EPFL students envision a more energy-efficient campus

With its carbon neutral strategy, zero-waste dining effort, and public transport and soft mobility plans, EPFL’s campus is already ahead of the curve when it comes to sustainability. But bachelor students Vassiliy Cheremetiev, Alain Schöbi, Alex Zanetta, Tim Flückiger, and Elisa Küenzi wanted to look for ways that the campus could become more self-sufficient. Despite being the second-largest consumer of energy in the canton of Vaud, EPFL only produces 3% of its own energy, via its solar park.

To see if this percentage could be boosted, the five students decided to examine the pros and cons of three more democratized approaches to energy production. The research was part of their group semester project for the Global Issues course on energy, which is part of CDH’s Social and Human Sciences (SHS) program.

Project supervisor Janet Su, a PhD student in the University of Lausanne Faculty of Business and Economics, said this work is particularly impressive given that the students did all their joint research and calculations, plus a poster presentation, entirely online.

"The students put a lot of hard work into their project; their ideas were well thought out and well researched. I am proud of the team, and hope to see some of their initiatives implemented on the EPFL campus one day!"

Windows, working out, and walking

First, the students examined the possibility of supplementing the solar energy already produced on campus with photovoltaic windows. They found that replacing all the south-facing windows at EPFL (a total surface area of 5,500 square meters) with photovoltaic panes could cover 2.1% of EPFL’s total energy consumption each year, resulting in potential cost savings of CHF 320,000.

“As their lifetime is very long, and their upkeep costs are not much more than those of standard windows, the installation of photovoltaic windows is definitely interesting from an economic perspective,” the students concluded.

Next, the students turned to two human-powered sources of energy: cycling and walking. They calculated that energy generated by the roughly 80 daily users of the stationary bikes at the campus sports center is equivalent to 13 kWh on a typical day during the semester. If the bikes were hooked up to generators, they could produce enough energy to power one five-room house, or to charge a smartphone 850 times. This could become cost-effective for EPFL, they found, if the bike-generator combos could be limited to a cost of CHF 200.

Finally, the students studied the potential of the piezoelectric effect, which describes the generation of electricity via the subjection of certain materials to mechanical stress. They calculated that a foot striking the ground generates about three joules of energy – a small amount, but perhaps not so small once it is multiplied by the thousands of daily footsteps on EPFL’s Méridienne. The students reasoned that if 46,000 piezoelectric flagstones were laid down on the iconic walkway, the daily foot traffic could generate up to 3.5 kWh – enough to charge a smartphone 270 times. Unfortunately, in this case, the students found that the cost of installing such stones would likely outweigh the energy cost savings.

Overall, the team concluded that solar windows and bikes could be very interesting and cost-effective energy options for EPFL’s campus.

“The option that we would most like to see implemented is that of the generator-bikes. This would involve students in energy production, and its implementation would be both innovative and within our reach. Solar windows seem promising, but it would be more interesting to install them in a few years, in view of the research and progress that is being made,” the students said.

They added that other benefits could go beyond costs savings: “Although the total energy production of these installations remains very small compared to EPFL’s large consumption, the presence of these unconventional approaches recalls the importance of energy in our society, and could motivate the reinvention of green energy.”