Trains move, air moves. It's basic physics, but until now no one had built an energy business model on it. The University of Manchester He tried: vertical wind turbines installed in railway tunnels that exploit the piston effect generated by trains. The artificial wind generated by the passing trains turns the blades, which produce energy. Energy that is needed right there: lighting, signage, emergency systems. All without adding a single gram of CO2. The project has already passed feasibility studies and is now preparing for testing on real infrastructure. If it works, well, that's a great thing.
The piston effect of the tunnels becomes a resource
A convoy entering a tunnel pushes a considerable mass of air in front of it. It is a phenomenon known for decades, studied above all for the design of emergency ventilation systems. Air compression generates flows that can reach significant power, especially in longer and busier tunnels. The team Department of Mechanical and Aerospace Engineering of the English university, led by Dr. Amir Keshmiri, developed vertical axis wind turbines (VAWT) specifically designed for these intermittent and multidirectional flows.
The pilot project starts from the line Transpennine Route UpgradeIn partnership with Q-Sustain Limited, an engineering consultancy firm based in Manchester.
The toolkit that calculates economic yield
The heart of the project is not just the turbines. It is VerXis Wind, a techno-economic analysis software developed by the team. Enter the tunnel's geometry, train schedules, and characteristics. In just a few minutes, the system returns banking-level financial indicators: how much it produces, how much it costs, and when it will pay for itself. Keshmiri explains it clearly:
“We are bridging the gap between academic innovation and real-world implementation, making piston-effect wind turbines not only technically feasible, but genuinely investable.”
Azhar Quaiyoom, Director of Q-Sustainhe adds:
"VerXis allows us to rapidly test and scale turbine designs for each specific tunnel environment. It enables data-driven decisions to implement sustainable solutions in rail infrastructure, aligned with the UK's net-zero targets, and calculates the return on investment for our customers."
Why vertical turbines work better
Vertical axis turbines have distinct advantages in this context. They do not have to face the wind because they capture flows from any direction. Trains run both ways, air moves back and forth, VAWTs still work. One 2020 study published on Electronics demonstrated that in open railway configurations (not in tunnels, but along the tracks) a system of vertical turbines can generate up to 32,3 MWh per year considering the passage of trains, compared to the 30,6 MWh produced by natural wind alone.
In tunnels, where the piston effect is more concentrated and predictable, efficiency could increase. The turbines operate at low cut-in speeds, activating even with modest flows. And they require less maintenance than horizontal turbines, which would be difficult to install and operate in confined spaces.
Not just railway tunnels
The model could be extended. Road tunnels, subways, even industrial ventilation ducts. Every time there's a regular, wasted flow of air, there's an opportunity. A recent study published in Scientific Reports analyzed how micro wind turbines could capture the air movement generated by large HVAC fans in data centers. In a Colombian facility with two 24/7 chillers, a six-turbine system generated 513,82 MWh annually, enough to cover the fans' power consumption with a surplus of 131,2 MWh.
The next phase of the Manchester project involves testing in real tunnels and further developing the VerXis toolkit. The aim is to influence future rail energy standards, not only in the UK but throughout Europe. If the model proves scalable, we could see turbines installed in thousands of kilometers of tunnels within the next decade.
The basic idea is simple: if something moves and displaces air, that's energy. So far, we've let it dissipate. Maybe it's time to put it to work.
