These Glowing Green Batteries Are Alive, and They Never Run Out

There is a small transparent slab sitting in a Cambridge lab, filled with what looks like pond water, quietly powering a clock radio.

It has been doing that for six years. Nobody has changed a battery, because there is no battery. There is only algae, light, and a very old chemical trick.

The device is called a biocell. It comes from a collaboration between the University of Cambridge’s Department of Biochemistry and bio-designer Lucia Giron, who spent two and a half years turning lab research into objects you can hold and plug in.

The science is biophotovoltaics, which is basically a solar panel that happens to be alive. Inside the casing are cyanobacteria, the blue-green algae that invented oxygen production a couple of billion years ago. As they photosynthesise, they release a trickle of electrons. Capture those and you have current. Not much, but enough, and it never stops.

The target is obvious: the millions of tiny disposable batteries inside remote controls, smoke alarms, and sensors, each one mined out of the ground and eventually thrown back into it.

What we love is that the design refuses to hide the biology.

The case is transparent because the algae need light, and because we should get to watch them work. The electrode has a fine hairy structure so the organisms have somewhere to settle. A membrane lets gas move through while keeping the water in. The front plate carries a delicate leaf-vein pattern, which tells you what is happening inside without a single word. That plate comes off, and the whole thing comes apart for reuse or recycling.

The algae are never consumed or harmed. They just live, and generate, for as long as they live.

Giron and the team built two working demos: a disc powering a temperature sensor, and a rectangle wedged into a clock radio. Both are still bigger than the devices they run. A spin-out called e-Pho is working on that, and the cells will shrink.

Giron makes a good case for not shrinking them out of sight entirely. Most of our energy systems are designed to disappear into walls. With these, she says, “part of the opportunity is that they make energy production more visible.”

A green rectangle on a shelf, doing nothing you can see, quietly running the clock beside it. Six years and counting.

Story via Dezeen. Design by Lucia Giron with the University of Cambridge.