Engineers from the University of Trento in Italy are working on a system that captures the heat energy created by braking to charge the electronics on your bike.
A paper on the technology outlines a method by which energy is captured from braking and sunlight to run electronic components, including electronic gears, dropper posts, power meters and data telemetry equipment.
F1 cars and electric vehicles can use regenerative braking to capture kinetic energy as the vehicle slows down. Such a system could, theoretically, be possible for bicycles, too.
Thermal and solar energy harnessed
The paper identifies that “low-power, wireless actuators” are becoming increasingly common on bike components such as dropper posts, derailleurs, and even suspension forks and shocks.
This creates a need for batteries to power the tech. The paper investigates whether “innovative energy harvesting and management solutions that do not compromise rider experience” could reduce or eliminate reliance on batteries.
It examines two sources of energy; thermal energy generated by the brakes and solar energy. PhD student Maria Doglioni, one of the paper’s authors, explains the focus was to generate enough electricity to run actuators on electrical components, not generate enough current to charge large batteries such as those used on electric bikes.
This concept for energy harvesting is quite different from the regenerative braking systems used in electric cars. “We use wasted heat from friction when we push the brakes, whereas [electric] cars use reverse-running motors as generators,” says Doglioni.
Thermal energy captures the heat generated as your brakes convert kinetic energy from slowing you and the bike into heat energy. Instead of that heat energy dissipating into the atmosphere, thermal capture could harness it and channel it into a modern bike’s electronic system.
The system described in the paper captures energy from sunlight alongside thermal energy. The solar energy is captured using photovoltaic panels, changing the sun's radiation into electrical current, which can then be combined with the energy from the braking system and fed into electrical components.
How does it work?
The system uses an aluminium plate. This contacts the disc brake pads to transfer the heat energy to the thermal generator.
The thermal generator is attached to a 3D-printed mount. This bolts onto the post-mount disc brake caliper bolts and sits above the brake pads. The thermal generator transforms the heat energy into electrical energy, which can then be passed through wires to be used elsewhere on the bike.
It looks as though the system might be adaptable between different bicycle brakes without the need for spending big on bespoke calipers or unwieldy hardware.
Because it relies on thermal energy, this technology is also friction-free. This offers an advantage over dynamo setups, which introduce drag to your bike.
Elsewhere, the system utilises photovoltaic panels to capture solar energy. This is used in tandem with the thermal energy capture, to investigate whether, when combined, these two systems could create enough power to run electronic components, removing the need for batteries entirely.
The paper also states a possible use for the energy generated could be for running telemetry used on mountain bikes when descending. An example would be Mondraker’s MIND system, which collects suspension data that the rider can access via the myMondraker app.
Giuseppe Pasquini, another of the paper’s authors, explains a different approach was taken compared to the MIND system, which powers its own GPS (Global Positioning System). Instead, Pasquini says the research team used a custom app that employs a smartphone’s GPS for real-time data collection, saving harvested energy for the onboard sensors.
What does the future hold?
“To effectively power components like shifters and telemetry, we are advancing beyond standard technologies by implementing both lower power consumption and higher energy production,” says Pasquini.
Even in its prototype form, the product looks very minimal. It could bode well for a finished product if this pre-production version is already small and neatly packaged.
