Soil power lights Japan lab from 1,500 boxes

A test lab in Hitachi-ota, Japan, is lit by electricity collected from 1,500 wooden boxes of soil and compost, part of designer Satoshi Nakagawa's effort to show how very small currents could power low-energy devices.

Nakagawa, chief executive of Tripod Design, calls the method micropower collection. He said it uses electrodes made from materials such as zinc and copper inserted into substances containing moisture or ions to collect small but steady electrical currents.

A nearby installation called “Lu-An” has about 2,000 plastic cylinders of soil and compost and provides 100 watts of output, enough to power a rice cooker and other appliances, according to Nakagawa.

Nakagawa said the technology could be used in places without power, including after natural disasters, and for off-grid devices such as sensors to detect pest damage, overflowing rivers, landslides or burglar alarms. He said that once installed, the system produces no carbon dioxide and is not dependent on weather.

Masayuki Nakao, an engineering professor emeritus at the University of Tokyo, said the output is much lower than regular batteries or car batteries. But he said Nakagawa's light-based works can be aesthetically powerful and thought-provoking.

Nakagawa said engineers need to design products suited to micropower rather than judge it by the standards of larger power sources.