By Amrutha Rao, Cara Wang, and Colin Chu

Powering a Sustainable Future

We live in a world where climate change remains a pressing, unresolved issue. Therefore, the Environmental Engineering Club at Nueva believes that we must proactively innovate, build, and create solutions to mitigate and spread awareness about the climate crisis. In recent years, the development of sustainable energy sources has gained increasing attention due to the harmful effects of non-renewable energy, such as fossil fuels, on the environment. Additionally, the production and disposal of non-rechargeable batteries release toxic chemicals into the air, contributing heavily to global warming (RSC). This is why, through our love of engineering and finding solutions to climate change, we — Amrutha, Cara, and Colin — created RainCharge: a device that generates electricity from rainfall to recharge batteries. We hope that RainCharge will help reduce the negative effects of climate change and promote climate resiliency within our community—and beyond. 

How It Works

RainCharge utilizes piezoelectric disks to generate electricity from rainfall. Piezoelectric materials can produce electricity upon the application of stress. In RainCharge, the disks, when subjected to pressure from falling raindrops, produce an electric charge. By harnessing this natural force, RainCharge taps into a clean and renewable energy source, reducing our reliance on traditional power grids.

RainCharge consists of a circuit integrated into a 3D-printed base. Piezoelectric disks are arranged in parallel to maximize energy conversion. These disks are connected to a circuit board equipped with diodes, a capacitor, resistors, and a rechargeable AAA battery. The device is designed to charge 1-2 rechargeable batteries simultaneously, and its portability and user-friendly design make it accessible to users of all ages. RainCharge can be attached to the top of a roof, car, and more. 

Based on experimental results and calculations, RainCharge generates 2 volts for 30 seconds, translating to approximately 2.944 milliwatt hours. In just 2.12 hours of rain, RainCharge produced enough energy to fully charge a AAA lithium battery, which typically requires 750 milliwatt hours.

The Significance of Our Device

The potential of RainCharge goes beyond its eco-friendly energy generation; the device also plays a crucial role in addressing battery waste. The batteries charged by RainCharge can power a wide range of devices, from household appliances like remote controls and flashlights to essential equipment in underserved communities, such as cooking appliances and medical devices. RainCharge aims to ensure that every household in our community can incorporate this innovative solution into their daily lives, fostering climate resiliency and sustainability.

So far, RainCharge has received funding from Acterra (via a partnership with EarthForce) and the Joey Kovacevich Social Innovation Fellowship (The Nueva School), and was named as a finalist in the international Genius Olympiad science competition (which we were unable to attend, due to a conflict) and the Paradigm Challenge.

Looking forward, RainCharge has the potential to address energy poverty, greenhouse gas emissions, and toxic battery waste. Our vision is that one day, RainCharge will be widespread and globally accessible.

This post was authored by Amrutha Rao (Grade 12), Cara Wang (Grade 11), and Colin Chu (Grade 10), three high school students at The Nueva School in San Mateo. Our team created RainCharge through Nueva’s Environmental Engineering club, of which Amrutha Rao is the founder and president, Cara Wang is the vice president, and Colin Chu is the head analyst. All three students took part in various aspects of the engineering and design process for the device.