MIT scientists have come up with a new solar energy they believe will replace conventional storage technology.

A new revolution in solar power is set to bring energy from the sun into the night. A major barrier to large-scale solar power is having a way to store the sun’s energy so that it can be used at night or when skies are cloudy.

Solar power has historically been restricted to being a daytime source of energy as conventional photovoltaic solar panels produce energy only when the sun is shining. Storing solar energy for use at night has been expensive and inefficient. However, the Massachussettes Institute of Technology, or MIT, has announced that they have developed a simple, inexpensive, and very efficient solar energy storage process.

“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.”

Requiring only non-toxic natural materials that are available in abundance, this discovery could unlock the most potent, carbon-free energy source of all: the sun.

The key to the discovery is that it was inspired by the process of photosynthesis in plants. Nocera and Matthew Kanan, a post-doctoral 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.

Nocera and Kanan’s process uses as it’s key component a new catalyst that produces oxygen gas from liquid water; another catalyst produces hydrogen gas. The catalyst, composed of cobalt metal, phosphate and an electrode, are placed in water. Electricity from a PV panel or wind turbine or any other source of electricity runs through the electrode,  the cobalt and phosphate form a thin film on the electrode, and oxygen gas is produced.

When combined with another catalyst that can produce hydrogen gas from water, such as platinum, the new process can mimic the water splitting reaction that occurs during photosynthesis.

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The process is very easy to set up, according to Nocera. “That’s why I know this is going to work. It’s so easy to implement,” he said.

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.

“This is a major discovery with enormous implications for the future prosperity of humankind,” said James 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.”
Barber, a leader in the study of photosynthesis, called the discovery by Nocera and Kanan a “giant leap” toward generating clean, carbon-free energy on a massive scale.

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.

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.

“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 beleives that electricity from a central grid 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. Ernest Moniz, MITEI Director and Professor of Physics and Engineering Systems, opined 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.”