and Soria (Spain) have been putting this to the test.
These cities embarked last year in an exchange with URBANEW, a consortium of seven Spanish ‘Pilot Cities’ (Barcelona, Madrid, Sevilla, Valencia, Valladolid, Vitoria Gasteiz and Zaragoza) working towards urban regeneration.
At the beginning of this journey, facilitated by Eurocities, both Cologne and Soria as ’Twin Cities’ have designed a clear course of learning, aiming to accelerate the energy refurbishment of privately–owned households to achieve their climate neutrality goals in less than a decade. Representatives from both city councils and local partners like Cesefor, a foundation working on integrating new bio-economy and circular economy strategies in the city of Soria, identified good practices across the pilot cities and key stakeholders for their potential replication.
The first in-person meeting took place in March 2024 in the city of Vitoria-Gasteiz, who coordinate and lead the pilot, with the support of SustainableStartup&Co given the governance challenges of working with multiple and diverse cities. The host presented the Opengela model, which fosters an integrated approach for cities in the Basque country to support citizens to improve the energy efficiency of their homes, offering legal and technical advice. Thanks to the financial support from regional and local entities, the city council is transforming streets and making apartments not only more energy efficient, but more accessible and beautiful, including in less well-off neighbourhoods.

© Koelnmesse / Hanne Engwald
And with the digitalisation of existing public data, the municipality can assess the energy reduction potential of every single building in Vitoria-Gasteiz . This helps bridging the information gap between the city council, residents, and other interested parties such as the private sector.

© Koelnmesse / Hanne Engwald
In the past years, Barcelona has developed an impressive network of these ‘proximity offices’ through which they are paying special attention to refurbishments in social housing and vulnerable neighbourhoods, presented at the March workshop by representatives from the Municipal Institute of Urbanism of Barcelona and BIT Habitat Foundation As part of URBANEW, they are developing a catalogue of technical solutions and are exploring a financial model to do what they do faster and at scale. And Fundacio Clima i Energia from Valencia presented its plans to completely refurbish a publicly–owned building and provided more information about their model. They now have three energy offices in the city where information is provided, as well as training to increase energy efficiency and save money on energy bills.
Since March, twin cities have been exploring the different models of proximity (or energy) offices (also referred to as one-stop-shops) in Vitoria and Valencia and blending their best practices. For now, both cities have the political mandate to identify how to create these offices in an economically viable way and presented a draft replicability assessment during the second site-visit to the city of Cologne in September 2024.
In this meeting with representatives from Barcelona and Ensanche 21 (responsible for developing and implementing municipal policy on the rehabilitation of buildings in Vitoria Gasteiz), Cologne had the opportunity to showcase their climate ambition through the ´0 future 2035´ climate action campaign and platform, and highlighted its recently–inaugurated largest photovoltaic plant (with up 2.000 kWp of output) at Cologne Fair next to the city council premises.
It is clear that both Cologne and Soria have advanced a lot in the Twinning Learning Programme and are making the most of this peer-to-peer exchange, which will conclude in May 2025 after the third and last in-person workshop in Valencia.
In the coming nine months, both Twin Cities will finalise the replicability assessment and a replication plan to implement a model to fit their unique needs and realities. In the meantime, we have learned about each other’s cultures, and shared everyday struggles. This collaboration has above all been a delightful exchange amongst committed architects, civil servants, researchers, politicians, innovation and project managers, and facilitators, who together well represent the collaborative potential of the NetZeroCities Twinning Learning Programme.

© Koelnmesse / Hanne Engwald