With IoT devices becoming smaller, more widespread, and increasingly expected to operate for years without intervention, manufacturers are racing to develop ultra compact, low- or no-battery power solutions for sensors.
One company pursuing this shift is Ligna Energy, the Swedish supercapacitor manufacturer, which at embedded world 2026 showcased Gwen, a battery-free indoor climate sensor designed to harvest ambient indoor light and support maintenance-free temperature and humidity tracking across building environments.
At the core of Gwen is a supercapacitor, a type of energy storage device that sits between a traditional capacitor and a battery. Capacitors store and release energy very quickly but hold relatively little of it, while batteries store far more energy but release it slowly and degrade over time.
Supercapacitors bridge this gap by enabling rapid charging and discharging like a capacitor, but with significantly higher energy storage, making them ideal for short, high-power bursts in IoT systems such as wireless transmissions and sensor updates.
Historically, they have been used for backup power, memory protection, and peak power support in electronics, but are now increasingly being considered as part of energy harvesting systems for connected devices.
“Battery-free can be a better product experience,” said John Söderström, Marketing Director at Ligna Energy.“When you remove routine battery swaps, you unlock simpler operations and new possibilities for where sensors can live.”
Söderström added that Gwen is intended as a reference design rather than a finished product. “We are not trying to build a one-size-fits-all sensor,” he said. “The goal is to show how ultra thin energy storage can enable entirely new form factors for OEMs.”
The system stores harvested energy in Ligna Energy’s S-Power supercapacitor and transmits data via Bluetooth Low Energy, removing the need for battery replacement cycles and reducing long-term electronic waste.
This article originally appeared in the May 2026 magazine issue of IoT Insider.
