BWI-C40 Learning Tour | Madrid | 24 March 2025
Location: ACCIONA Campus & Santiago Bernabéu Metro Line Construction Site

The shift to a low-carbon economy in construction must be systemic, not cosmetic. That was the clear takeaway from a joint learning tour organised by Building and Wood Workers’ International (BWI). UGT-FICA, and CCOO del Hábitat, and C40 Cities, hosted by ACCIONA, a global infrastructure leader with operations in over 40 countries and a longstanding Global Framework Agreement with BWI.

On 24 March 2025, participants from unions, cities and allied organisations toured Madrid’s ACCIONA Campus and the Santiago Bernabéu Metro Line construction site. The goal: to understand what clean construction, worker participation and digital innovation look like in practice — and how these elements can work together to ensure a just transition for workers in one of the world’s most emission-heavy sectors.

“We’re not just witnessing innovation. We’re seeing how worker voice is central to managing technological and green transitions in ways that are safe, inclusive, and fair.” Paola Cammilli, Global Campaigns Director, BWI

The Journey: From Data-Driven Safety to Decarbonised Sites

Stop One – ACCIONA’s OSH and environmental monitoring centre

The learning tour began at ACCIONA’s state-of-the-art Health and Safety Control Centre, which monitors over 600 construction projects across the globe. This centre integrates artificial intelligence and digital tools to track working and environmental conditions in real time. By drawing on data from on-site audits, inspections, advanced weather forecasting, air quality indicators, and thermal exposure metrics, the system is designed to anticipate risks before they escalate into hazards.

By combining predictive analytics with environmental monitoring, the platform shifts occupational safety from reactive responses to proactive prevention. It enables tailored corrective actions to safeguard worker health, reduce environmental impacts, and enhance project performance. However, as ACCIONA’s team underlined, embedding such technologies is not purely a technical exercise, it is also a cultural transition. Ensuring that workers at all levels are trained, involved, and equipped to operate and engage with these systems is essential to their success and sustainability.

Rather than replacing worker judgment, ACCIONA emphasises how digitalisation supports worker well-being. Importantly, AI tools are used to identify patterns of non-compliance but are carefully anonymised to protect worker privacy and avoid surveillance. Instead, the focus is on identifying risk, initiating preventive actions, and taking real-time corrective measures.

“Investing in innovation must mean investing in workers. What we saw today is a model that combines safety, trust, and technology. Digitalisation, when guided by ethical use and strong union dialogue, can significantly improve site safety and environmental outcomes.” Sergio López Rivera, Construction Secretary at CCOO del Hábitat


Stop Two – A systemic approach to sustainable construction at ACCIONA Madrid

At the Santiago Bernabéu Metro Line construction site management office, participants were welcomed by the ACCIONA team for a detailed on-site briefing and discussion. This session illustrated how a climate transition in construction is not just about replacing materials or introducing new technologies, it is a transformation in how we build. From reducing embodied carbon through cleaner materials to optimising energy use and minimising waste, the transition to low-emission construction fundamentally reshapes work processes.

Crucially, participants convened that this change cannot succeed without the expertise, full engagement, and participation of workers. As ACCIONA’s team and union representatives made clear, workers are not just implementers of the green transition, they are its architects and should have full ownership of the change. Their on-the-ground experience is essential for designing safer, smarter, and more sustainable processes. That’s why training, skills development, and inclusive social dialogue are at the heart of ACCIONA’s sustainability strategy.

Participants learned that shifting to low-carbon construction also brings important safety co-benefits: automation of high-risk tasks can reduce accidents, exposure to chemicals can be mitigated through new techniques and materials, and improved site management supported by digital tools can enhance worker health and protection.

“This is what makes the transition not only green, but just. It’s a transformation that values the workforce, reduces emissions, and makes construction sites safer, healthier, and more future-ready.” Stephen Craig, UNITE the Union

In its briefing, ACCIONA presented its decarbonisation pathway that targets to reduce emissions by 60%* by 2030, and 90% by 2040. The company plans to address increased turnover by improving efficiencies through reducing manufacturing times and construction processes, decreasing amounts of materials used, improving the features of construction materials, minimising defects during construction processes, early problems detection and corrective maintenance, increasing productivity by optimising performance of construction sites, improving collaboration, using real and on-time data in decision-making, and improving safety by reducing accidents on sites and automising construction and O&M processes. So far, these strategies have been received well by workers and their representatives, showing that embedding workers’ safety in decarbonisation pathway can bridge social anxieties surrounding a just transition.

Stop Three – A Just Transition at the Santiago Bernabéu Metro Line construction site


Next, the group visited ACCIONA’s worksite at the Bernabeu metro station. There, digital safety protocols, low-carbon materials, and worker-first solutions are reshaping one of Madrid’s busiest transit hubs:

• Low-carbon cement and sustainable timber are being used to cut emissions;
• Electrified machinery is lowering both carbon output and accident risks.
• Worker heat stress prevention protocols, including smart wearables like temperature bracelets, and
• heat-adjusted schedules help workers avoid dangerous heat.

“When we talk about adaptation, it’s not theoretical, it’s life-saving. Last summer, temperature bracelets and real-time alerts helped prevent heat stress during the most dangerous hours.” Àngel Barroso, a site foreman

What Made the Difference? Dialogue and Innovation

At the heart of this transformation is social dialogue and thriving industrial relations between the multinational company and unions, both in Spain and globally. ACCIONA’s partnership with UGT-FICA and CCOO del Hábitat shows how early and meaningful trade union involvement can enhance workplace health, safety, and environmental sustainability.


“A just transition must be shaped from the ground up. That means protecting workers and listening to their concerns, not after innovation, but as part of it.” Sergio Estella, UGT-FICA


From City to Global Action: Lessons for a Just Transition

This learning tour demonstrated that digitalisation, climate adaptation, and industrial transformation are not just technical or policy questions. They are workplace issues, with consequences for safety, job quality, and dignity.

“Cities are not just where climate emissions happen, they are where climate solutions are tested. What we saw in Madrid proves that clean construction for public purpose, when rooted in social dialogue between companies and unions, and a clear regulatory framework by the city, can be a powerful tool for sustainable urban transformation.” Cecile Faraud, C40 Cities

Key takeaways include:

• Clean construction reduces emissions and improves health

The shift to low-emission materials and electric equipment isn’t just good for the environment, it’s good for workers too, but it requires adapting processes and standards on site. Reducing carbon through materials, electrification and modular methods also reduces exposure to dust, chemicals, and heat. This makes environmental goals immediately relevant for frontline workers.

• Digital tools must enhance, not replace, worker knowledge


The use of AI and predictive data is most effective when workers are informed, consulted, and protected. Digital tools and AI, when ethically implemented with worker involvement through consultations on risk identification, corrective actions, and training needs, can reduce on-site risks and predict climate-related hazards. In Madrid, anonymised data, training and joint protocols show how digital innovation does not need to erode worker rights, but can strengthen OSH frameworks when implemented through dialogue.

• OSH must be adapted to a warmer world


The visit underscored the need for national legislation and collective agreements that protect outdoor workers from extreme temperatures. Madrid’s example shows how worker safety in extreme temperatures can be managed with smart tools and strong policies.

• Industrial relations are not optional – they’re essential


All of these advances were possible because of mature industrial relations. The partnership between ACCIONA and UGT-FICA, CCOO del Hábitat and BWI, is rooted in freedom of association and collective bargaining, and anchored in social dialogue and joint actions. This culture of negotiation enabled workers’ engagement, smoother transitions and higher standards.

What this means for the future

The Madrid visit was part of a broader series of learning tours supported by the Laudes Foundation, showcasing what real-world progress looks like in key European cities, when workers’ voices are factored in the transition to a net-zero economy.

The visit reinforced a simple truth: you can’t have clean construction without decent work. And you can’t talk about clean construction without talking about:

• Safe working conditions,
• Worker voice, representation and training,
• Public procurement with labour standards,
• Innovation grounded in ethics.

This is what a just transition looks like in practice.