Soil battery uses bacteria to power field sensors ^{CEFR B2}

A UK university spin‑out has developed Bactery, a low‑cost eco‑battery that uses soil microorganisms to harvest and store electricity. The device is intended to power sensors and Internet of Things devices in agricultural fields where conventional power delivery is difficult or costly. Always‑on field sensors can provide farmers with near real‑time information on soil health, crop development and local environmental conditions.

The University of Bath team first proved the concept in 2019 when they built and tested a soil‑powered water disinfection prototype in Icapuí, a fishing village in semi‑arid north‑east Brazil. The pilot showed it was possible to use soil electricity to power an electrochemical water‑treatment reactor where rainwater is the main drinking source and grid power is scarce.

The company says it has developed ways to scale and sustain electricity generation and that the eco‑battery avoids obstructive cabling, single‑use chemical batteries and weather‑dependent solar panels. The device works by exploiting soil microorganisms called electrigens, which produce electrons when they consume organic matter. A key technical issue is that the electrode environment must be anaerobic to prevent electrons binding to oxygen; the system therefore targets conditions where plant roots are submerged in water to create an oxygen‑free zone and aid electron transport. CEO Jakub Dziegielowski says installations can target suitable natural sites or be semi‑engineered to reduce dependence on moisture.

• Anticipated cost is around £25 per unit (US$32).
• The company describes the product as "install and forget" with a lifespan of over 25 years.
• It plans prototype refinement next year and aims for small‑scale production in 2026 while seeking collaborators and investors.