Portugal's vast network of railway corridors—stretching across 2,527 kilometres of active track—may eventually generate clean electricity without consuming agricultural land. A Swiss startup called Sun-Ways has successfully tested removable solar panels positioned directly between railway ties, a concept that could allow European nations to explore renewable capacity while avoiding the land-use conflicts that plague traditional solar parks.
The Current Pilot Project
The demonstration project currently running in Switzerland provides the only operational data available. Sun-Ways has deployed 48 solar panels across a 100-metre section of track in Neuchâtel canton. These panels have been generating electricity without interruption, producing approximately 16,000 kilowatt-hours annually. The system is designed to be removable for maintenance, with a specialized machine capable of lifting entire sections horizontally to clear the corridor when access is needed.
The panels remain operational while trains pass overhead. The engineering allows for uninterrupted train movement, and initial results show that air displacement from passing locomotives actually helps dislodge accumulated dirt—providing a passive self-cleaning effect. No service interruptions have been recorded during the pilot phase.
Why This Concept Interests Portugal
For Portugal specifically, the theoretical potential is noteworthy: if solar panels were eventually deployed across Portugal's electrified rail network, such technology could contribute meaningfully to renewable energy generation without competing with agriculture or requiring additional land.
Key advantages of railway-based solar:
• Land preservation: In-track installations would occupy zero agricultural territory, valuable for countries balancing energy production with food security.
• Existing infrastructure: Portugal's state rail operator, Infraestruturas de Portugal (IP), already operates and maintains this corridor network, potentially simplifying deployment logistics compared to new solar developments.
• Grid integration: Most existing electrified lines connect to traction substations within accessible distances, meaning power could theoretically feed directly into railway systems.
How the Technology Works
Each modular panel sits in the ballast layer—the gravel bed between sleepers—capturing sunlight without obstructing train movement. Sun-Ways designed the mounting system to withstand vibration and the challenging railway environment. When maintenance is required, specialized equipment can remove sections without lengthy disruption.
Critical Open Questions
Significant uncertainties remain before this technology could be deployed commercially:
• Long-term durability: The pilot runs through 2028 specifically to test how panels respond to constant vibration, temperature cycling, metal particles from braking systems, and winter conditions over an extended period. Crystalline silicon can develop micro-cracks under constant vibration—a concern that requires years of operational data to properly assess.
• Economic viability: Sun-Ways has not publicly disclosed installation costs, maintenance expenses, or projected revenue figures. Without confirmed pricing and performance guarantees, operators cannot evaluate whether the technology makes financial sense compared to alternatives.
• Regulatory pathways: European rail operators have not yet established clear permitting frameworks for in-track solar installations. Each country would need to develop safety protocols, electromagnetic interference standards, and maintenance procedures.
• Operational risks: Railway operators guard their infrastructure carefully. Concerns about vandalism, theft of remote-mounted equipment, panel failures that could lodge between rails, and system complexity all require resolution before commercial deployment.
European Interest and Timeline
France's SNCF, Germany's Deutsche Bahn, and Italy's RFI have expressed interest in monitoring the Swiss pilot results. The concept aligns with European Union renewable energy mandates, which require member states to derive substantial portions of final energy consumption from renewable sources by 2030.
Sun-Ways is targeting development of commercial-grade installation equipment by late 2027, contingent on pilot durability results. Any European deployment—including potential Portuguese adoption—would likely follow successful completion and analysis of these initial trials.
The Broader Context: Infrastructure Reuse in Energy Transitions
Europe's renewable energy transition faces significant land-use constraints. Traditional solar parks consume substantial acreage per megawatt. Europe's railway network represents approximately 250,000 kilometres of existing linear infrastructure, much of it already sun-exposed and engineered for durability. Railway-based solar represents a theoretical opportunity to harness existing infrastructure for renewable generation without agricultural competition.
However, this remains conceptual until the Swiss pilot conclusively demonstrates technical viability, economic sustainability, and operational safety over multiple years.
What Could Happen Next
If the Swiss pilot successfully resolves durability questions by 2028, European rail operators may begin exploring demonstration projects in their own countries. Portugal could potentially be a candidate for such a pilot, given its renewable energy targets and existing rail infrastructure. However, any Portuguese involvement would depend on:
• Successful completion of the current Swiss trials
• Positive results on panel longevity and performance degradation
• Clear cost structures and revenue projections from Sun-Ways
• Regulatory frameworks established by Portugal's Ministry of Environment and Climate Action
• Demonstrated safety protocols acceptable to European rail standards
At present, the technology remains in active testing. Speculation about deployment timelines, specific cost figures, or Portuguese government commitments would be premature. The focus should remain on what the Swiss pilot will reveal by 2028—answers that will determine whether this concept advances from theory to operational reality across Europe.
