Redox flow batteries, a promising technology for renewable energies integration

ScienceDaily (Oct. 14, 2011) — Today there is a wide variety of energy storage technologies at very different stages of development. Among them, the Redox Flow Battery (RFB) is an innovative solution based on the use of liquid electrolytes stored in tanks and pumped through a reactor to produce energy. Tecnalia is currently working in the development of high performance RFBs.

RFB is, by its very nature, a modular and highly flexible technology with very rapid response, little environmental impact and considerable potential for cutting costs. This is the reason why Redox Flow Batteries are emerging as a very promising option for stationary storage in general and for renewable applications in particular.

Renewable energies

There is no doubt that the development of renewable energies will be a key milestone in the way towards a new environmentally-friendly energy model., However, their variability and limited predictability are posing a problem for the operation of the system and, as a result, a barrier to their massive penetration.

A clear example of these difficulties is the need to maintain backup systems that generate energy during low wind or low solar irradiance periods. On the other side, high renewable generation can lead to energy waste during low demand periods.

Redox Flow Batteries are considered as a highly adequate technology to mitigate the variability of renewable energies and to improve their dispatchability, that is, to provide the capability to regulate the output in a similar way to conventional power stations. The energy stored during periods of high renewable production can be used to compensate for the lack of generation when the weather conditions are less favourable.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Elhuyar Fundazioa.

Note: If no author is given, the source is cited instead.

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‘Cling-film’ solar cells could lead to advance in renewable energy

ScienceDaily (July 4, 2011) — A scientific advance in renewable energy which promises a revolution in the ease and cost of using solar cells, has been announced on July 4, 2011. A new study shows that even when using very simple and inexpensive manufacturing methods -- where flexible layers of material are deposited over large areas like cling-film -- efficient solar cell structures can be made.

The study, published in the journal Advanced Energy Materials, paves the way for new solar cell manufacturing techniques and the promise of developments in renewable solar energy. Scientists from the Universities of Sheffield and Cambridge used the ISIS Neutron Source and Diamond Light Source at STFC Rutherford Appleton Laboratory in Oxfordshire to carry out the research.

Plastic (polymer) solar cells are much cheaper to produce than conventional silicon solar cells and have the potential to be produced in large quantities. The study showed that when complex mixtures of molecules in solution are spread onto a surface, like varnishing a table-top, the different molecules separate to the top and bottom of the layer in a way that maximises the efficiency of the resulting solar cell.

Dr Andrew Parnell of the University of Sheffield said, "Our results give important insights into how ultra-cheap solar energy panels for domestic and industrial use can be manufactured on a large scale. Rather than using complex and expensive fabrication methods to create a specific semiconductor nanostructure, high volume printing could be used to produce nano-scale (60 nano-meters) films of solar cells that are over a thousand times thinner than the width of a human hair. These films could then be used to make cost-effective, light and easily transportable plastic solar cell devices such as solar panels."

Dr. Robert Dalgliesh, one of the ISIS scientists involved in the work, said, "This work clearly illustrates the importance of the combined use of neutron and X-ray scattering sources such as ISIS and Diamond in solving modern challenges for society. Using neutron beams at ISIS and Diamond's bright X-rays, we were able to probe the internal structure and properties of the solar cell materials non-destructively. By studying the layers in the materials which convert sunlight into electricity, we are learning how different processing steps change the overall efficiency and affect the overall polymer solar cell performance. "

"Over the next fifty years society is going to need to supply the growing energy demands of the world's population without using fossil fuels, and the only renewable energy source that can do this is the Sun," said Professor Richard Jones of the University of Sheffield. " In a couple of hours enough energy from sunlight falls on the Earth to satisfy the energy needs of the Earth for a whole year, but we need to be able to harness this on a much bigger scale than we can do now. Cheap and efficient polymer solar cells that can cover huge areas could help move us into a new age of renewable energy."

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Science and Technology Facilities Council (STFC).

Journal Reference:

Paul A. Staniec, Andrew J. Parnell, Alan D. F. Dunbar, Hunan Yi, Andrew J. Pearson, Tao Wang, Paul E. Hopkinson, Christy Kinane, Robert M. Dalgliesh, Athene M. Donald, Anthony J. Ryan, Ahmed Iraqi, Richard A. L. Jones, David G. Lidzey. The Nanoscale Morphology of a PCDTBT:PCBM Photovoltaic Blend. Advanced Energy Materials, 2011; DOI: 10.1002/aenm.201100144

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Splitting water for renewable energy simpler than first thought? Manganese-based catalyst shows promise

ScienceDaily (May 18, 2011) — An international team, of scientists, led by a team at Monash University has found the key to the hydrogen economy could come from a very simple mineral, commonly seen as a black stain on rocks.

Their findings, developed with the assistance of researchers at UC Davis in the USA and using the facilities at the Australian Synchrotron, was published in the journal Nature Chemistry on May 15, 2011.

Professor Leone Spiccia from the School of Chemistry at Monash University said the ultimate goal of researchers in this area is to create a cheap, efficient way to split water, powered by sunlight, which would open up production of hydrogen as a clean fuel, and leading to long-term solutions for our renewable energy crisis.

To achieve this, they have been studying complex catalysts designed to mimic the catalysts plants use to split water with sunlight. But the new study shows that there might be much simpler alternatives to hand.

"The hardest part about turning water into fuel is splitting water into hydrogen and oxygen, but the team at Monash seems to have uncovered the process, developing a water-splitting cell based on a manganese-based catalyst," Professor Spiccia said.

"Birnessite, it turns out, is what does the work. Like other elements in the middle of the Periodic Table, manganese can exist in a number of what chemists call oxidation states. These correspond to the number of oxygen atoms with which a metal atom could be combined," Professor Spiccia said.

"When an electrical voltage is applied to the cell, it splits water into hydrogen and oxygen and when the researchers carefully examined the catalyst as it was working, using advanced spectroscopic methods they found that it had decomposed into a much simpler material called birnessite, well-known to geologists as a black stain on many rocks."

The manganese in the catalyst cycles between two oxidation states. First, the voltage is applied to oxidize from the manganese-II state to manganese-IV state in birnessite. Then in sunlight, birnessite goes back to the manganese-II State.

This cycling process is responsible for the oxidation of water to produce oxygen gas, protons and electrons.

Co-author on the research paper was Dr Rosalie Hocking, Research Fellow in the Australian Centre for Electromaterials Science who explained that what was interesting was the operation of the catalyst, which follows closely natures biogeochemical cycling of manganese in the oceans.

"This may provide important insights into the evolution of Nature's water splitting catalyst found in all plants which uses manganese centres," Dr Hocking said.

"Scientists have put huge efforts into making very complicated manganese molecules to copy plants, but it turns out that they convert to a very common material found in the Earth, a material sufficiently robust to survive tough use."

The reaction has two steps. First, two molecules of water are oxidized to form one molecule of oxygen gas (O2), four positively-charged hydrogen nuclei (protons) and four electrons. Second, the protons and electrons combine to form two molecules of hydrogen gas (H2).

The experimental work was conducted using state-of-the art equipment at three major facilities including the Australian Synchrotron, the Australian National Beam-line Facility in Japan and the Monash Centre for Electron Microscopy, and involved collaboration with Professor Bill Casey, a geochemist at UC Davis.

"The research highlights the insight obtainable from the synchrotron based spectroscopic techniques -- without them the important discovery linking common earth materials to water oxidation catalysts would not have been made," Dr Hocking said.

It is hoped the research will ultimately lead to the development of cheaper devices, which produce hydrogen.

The work was primarily funded by the U.S. National Science Foundation and the U.S. Department of Energy Monash University, the Australian Research Council through the Australian Centre of Excellence for Electromaterials Science, and the Australian Synchrotron.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Monash University.

Journal Reference:

Rosalie K. Hocking, Robin Brimblecombe, Lan-Yun Chang, Archana Singh, Mun Hon Cheah, Chris Glover, William H. Casey, Leone Spiccia. Water-oxidation catalysis by manganese in a geochemical-like cycle. Nature Chemistry, 2011; DOI: 10.1038/nchem.1049

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Splitting water for renewable energy simpler than first thought? Manganese-based catalyst shows promise

ScienceDaily (May 18, 2011) — An international team, of scientists, led by a team at Monash University has found the key to the hydrogen economy could come from a very simple mineral, commonly seen as a black stain on rocks.

Their findings, developed with the assistance of researchers at UC Davis in the USA and using the facilities at the Australian Synchrotron, was published in the journal Nature Chemistry on May 15, 2011.

Professor Leone Spiccia from the School of Chemistry at Monash University said the ultimate goal of researchers in this area is to create a cheap, efficient way to split water, powered by sunlight, which would open up production of hydrogen as a clean fuel, and leading to long-term solutions for our renewable energy crisis.

To achieve this, they have been studying complex catalysts designed to mimic the catalysts plants use to split water with sunlight. But the new study shows that there might be much simpler alternatives to hand.

"The hardest part about turning water into fuel is splitting water into hydrogen and oxygen, but the team at Monash seems to have uncovered the process, developing a water-splitting cell based on a manganese-based catalyst," Professor Spiccia said.

"Birnessite, it turns out, is what does the work. Like other elements in the middle of the Periodic Table, manganese can exist in a number of what chemists call oxidation states. These correspond to the number of oxygen atoms with which a metal atom could be combined," Professor Spiccia said.

"When an electrical voltage is applied to the cell, it splits water into hydrogen and oxygen and when the researchers carefully examined the catalyst as it was working, using advanced spectroscopic methods they found that it had decomposed into a much simpler material called birnessite, well-known to geologists as a black stain on many rocks."

The manganese in the catalyst cycles between two oxidation states. First, the voltage is applied to oxidize from the manganese-II state to manganese-IV state in birnessite. Then in sunlight, birnessite goes back to the manganese-II State.

This cycling process is responsible for the oxidation of water to produce oxygen gas, protons and electrons.

Co-author on the research paper was Dr Rosalie Hocking, Research Fellow in the Australian Centre for Electromaterials Science who explained that what was interesting was the operation of the catalyst, which follows closely natures biogeochemical cycling of manganese in the oceans.

"This may provide important insights into the evolution of Nature's water splitting catalyst found in all plants which uses manganese centres," Dr Hocking said.

"Scientists have put huge efforts into making very complicated manganese molecules to copy plants, but it turns out that they convert to a very common material found in the Earth, a material sufficiently robust to survive tough use."

The reaction has two steps. First, two molecules of water are oxidized to form one molecule of oxygen gas (O2), four positively-charged hydrogen nuclei (protons) and four electrons. Second, the protons and electrons combine to form two molecules of hydrogen gas (H2).

The experimental work was conducted using state-of-the art equipment at three major facilities including the Australian Synchrotron, the Australian National Beam-line Facility in Japan and the Monash Centre for Electron Microscopy, and involved collaboration with Professor Bill Casey, a geochemist at UC Davis.

"The research highlights the insight obtainable from the synchrotron based spectroscopic techniques -- without them the important discovery linking common earth materials to water oxidation catalysts would not have been made," Dr Hocking said.

It is hoped the research will ultimately lead to the development of cheaper devices, which produce hydrogen.

The work was primarily funded by the U.S. National Science Foundation and the U.S. Department of Energy Monash University, the Australian Research Council through the Australian Centre of Excellence for Electromaterials Science, and the Australian Synchrotron.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Monash University.

Journal Reference:

Rosalie K. Hocking, Robin Brimblecombe, Lan-Yun Chang, Archana Singh, Mun Hon Cheah, Chris Glover, William H. Casey, Leone Spiccia. Water-oxidation catalysis by manganese in a geochemical-like cycle. Nature Chemistry, 2011; DOI: 10.1038/nchem.1049

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here