MIT Claims Solar Energy
'Major discovery' from MIT primed to unleash solar
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.
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
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
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
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.