The Municipality of Braga, a medium-sized city in the north of Portugal, has committed to achieving carbon neutrality by 2050 under its Sustainable Energy and Climate Action Plan (SECAP), now operationalised through the Municipal Climate Action Plan (PMAC). To achieve this goal, Braga is implementing a wide range of measures, seeking to maximise co-benefits through integrated approaches, including through the promotion of decentralised renewable energy paired with nature-based solutions in urban planning.
The opportunity to combine PV potential assessment with bio-roof feasibility analysis came through the European City Facility (EUCF) in 2022, which supported Braga's proposal with a €60,000 grant. This enabled the city to commission a technical study and develop a publicly accessible digital platform, providing citizens and companies with the information needed to make informed decisions about solar energy investments.
The project was developed in partnership with local business associations (Associação Empresarial de Braga, Associação Empresarial do Minho, CIM-Cávado), the regional energy agency (Agência de Energia do Cávado), and the city’s economic development agency (InvestBraga), ensuring broad community engagement and effective dissemination of results.
Together these entities worked toward the following objectives:
- Assess the photovoltaic potential of buildings across the municipality
- Identify locations with the highest solar energy production capacity
- Analyse the potential for implementing green roofs (bio-roofs) combined with photovoltaic systems
- Promote carbon emission reductions and climate change mitigation
- Encourage the adoption of sustainable energy solutions by citizens and businesses.
From technical study to public digital platform
The municipality led the development of a detailed technical study assessing PV potential across approximately 30 km² of urban, industrial and economic activity areas defined in the Braga Municipal Master Plan. Using drone-based photogrammetry and GIS tools, more than 50,000 buildings were analysed, with building-level data collected on solar radiation, roof slope and bio-roof feasibility.
Based on this analysis, a publicly accessible digital platform was launched in early 2023. The platform is built on ArcGIS MapSeries and works in two ways. Users can locate any analysed building on an interactive map to view its building-level data making it very specific rather than a generic regional tool. Users can also run the integrated simulator, either with standard consumption values or their own electricity bill figures, to generate a personalised calculation of installation cost, expected annual savings and payback period. This allows users to simulate investment costs, expected savings, and payback periods, using either standard data or their own energy consumption figures.
This platform responds to both climate and socio-economic challenges by enabling citizens and businesses to better understand and invest in renewable energy solutions. The municipality ensured that the platform is freely accessible and designed for a wide audience, including households, SMEs, and larger companies.
Braga actively promotes the tool through communication campaigns, social media (Facebook, Instagram, and YouTube), public events, billboards, collaborations with business associations, presentation sessions for the public and local businesses, and promotion on local and national press.
Integrating roof panels with bio-roofs
A distinguishing feature of this project is the integration of bio-roofs alongside PV systems. A bio-roof consists of a vegetation layer planted on a waterproofing system installed on top a flat or gently sloped roof. The cooling effect provided by vegetation improves the performance of photovoltaic panels, particularly during high-temperature periods, while simultaneously delivering broader environmental and urban benefits such as improved building insulation, reduced urban heat island effects, enhanced biodiversity, and improved urban aesthetics.
This combination of climate mitigation, climate adaptation, and nature-based solutions represents a key differentiating factor compared to conventional solar mapping tools.
Putting the social dimension at the heart of the project
To support citizens in acting on the platform’s outputs, Braga joined the national network of Espaço Energia (Energy Space) to establish an advisory centre, where residents can access free technical advice on self-consumption, electric mobility and sustainable tariffs. This walk-in service complements the digital tool directly; where the platform identifies potential and runs simulations, the Espaço Energia supports citizens in navigating next steps, building energy literacy and confidence to invest.
Financial constraints, however, remain a critical challenge, particularly for vulnerable households. To address this, the municipality complements the platform with targeted financial support through the Municipal Energy Poverty Mitigation Programme, which provides 100% funded vouchers of up to €2,500 per household for a range of eligible interventions, including window replacement, thermal insulation, heat pumps, solar thermal systems and PV panel installation. Now in its fourth edition (2026), the scheme reinforces the social dimension of the energy transition, ensuring that lower-income households are not excluded and can move from interest to implementation.
Impacts and Outcomes
The project has delivered significant technical, social, and economic results. The study concluded that full deployment of PV systems across the assessed area could generate up to 160 GWh of renewable energy per year, reducing CO₂ emissions by approximately 35,524 tonnes annually, roughly 7.7% of Braga’s total emissions (458.4 kt CO₂ in 2022).
The platform empowers citizens and businesses with accessible, personalised data, enabling informed investment decisions and contributing to increased energy autonomy, all elements that are particularly relevant in the context of rising energy prices. The project has also strengthened collaboration between the municipality, business associations, and regional stakeholders.
The project has inspired wider discussions on renewable energy adoption and contributed to Braga’s recognition as an innovative and climate-active city. In 2023, the municipality received the DECO ‘Friend of the Consumer’ distinction in the Carbon Neutrality category.
Lessons learnt and next steps
Braga’s experience highlights the importance of combining data accessibility with practical support mechanisms. Providing clear, building-level information significantly increases users’ willingness and ability to invest, but information alone is not sufficient. Advisory services and financial incentives are essential to translate interest into concrete action.
The project demonstrates the value of integrating digitalisation, renewable energy, and nature-based solutions within a single framework, supported by strong stakeholder engagement. The platform’s user-friendly design, building-level data, and free public access reduce barriers and build trust, while partnerships with business associations and regional organisations ensure broad dissemination, particularly to SMEs. This approach is replicable and adaptable to other urban contexts.
Recent national investments in grid resilience and decentralised energy systems, accelerated following the 2025 Iberian blackout, have further highlighted the importance of local planning capacity and reinforced the value of tools such as Braga's Solar Map beyond individual investment decisions.Looking ahead, Braga plans to:
Looking ahead, Braga plans to expand and continuously update the platform with new building, energy and geospatial data. Beyond the data maintenance, there is a strategic push to bridge the gap between technical potential and financial reality by forging stronger connections with funding schemes and diverse financial instruments, thereby lowering the barriers to entry for investment.
This forward-looking approach also places a renewed emphasis on deepening engagement with small and medium-sized enterprises as well as industrial stakeholders, recognizing them as pivotal players in the city's energy transition. Furthermore, Braga aims to institutionalize sustainability by promoting bio-roofs not merely as an optional add-on, but as a standard component of municipal urban planning.
To ensure these ambitious goals translate into tangible results, the city plans to enhance its advisory services through Espaço Energia and the Municipal Energy Poverty Mitigation Programme to support citizens throughout the investment process. Lastly, Braga is now exploring future integration with local energy communities and smart energy planning initiatives.
Braga, Portugal
Covenant Signatory since 2013
Population: 281.000
Area covered: 183 km2
Key Figures
- 30 km² of urban areas and >50,000 buildings assessed in the solar mapping
- Up to 160 GWh/year estimated renewable energy potential
- ~35,524 tonnes/year estimated CO₂ reduction potential
Overall CO2 emissions reduction target:
- - 55% GHG emissions reduction by 2030
- Climate neutrality by 2050
Useful links:
Financing the project
- €60,000, funded through the European City Facility (EUCF) grant, covering the feasibility study, technical development and launch of the solar mapping platform.
- Maintenance and updates are supported through Braga Municipality’s climate and energy planning budgets.