MIT news

'Major discovery' from MIT primed to unleash solar revolution

Scientists mimic essence of plants' energy storage system

Anne Trafton,
News Office
July 31, 2008
In a revolutionary leap that could transform solar power from
a marginal, boutique alternative into a mainstream energy source, MIT
researchers have overcome a major barrier to large-scale solar power:
storing energy for use when the sun doesn't shine.

Daniel Nocera describes new process for storing solar energy
View video post on MIT
TechTV
Until now, solar power has been a daytime-only energy source,
because storing extra solar energy for later use is prohibitively
expensive and grossly inefficient. With today's announcement, MIT
researchers have hit upon a simple, inexpensive, highly efficient
process for storing solar energy.
Requiring nothing but
abundant, non-toxic natural materials, this discovery could unlock the
most potent, carbon-free energy source of all: the sun. "This is the
nirvana of what we've been talking about for years," said MIT's Daniel Nocera, the Henry Dreyfus Professor of Energy at MIT and senior author of a
paper describing the work in the July 31 issue of Science. "Solar power
has always been a limited, far-off solution. Now we can seriously think
about solar power as unlimited and soon."
Inspired by the photosynthesis performed by plants, Nocera and Matthew Kanan, a postdoctoral fellow in Nocera's lab, have developed an unprecedented process that will allow the sun's
energy to be used to split water into hydrogen and oxygen gases. Later,
the oxygen and hydrogen may be recombined inside a fuel cell, creating
carbon-free electricity to power your house or your electric car, day
or night.
The key component in Nocera and Kanan's new process is
a new catalyst that produces oxygen gas from water; another catalyst
produces valuable hydrogen gas. The new catalyst consists of cobalt
metal, phosphate and an electrode, placed in water. When electricity
-- whether from a photovoltaic cell, a wind turbine or any other source
-- runs through the electrode, the cobalt and phosphate form a thin
film on the electrode, and oxygen gas is produced.
Combined with
another catalyst, such as platinum, that can produce hydrogen gas from
water, the system can duplicate the water splitting reaction that
occurs during photosynthesis.
The new catalyst works at room
temperature, in neutral pH water, and it's easy to set up, Nocera said.
"That's why I know this is going to work. It's so easy to implement,"
he said.

'Giant leap' for clean energy

Sunlight has the
greatest potential of any power source to solve the world's energy
problems, said Nocera. In one hour, enough sunlight strikes the Earth
to provide the entire planet's energy needs for one year.
James
Barber, a leader in the study of photosynthesis who was not involved in
this research, called the discovery by Nocera and Kanan a "giant leap"
toward generating clean, carbon-free energy on a massive scale.
"This
is a major discovery with enormous implications for the future
prosperity of humankind," said Barber, the Ernst Chain Professor of
Biochemistry at Imperial College London. "The importance of their
discovery cannot be overstated since it opens up the door for
developing new technologies for energy production thus reducing our
dependence for fossil fuels and addressing the global climate change
problem."

'Just the beginning'

Currently available
electrolyzers, which split water with electricity and are often used
industrially, are not suited for artificial photosynthesis because they
are very expensive and require a highly basic (non-benign) environment
that has little to do with the conditions under which photosynthesis
operates.
 
More engineering work needs to be done to integrate
the new scientific discovery into existing photovoltaic systems, but
Nocera said he is confident that such systems will become a reality.
 
"This
is just the beginning," said Nocera, principal investigator for the
Solar Revolution Project funded by the Chesonis Family Foundation and
co-director of the Eni-MIT Solar Frontiers Center. "The scientific community is really going to run with this."
Nocera
hopes that within 10 years, homeowners will be able to power their
homes in daylight through photovoltaic cells, while using excess solar
energy to produce hydrogen and oxygen to power their own household fuel
cell. Electricity-by-wire from a central source could be a thing of the
past.
The project is part of the MIT Energy Initiative, a program designed to help transform the global energy system to meet
the needs of the future and to help build a bridge to that future by
improving today's energy systems. MITEI Director Ernest Moniz, Cecil
and Ida Green Professor of Physics and Engineering Systems, noted that
"this discovery in the Nocera lab demonstrates that moving up the
transformation of our energy supply system to one based on renewables
will depend heavily on frontier basic science."
 
The success of
the Nocera lab shows the impact of a mixture of funding sources -
governments, philanthropy, and industry. This project was funded by the
National Science Foundation and by the Chesonis Family Foundation, which gave MIT $10 million this spring to launch the Solar Revolution Project, with a goal to make
the large scale deployment of solar energy within 10 years.

IMAGES

With Daniel Nocera's and Matthew Kanan's new
catalyst, homeowners could use their solar panels during the day to
power their home, while also using the energy to split water into
hydrogen and oxygen for storage. At night, the stored hydrogen and
oxygen could be recombined using a fuel cell to generate power while
the solar panels are inactive. Enlarge image