Power plants light bus stop

Just the ticket: bus stop harvests plant power to fuel 24-hour light

Displayed at the Cambridge University Botanic Garden, the Plant 2 Power Hub is a simple wooden structure, designed by architect MCMM, supporting specially-adapted vertical green walled units and a mixture of regular and semi-transparent solar panels.

The structure aims to provide a 24-hour source of renewable energy, using solar panels during the day and at night harvesting electrons naturally produced by plants through photosynthesis and metabolic activity, and converting them into electrical current. Although the project is a live experiment, the researchers claim it could pave the way for simple and affordable power generation in developing countries.

Professor Christopher Howe and Dr Paolo Bombelli, from the Department of Biochemistry, developed the Plant 2 Power Hub. They previously created a device able to power a radio using the current generated by moss.

Opaque thin-film solar panels developed by Polysolar turn light into electricity on the hub, using mostly blue and green solar radiation.

Panels allow the red end of the spectrum, which is needed for photosynthesis, to pass through and reach the plants growing behind, while preventing the scorching effect of UV light.

Hamish Watson, chief executive of Polysolar, told RIBA Journal: ‘The semi-transparent panels do not absorb the full spectrum and are around 10%  less efficient than conventional PV. However, the team is trying to determine now how much energy can be generated from the plants and whether that can make up the deficit. We are also looking at factors such as how much light can be produced at different times of year, whether it needs to be supplemented with LED lighting, and the detrimental impact on plants of getting too much sunlight.’

The solar panels are based on those Polysolar installs into greenhouses, producing electrical energy to power irrigation pumps or artificial lighting.