Piezoelectric Energy Harvesting

From January 1 to November 8, 2023, our school had accumulated approximately ₩190 million in electricity costs—already more than ₩10 million above the total from the previous year.

As an unaccredited alternative school, our school faced higher electricity rates than ordinary schools. But the problem was not only the price of electricity.

A survey conducted during an information class revealed repeated cases of electricity waste: lights left on in empty rooms and air conditioners or heaters operating when nobody was there.

I wanted to find a way not only to generate electricity, but also to make students more aware of where electricity comes from and why conserving it matters.

I became interested in energy harvesting: capturing small amounts of energy that would otherwise be unused, such as sunlight, heat, wind, or vibration, and converting it into electrical energy.

Piezoelectric materials offered one possible approach. When mechanical pressure or vibration is applied to a piezoelectric element, it can generate electrical energy.

After encountering examples of piezoelectric flooring used to generate power from footsteps, our team decided to explore whether a similar system could work within our school.

Our initial hypothesis was that a floor tile containing piezoelectric elements could generate electricity from students' footsteps and use that energy to improve the school environment.

We planned to connect the generated electricity to LED strips in a dark pathway on campus.

We also recognized that a small piezoelectric installation was unlikely to reduce the school's electricity bill significantly. The visible response of an LED therefore had a second purpose: to help students experience how much effort is required to generate even a small amount of electricity.

Our first survey suggested that the area in front of the cafeteria would be the best location because many students passed through it.

But collecting electricity in one location and transferring it to a distant dark area would make the system unnecessarily complicated. We reconsidered the plan.

During a second investigation at night, we evaluated both ambient brightness and distance. Based on those observations, we selected the pathway between the intersection and the Jomullak area as the final installation site.

We attached glow-in-the-dark markers and connected the prototypes to LED strips before installing them along the selected pathway.

Stepping on the tiles successfully generated electricity, and we confirmed that the electrical output could illuminate the LED strips.

In that sense, the core prototype worked: mechanical energy from a footstep could be converted into visible electrical output.

The outdoor installation quickly exposed weaknesses in the design. Our waterproofing was insufficient, and moisture and rain damaged the LED strip.

More importantly, the amount of electricity generated by the piezoelectric elements was extremely small.

The system could demonstrate electricity generation, but it could not continuously illuminate the dark pathway or meaningfully reduce the school's electricity costs.

Our original technological solution therefore failed to solve the larger problem that had motivated the project.

We began by asking whether students could produce useful electricity simply by walking across a floor tile.

By the end of the project, however, the tiny amount of electricity we generated had become the most important result.

If repeatedly stepping on a piezoelectric tile could barely save enough electricity to matter financially, then turning off an unnecessary light, heater, or air conditioner was far more meaningful.