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Article Green tech

Making sparks with plants


Words by Suzanna Knight

Illustrations by Melanie Corre

Photos by Sophie Wright

“Could you turn on the plant?” It sounds strange but it might become a common phrase in the near future. Instead of flicking on a light switch, your houseplants could provide you with enough energy to fuel your lamps or charge your cellphone. Or even function as sustainable energy sources in places where solar panels or wind turbines don’t work. It’s something Plant-e has been experimenting with since 2009. Revolving around water and plants, the technology they work with is science fiction come to life.

Seeing is believing

“If you go somewhere and say, ‘We generate electricity with living plants,’ the response is: ‘What? Really? I don’t know about that. That’s cute technology.’ Yeah, it’s cute but it’s real as well,” reflects Nanda Heshof-Schrama, Plant-e’s operational manager. Consisting of a small and seasoned team of experts, Plant-e was founded by Marjolein Helder and co-promoter David Stirk at Wageningen University, as a spin-off from the university’s sub-department of Environmental Technology. Focused on research and development, Plant-e aims to develop the technology in the lab, put it to the test, and introduce it to the rest of the world. And most importantly, to help people understand the exact process and scope of what the technology could be. To do this, the team has developed small DIY kits that allow people to build their own plant batteries, explaining the technology along the way. They also developed a square metre system made up of 50 x 50cm modules. One square meters can be used to light up LED lamps, and one hundred square meters would be enough to serve as a Wifi hotspot.“It’s decorative, just fun stuff, to see that it works and that it’s really possible to do this. Of course, these 50 x 50 modules aren’t going to be put on large stretches of land, so we are developing a tubular system that can be placed in any type of green wetland,” says Nanda.

How it works

In a nutshell, plants release organic matter as a waste product, which is broken down by bacteria.The latter releases electrons during this process. If you capture electrons in a wire, you can use them as electricity.“Plants grow from photosynthesis. They use the organic matter they produce in the process to grow, but part of the organic matter is also excreted into the soil via the roots. Around the roots, bacteria eat the organic matter, and some of these bacteria groups are able to release electrons in the process, as a waste product,” Nanda explains. Plant-e lets the plants grow in electrode materials, like carbon granules and combines that with a counter-electrode. In case of the DIY boxes the counter-electrode goes on top. The black wire from the bottom of the pot and the red wire from the carbon felt meet in the circuit board, and together they create electricity.

Photo via plant-e.com

Plants as solar panels

The technology being developed in the Plant-e lab could be used for many different purposes. Though not as powerful as a wind turbine or a solar panel, plants could be used in areas where the latter don’t work as well. “Our goal is to make electricity in wetlands – large-scale, multiple land-use areas like rice fields, where there are large problems with methane gasses. As bacteria decompose organic matter, methane gas is formed. If we provide our system to the bacteria they can use the electrode to donate the electrons to and less methane is formed.,” Nanda explains. In this scenario, the technology not only generates electricity but also solves an environmental problem and adds economic value to an area not necessarily considered very valuable. Nanda is careful to add that other sustainable energy sources will always be necessary, but that we should look carefully at which areas works best for which technologies. “If there’s a lot of wind, you’ll use turbines; if there’s a lot of sun, you’ll use solar panels; if there’s a lot of water and plants, you’ll use Plant-e – that’s the dream.”