As humans scour the Earth for energy, venturing farther
offshore and deeper underground, a new study suggests the answer has been under
our noses all along. Rather than chasing finite fossils like oil and coal, it
focuses on Earth's original power plants: plants.
Plants
use energy from the Sun through photosynthesis, and humans use energy from the
Sun through things like solar panels. A
new technique created by researchers at the University of Georgia allows humans
to get electricity from plants by breaking the Process of photosynthesis. This
research could someday lead to some very literal power plants.
Solar panels seem to be a good option for generating
electricity, but the reality of the situation is that they’re terribly
inefficient at generating power from sunlight. Thanks to eons of evolution,
most plants operate at 100 percent quantum efficiency, They convert nearly 100
percent of the photons they capture from sunlight into electrons, which go
through a series of reactions on the pathway to generating sugars, the team
behind the technology explained. meaning they produce an equal number of
electrons for every photon of sunlight they capture in photosynthesis. An
average coal-fired power plant, meanwhile, only operates at about 28 percent
efficiency, and it carries extra baggage like mercury and carbon dioxide
emissions. Even our best large-scale imitations of photosynthesis —
photovoltaic solar panels — typically operate at efficiency levels of just 12
to 17 percent. Plants divide water molecules into hydrogen and oxygen through
photosynthesis, and when this split occurs, electrons are generated. Typically,
these electrons are used by the plants to create sugar used to grow and reproduce.
The team at the University of Georgia have developed a way to use carbon
nanotubes to capture those electrons before they’re used by the plant. This
isn’t the first experiment that’s used plants to generate electricity, but it’s
at least two orders or magnitude more electrical current than earlier work.
It’s going to take more research before this is a commercially viable
technology, and at the moment it’s best suited for powering things like remote
sensors and portable electronics. One of the researchers, Ramaraja Ramasamy, compares his work
to hydrogen fuel cells, saying, “The electrical output we see now is modest,
but only about 30 years ago, hydrogen fuel cells were in their infancy, and now
they can power cars, buses and even buildings.”Photosynthesis is arguably one
of the most important natural processes in the entire world. Experts say that
it is mainly to praise for the development of a breathable atmosphere.
Basically, it's constituted from a range of complex chemical reactions, which
see the conversion of carbon dioxide (CO2) and water into glucose (energy) and
oxygen (O2), all in the presence of visible light. While the initial atmosphere
surrounding our planet was laden with volcano-produced carbon, the earliest
plants did a monumental job at clearing the air for the more complex lifeforms
that followed.
The secret lies in thylakoids, the membrane-bound sacs inside a plant's chloroplasts (pictured at bottom) that capture and store energy from sunlight. By manipulating the proteins inside thylakoids, Ramasamy and his colleagues can interrupt the flow of electrons produced during photosynthesis. They can then restrain the modified thylakoids in a specially designed backing of carbon nanotubes, which captures the plant's electrons and serves as an electrical conductor, sending them along a wire to be used elsewhere. He and his colleagues do this by extracting the plant machinery that drives the photosynthetic reaction called thylakoids and immobilizing them on a bed of carbon nanotubes, which act as an electrical conductor, capturing the electrons and sending them along a wire.
The secret lies in thylakoids, the membrane-bound sacs inside a plant's chloroplasts (pictured at bottom) that capture and store energy from sunlight. By manipulating the proteins inside thylakoids, Ramasamy and his colleagues can interrupt the flow of electrons produced during photosynthesis. They can then restrain the modified thylakoids in a specially designed backing of carbon nanotubes, which captures the plant's electrons and serves as an electrical conductor, sending them along a wire to be used elsewhere. He and his colleagues do this by extracting the plant machinery that drives the photosynthetic reaction called thylakoids and immobilizing them on a bed of carbon nanotubes, which act as an electrical conductor, capturing the electrons and sending them along a wire.
"That
way, you have a continuous flow of electrons when the light is falling on the
photosynthetic machinery from the plant," Ramasamy said, adding that the
energy conversion technology is similar to a fuel cell, only in this case the
fuel is sunlight. Similar systems have been developed before, but Ramasamy's
has so far generated significantly stronger electrical currents, measuring two
orders of magnitude larger than previous methods. It's still far too little
power for most commercial uses, he points out, but his team is already working
to boost its output and stability. Although carbon nanotubes are key to
this method of harnessing sunlight, they can also have a dark side. The tiny
cylinders, which are nearly 50,000 times finer than a human hair, have been
implicated as potential health risks for anyone who inhales them, since they can become lodged in the lungs
much like asbestos, a known carcinogen. But recent redesigns have reduced their
harmful effects on lungs, based on research that shows shorter nanotubes produce less lung irritation than longer fibers do. Ramasamy says
of his study. "The electrical output we see now is modest, but only about
30 years ago, hydrogen fuel cells were in their infancy, and now they can power
cars, buses and even buildings."
"What
we are trying to do is interrupt the pathway of natural photosynthesis and then
trying to deal with those electrons," Ramaraja Ramasamy, an electrochemist at the University of Georgia, told
NBC News.The efficiency of the system has the potential to be much greater than
solar panels, which convert between 12 and 17 percent of the sunlight that hits
them into electricity. First, though, more work needs to be done to improve the
stability of the system. Currently,
taking the thylakoids out of a plant is akin to taking the heart out of a human
— it is not stable for very long, Ramasamy noted. But plants have a mechanism
to replenish their photosynthetic machinery. It may be possible, he said, to
genetically engineer this machinery for long-term stability.
"That's
the direction this has to be explored in much more detail," he said.If
successful, potential applications for the technology, at least in the near to
medium term, include use as a power source for sensors used in remote
locations, eliminating the need for batteries. Ramasamy and colleagues recently
described a proof-of-concept device in the journal Energy and
Environmental Science.
"It is green energy, 100 percent clean, it has the potential to operate at
really high efficiency, if we can continue to improve on this," Ramasamy
said.
In
the new achievement, French scientists at the Centre de Recherche Paul Pascal
(CNRS) developed a new type of biofuel cell, that functions based on the two
compounds that result following natural photo photosynthesis, and namely glucose
and oxygen. The system's design is very basic, as it is composed of two
electrodes, that have been altered using enzymes. What's also amazing is the
fact that the team managed to insert one such cell into the leaf, or spike, of
a living cactus, and then watch the chemical reaction take place in vivo –
which means that they observed it while the plant was alive. The discovery
could also be used in botanical research, so that experts working in this area
can better understand how photosynthesis acts. In their observation, the CNRS
experts also noticed the variable levels of glucose that were produced as light
struck the biofuel cells. This is the first time such an observation is
conducted, they say. It was additionally revealed that a single one of the new
cells, inserted in a cactus leaf, could produce as much as 9 Watts of
electricity per square centimeter. But one of the main applications for the new
cells is as power source for medical devices, as they are able to function in
live subjects. Placed under the skin, they could benefit from enough light to
produce the necessary amounts of electricity to power up a variety of medical
implants. olar power could transform the energy landscape in the United States,
reducing the nation's reliance on coal and natural gas for electricity. Today,
however, solar power remains more expensive on average than fossil fuels.
"You
may think that the sun is abundant, but traditional photovoltaics require
rare-earth elements, and a lot of them are imported from areas that have wars
or where it is difficult to extract, which raises the cost," says Margaret
Cheung, Assistant Professor of Physics at the University of Houston. She notes
that if we learn from plants, which use only common elements—hydrogen,
nitrogen, carbon, oxygen and some others—to convert sunlight into energy, then
we’ll be able to bring down the cost of solar power. This is why researchers
are looking at bio-inspired materials as possible resources for solar energy.
Study co-author and UGA engineering professor Ramaraja
Ramasamy says in a press release.
"Clean energy is the need of the century. This approach may one day
transform our ability to generate cleaner power from sunlight using plant-based
systems."
Figure 1. Detailed Inside View of Plant
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