[Graeme]

The Burning Answer: a User's Guide to the Solar Revolution by Keith Barnham

Barnham is a leading researcher and developer of silicon solar cells and, for a while, his team held the world record for the most efficient version of this rapidly improving technology. He is not an ivory-tower scientist and has worked to commercialise his discoveries – but he has come up against the chronic failure of British industry and finance to nurture such innovative technology.

He has a conceit to make the point about solar versus fossil and nuclear fuels. Imagine there really are more advanced civilisations in the universe than ours: the reason we've never heard from them is that they've taken one look at earth, where we are still burning fossil fuels and uranium instead of using solar power, and decided that "earthlings are too stupid to be worth colonising".

Propagandists for fossil fuels and nuclear power have tried to discredit renewable energy with lazy, superficially plausible objections: in a country like Britain there's not sufficient sun, the wind doesn't always blow, and so on. But, as with all science, common sense is a poor guide. Barnham demonstrates that even in northern countries there is quite enough renewable energy available. Indeed, the Scandinavian countries plus Germany are the leaders in renewables, with Iceland (geothermal) and Norway (hydroelectric) close to 100% in renewable electricity generation. If they can do it, so can Britain.

Barnham proposes a combination of technologies. As a leading photovoltaic solar cell inventor, he gives this pride of place, along with onshore wind, biogas from waste food and underground heat pumps. The last two are the least familiar but perhaps most promising for filling the gaps when the sun doesn't shine and the wind doesn't blow. In Sweden more than 90% of new homes have ground source heat pumps installed: just two metres down the ground retains sufficient warmth to provide hot water for a house via reverse refrigeration technology. Biogas technology puts to use the methane from household waste. Instead of adding to global warming by dumping waste in landfill (methane is 25 times more potent a greenhouse gas than CO2) it can be used either to supplement natural gas to generate electricity or for domestic heating and cooking.

Perhaps the most important of all Barnham's correctives to the received wisdom on energy sources is his stress on developing biofuels from the very CO2 that is tipping the world's climate into the danger zone. Carbon dioxide is the source of all living plant material (biomass) and fossil fuels. The best-known technology for reducing CO2 emissions at source is carbon capture and storage, but why pay to bury it when it could be put to use? To do this we have to learn what every leaf knows: how to turn sunlight, CO2 and water into biomass.

The race to mimic nature's two photosystems is the greatest scientific challenge of our time, the Manhattan Project and the Moonshot rolled into one: far more important in fact but not necessarily more expensive or more demanding of resources or ingenuity. Unravelling nature's mechanism is almost complete – an achievement arguably as great as DNA sequencing but, astonishingly, so far unknown to almost everyone. One of the pioneers is Barnham's colleague at Imperial College, James Barber.

theguardian

[rollin]

If you want carbon capture and storage just encourage re-forestation on a global scale. Eventually, after a thousand years or so, the ocean will have given up much of it's extra CO2 and we will be on our way back to the ice age cycle again.

Any carbon sequestration program needs to run for at least one millennia, possibly two. So using industrial methods will most likely not work out.

[efarmer]

Selenium cell in 1830's, silicon cells in 1940's, mono and poly silicon cells for decades, organic solar research since the early 1960's. Let's say full court press on solar R&D for 50 years now at least. The burning answer is that this chap is desperate for funding in a field that has had huge seed money applied and always comes to the conclusion that solar cells are high maintenance, fragile, and expensive compared with alternatives when possible, when not possible, solar cells are just fine. I throw in with Rollin, organic life with procreation and evolution available to it scales over the required time and wins the game
with the variable being we don't get to make money or see it's results in our time horizons.

[Graeme]

In the US, research into artificial photosynthesis is occurring at the Joint Center for Artificial Photosynthesis in California.

Overview

The Joint Center for Artificial Photosynthesis (JCAP) is the nation’s largest research program dedicated to the development of an artificial solar-fuel generation technology. Established in 2010 as a U.S. Department of Energy (DOE) Energy Innovation Hub, JCAP aims to find a cost-effective method to produce fuels using only sunlight, water, and carbon dioxide as inputs. JCAP is led by a team from the California Institute of Technology (Caltech) and brings together more than 120 world-class scientists and engineers from Caltech and its lead partner, Lawrence Berkeley National Laboratory. JCAP also draws on the expertise and capabilities of key partners from Stanford University, the University of California campuses at Berkeley (UCB), Irvine (UCI), and San Diego (UCSD), and the Stanford Linear Accelerator (SLAC). In addition, JCAP serves as a central hub for other solar fuels research teams across the United States, including 20 DOE Energy Frontier Research Centers.

JCAP’s Mission

The development of a renewable fuel source that can meet the nation's energy demand while reducing carbon dioxide emissions is critical to the energy security, environmental protection, and economic well-being of the United States. JCAP's mission is to develop a manufacturable solar-fuels generator, made of Earth-abundant elements, that will use only sunlight, water, and carbon dioxide as inputs and robustly produce fuel from the sun ten times more efficiently than current crops. Such an achievement would minimize trade-offs between food and fuel, would allow for installation of the systems in a diverse range of sites and environments, and would provide the direct production of a useful chemical fuel from the sun.

Please view their "fact sheet".

Today, JCAP is seeking new ways to produce carbon-neutral transportation fuels, including hydrogen, methanol, and fuels with high energy density for aircraft and other specialized vehicles, using only sunlight, water, and carbon dioxide as inputs. Artificial photosynthesis, once achieved and scaled up, could be significantly more efficient than biofuel production processes, and would not require arable land, agricultural feedstock, or substantial inputs of energy or water.

Please view wiki article:

Photobiological production of fuels

Some photoautotrophic microorganisms can, under certain conditions, produce hydrogen. Nitrogen-fixing microorganisms, such as filamentous cyanobacteria, possess the enzyme nitrogenase, responsible for conversion of atmospheric N2 into ammonia; molecular hydrogen is a byproduct of this reaction, and is many times not released by the microorganism, but rather taken up by a hydrogen-oxidizing (uptake) hydrogenase. One way of forcing these organisms to produce hydrogen is then to annihilate uptake hydrogenase activity. This has been done on a strain of Nostoc punctiforme: one of the structural genes of the NiFe uptake hydrogenase was inactivated by insertional mutagenesis, and the mutant strain showed hydrogen evolution under illumination.[64]

Many of these photoautotrophs also have bidirectional hydrogenases, which can produce hydrogen under certain conditions. However, other energy-demanding metabolic pathways can compete with the necessary electrons for proton reduction, decreasing the efficiency of the overall process; also, these hydrogenases are very sensitive to oxygen.[10]

Several carbon-based biofuels have also been produced using cyanobacteria, such as 1-butanol.[65]

Synthetic biology techniques are predicted to be useful in this field. Microbiological and enzymatic engineering have the potential of improving enzyme efficiency and robustness, as well as constructing new biofuel-producing metabolic pathways in photoautotrophs that previously lack them, or improving on the existing ones.[10][65] Another field under development is the optimization of photobioreactors for commercial application.[66]

Nature reviewed "artifical leaf" two years ago, Chemistryworld a year later, then NYTimes and CNN this year.

[efarmer]

Good to see the research continuing and getting funded. The keywords are "once achieved and scaled up". I do not protest against science Graeme, I do feel that it has to be treated like a source of solutions rather than the total sum of miracle marbles we have to play with.

[Graeme]

Just saw the following article on recent research on artificial photosynthesis. Application of such systems is not far away.

Hybrid energy transfer system mimics process responsible for photosynthesis

Scientists have developed a new hybrid energy transfer system, which mimics the processes responsible for photosynthesis. From photosynthesis to respiration, the processes of light absorption and its transfer into energy represent elementary and essential reactions that occur in any biological living system. In a new study, researchers demonstrate an alternate non-radiative, intermolecular energy transfer that exploits the intermediating role of light confined in an optical cavity.


"On the applied perspective instead, organic semiconductors continue to receive significant interest for application in optoelectronic devices, for example light-emitting or photovoltaic devices, in which performance is dependent on our ability to control the formation and transport of carriers in molecular systems."

sciencedaily

[Graeme]

Artificial photosynthesis gets a boost

A new thin-film coating made from titanium dioxide could convert sunlight to a zero-emission fuel more efficiently.

The findings, from a paper in this week's issue of Science, bring the dream of artificial photosynthesis one step closer, says author Nathan Lewis, a chemistry professor, specialising in solar fuels at Caltech.

Solar panels convert sunlight into usable energy, but a major aim of sustainable energy researchers is to convert sunlight into storable chemical fuels such as hydrogen.

Plants already convert solar into chemical energy using the process of photosynthesis, but this natural process is very inefficient, says Lewis.

"Less than 1 per cent of the energy in the sunlight that strikes the plant is stored in the biomass of the plant," he says.

"So we're trying to build systems that are 10 times more efficient, but that are also robust, last a long time and are cost effective."

The aim would be to have solar fuel generators on rooftops and in fields producing liquid or gas fuels for cars, buildings and industry.

abc

[Graeme]

Water and sunlight: The formula for sustainable fuel

An Australian National University (ANU) team has successfully replicated one of the crucial steps in photosynthesis, opening the way for biological systems powered by sunlight which could manufacture hydrogen as a fuel.

Water is abundant and so is sunlight. It is an exciting prospect to use them to create hydrogen, and do it cheaply and safely," said Dr Kastoori Hingorani, from the ARC Centre of Excellence for Translational Photosynthesis in the ANU Research School of Biology.

Hydrogen offers potential as a zero-carbon replacement for petroleum products, and is already used for launching space craft. However, until this work, the way that plants produce hydrogen by splitting water has been poorly understood.

The team created a protein which, when exposed to light, displays the electrical heartbeat that is the key to photosynthesis.

The system uses a naturally-occurring protein and does not need batteries or expensive metals, meaning it could be affordable in developing countries, Dr Hingorani said.

Co-researcher Professor Ron Pace said the research opened up new possibilities for manufacturing hydrogen as a cheap and clean source of fuel.

"This is the first time we have replicated the primary capture of energy from sunlight," Professor Pace said.

"It's the beginning of a whole suite of possibilities, such as creating a highly efficient fuel, or to trapping atmospheric carbon."

Professor Pace said large amounts of hydrogen fuel produced by artificial photosynthesis could transform the economy.

sciencedaily

[Graeme]

On the road to artificial photosynthesis: Study reveals key catalytic factors in carbon dioxide reduction

The excessive atmospheric carbon dioxide that is driving global climate change could be harnessed into a renewable energy technology that would be a win for both the environment and the economy. That is the lure of artificial photosynthesis in which the electrochemical reduction of carbon dioxide is used to produce clean, green and sustainable fuels. However, finding a catalyst for reducing carbon dioxide that is highly selective and efficient has proven to be a huge scientific challenge. Meeting this challenge in the future should be easier thanks to new research results from Berkeley Lab.

Peidong Yang, a chemist with Berkeley Lab's Materials Sciences Division, led a study in which bimetallic nanoparticles of gold and copper were used as the catalyst for the carbon dioxide reduction. The results experimentally revealed for the first time the critical influence of the electronic and geometric effects in the reduction reaction.

"Acting synergistically, the electronic and geometric effects dictate the binding strength for reaction intermediates and consequently the catalytic selectivity and efficiency in the electrochemical reduction of carbon dioxide," Yang says. "In the future, the design of carbon dioxide reduction catalysts with good activity and selectivity will require the careful balancing of these two effects as revealed in our study."

phys.org

[Graeme]

Scientists are a step closer to “Holy Grail” of turning carbon dioxide into fuel

Scientists have spent decades trying to replicate photosynthesis - the reaction that allows plants to convert carbon dioxide, water and sunshine into the sugar that fuels its growth. If we can work out how to replicate “artificial photosynthesis”, we would essentially be able to easily and cheaply create biofuels from the excess carbon dioxide in our atmosphere. But it’s proved to be an extremely difficult process to copy.

Now scientists from the Lawrence Berkeley National Laboratory in the US have achieved a breakthrough in the process - they’ve identified two key factors that will need to be considered when creating a catalyst that reduces carbon dioxide and helps drive its conversion into sugar.
A catalyst is a substance that speeds up a reaction without undergoing any chemical change itself, and so far finding a catalyst that will bind selectively and efficiently to carbon dioxide and the molecules that it breaks down into has proven extremely tough. To find out more about the factors that might influence the "ideal" catalyst, the research team created a range of alloys from gold-copper bimetallic nanoparticles.

These alloys all had different compositions, and they measured which ones were most effective at breaking down carbon dioxide and its intermediate products, such as carboxylic acid and carbon monoxide.

What they found is that there are two key, interlinked factors involved in the success of a catalyst - the electronic and geometric effects. The electronic effect refers to slight changes in surface composition that will alter how well a molecule will bind with a catalyst, while the geometric effect involves the arrangement of the atoms at the binding site.

sciencealert