Dutch Company Powers Streetlights With Living Plants

from yesmagazine.org: In Hembrug, Netherlands, a crowd stood in a park and looked up into the
evening sky, waiting for lights to shine. This month more than 300 LED
lights were illuminated by the Dutch company Plant-e in a new energy
project called “Starry Sky.” Although the bulbs were ordinary, the electricity running through them derived from a new process that harnesses the power of living plants.

“Starry Sky” and a similar project an hour’s drive away, near
Plant-e’s Wageningen headquarters, are the two first commercial
installations of the company’s emerging technology. Both power
lighting, but the company also sells Wi-Fi hot spots, mobile chargers,
and rooftop electricity modules, all fueled by the byproducts of
living plants.

Plant-e’s co-founder and CEO, Marjolein Helder, believes that this
technology could be revolutionary. Using plants to generate electricity
brings a new clean energy option to the table, but even more
exciting, the company plans to expand the technology to existing
wetlands and rice paddies where electricity can be generated
on a
larger scale. This could give power to some of the world’s poorest

Although the idea of using plants and photosynthesis to extract energy
is not a new one—for decades middle schoolers have been engineering
clocks made from potatoes, which run on a similar
principle—Plant-e’s technology is the first to produce electricity from
plants without damaging them.

Helder was working on her master’s thesis in environmental technology
at Wageningen University when she first began to research plant energy.
She had aspirations to be an entrepreneur and agreed to research
the technology only if she could spend time each week pursuing her
business interests. The two endeavors came together when Helder
started working on a business case for what is now Plant-e.

Both projects that lit up the Netherlands this month involved native
aquatic plants that were supplied by local greenhouses. The process
involves plants growing in modules—two-square-foot plastic containers
connected to other modules—where they undergo the process of
photosynthesis and convert sunlight, air, and water into sugars. The
plants use some of the sugars to grow, but they also discharge a lot of
it back into the soil as waste. As the waste breaks down, it
releases protons and electrons. Plant-e conducts electricity by placing
electrodes into the soil.

Harvesting electricity from plants is no easy feat. Ramaraja
Ramasamy, an adjunct professor at the University of Georgia College of
Engineering, said that what Plant-e uses is called a “sediment
microbial fuel cell.” He cautions readers that this technology is not
advanced enough to compete with solar panels and wind turbines,
which have been in development for years.

“It’s not making enough energy to have any reliable commercial
product. That doesn’t mean that it will not be. We are too early in the
research,” Ramasamy explained. “If I come to you and say, ‘Do you
want to power that 100-watt bulb?’ You probably need an acre of land and
dirt to get the electricity from. Is that feasible? No.”

Although it may not be practical in the United States, where
households use high amounts of electricity, it could work in other parts
of the world.

Helder says that a one-square-meter garden should be able to produce
28 kilowatt-hours per year. According to the U.S. Energy Information
Administration, the average amount of electricity used by a home in a year was 10,837 kilowatt-hours in 2012.
This means in order to power a home in the United States, it would take
approximately 4,000 square feet of space, the size of a large backyard.

But in the Netherlands, the average household uses 3,500
kilowatt-hours of electricity per year, according to a press release
from Plant-e. This means a home in the Netherlands could be powered by
an area of Plant-e modules about a third of the size of what the U.S.
home would require.

As is the case with solar and wind energy, plant energy yields vary
based on climate. In the Netherlands, Plant-e’s installations stop
producing electricity for one to two weeks during the coldest part
of winter because the technology doesn’t work when the ground freezes.
As Plant-e expands to larger markets, this detail could dictate
where the product is best marketed.

The next step for Plant-e is using existing wetlands to generate
electricity. Engineers would place a tube horizontally below the surface
of a wetland, peat bog, mangrove, rice paddy, or river delta, and
use the same process as the modular system.

The company created a prototype tubular system last year and was
scheduled to start a pilot in July, but it ran into trouble with

“Modular systems are interesting, but you can only scale up to a
certain size because it’s pretty labor- and material-intensive,” Helder
said. “A tubular system can just be rolled out through the field and
it just works because the plants are already there. So for the longer
term, for the really large scale, that’s much more interesting.”

The tubular system is still years away from production. Helder said
that although the company hopes to start its field pilots soon, the
product will need two to three more years to complete the demo stage
and have a commercial product ready for market.

SOURCE: Yes Magazine

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