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Scientists Explore How the Humble Leaf Could Power the Planet
Researchers at Imperial College London embark on 'artificial leaf' project to produce power by mimicking photosynthesis
It is one of evolution's crowning achievements - a mini green power station and organic factory combined and the source of almost all of the energy that fuels every living thing on the planet.
Scientists hope to be able to mimic one of evolution's crowning achievements: leaves. (Photograph: Graeme Robertson) Now
scientists developing the next generation of clean power sources are
working out how to copy, and ultimately improve upon, the humble leaf.
The intricate chemistry involved in photosynthesis, the process where plants
use sunlight to convert water and carbon dioxide into sugar, is the
most effective solar energy conversion process on Earth. And
researchers believe that mimicking parts of it could be the ticket to a
limitless supply of clean power.
The untapped potential for using the sun's rays is huge. All human activity for a whole year could be powered by the energy contained in the sunlight hitting the Earth in just one hour. Harnessing even a small amount of this to make electricity or useful fuels could satisfy the world's increasing need for energy, predicted to double by 2050, without further endangering the climate.
Most solar power systems use silicon wafers to generate electricity directly. But although costs are coming down, these are still too expensive in many cases when compared with fossil fuels such as coal, oil and gas. Scientists are keen to develop more efficient and cheaper alternatives sources of energy.
At Imperial College London, researchers have embarked on a £1m project to study, and eventually mimic, photosynthesis. Part of a project called the "artificial leaf", involves working out exactly how leaves use sunlight to make useful molecules. The team then plans to build artificial systems that can do the same to generate clean fuels such as hydrogen and methanol. These would then be used in fuel cells to make electricity or directly to power super-clean vehicles.
Similar projects are gathering pace around the world: the US is poised to approve a federal research budget of around $35m a year for ideas that could create fuels from sunlight and the Dutch government has allocated €40m for similar research.
According to James Barber, a biologist at Imperial College London and leader of the artificial leaf project, if artificial photosynthesis systems could use around 10% of the sunlight falling on them, they would only need to cover 0.16% of the Earth's surface to satisfy a global energy consumption rate of 20 terawatts, the amount it is predicted that the world will need in 2030. And unlike a biological leaf, the artificial equivalent could be placed in the arid desert areas of the world, where it would not compete for space agricultural land.
Ultimately, Barber hopes to improve on nature's own solar cell. "If the leaf can do it, we can do it but even better," he said. "[But] it doesn't mean that you try to build exactly what the leaf has. Leonardo da Vinci tried to design flying machines with feathers that flapped up and down. But in the end we built 747s and Airbus 380s, completely different to a bird and, in fact, even better than a bird."
Photosynthesis starts with a chemical reaction where sunlight is used to split water into hydrogen and oxygen. The oxygen is released into the atmosphere while the hydrogen is used to create sugars and other organic molecules for the plant. The aim of Barber's artificial leaf project is to find an efficient way of mimicking that water-splitting reaction to create a clean and limitless source hydrogen. Unlike normal leaves, the new devices would not suck CO2 out of the atmosphere.
Hydrogen is a clean, energy-rich fuel that could be used in fuel cells to make electricity or else combined with carbon dioxide from the atmosphere (or from the exhaust of fossil-fuel power stations) to make methanol, a fuel that could be dropped into vehicles without the need for any engine modifications. "The challenge is to get hydrogen out of water using a ready supply of energy," said Barber.
For domestic purposes, Dan Nocera, a chemist at the Massachusetts Institute of Technology, has calculated that using artificial leaf to split a few litres of water a day into hydrogen and oxygen would be enough to supply all a home's energy needs.
Scientists can already produce hydrogen by splitting water but current techniques are expensive, use harsh chemicals and need carefully controlled environments in which to operate. The critical part of the artificial leaf project is developing catalysts made from cheap materials that can be used to split water in everyday conditions.
John Loughhead, executive director of the UK Energy Research Centre, described the artificial leaf idea as very promising because "we know that plants have already evolved to do it and we know that, fundamentally, it's a workable process on a large scale."
He added: "Ultimately, the only sustainable form of energy we've got is the sun. From a strategic viewpoint, you have to think this looks really interesting because we know we're starting from a base of feasibility."
Barber's colleagues at Imperial, led by chemist James Durrant, have recently developed a catalyst from rust that carried out part of the water-splitting reaction. So far the process is not very efficient, so Durrant's team is looking at improving this by engineering the surface of the rust. "We're looking at adding small catalytic amounts of cobalt onto the surface of the iron oxide to make it more efficient."
Nocera is also working on a catalyst made from cobalt and phosphorus that can split water at room temperature. Speaking last year, when he published his preliminary results in the journal Science, he said efficient water-splitting technology would be useful as a way of storing solar energy,which is a major problem for anyone who wants to use large amounts of solar power. During the day, an artificial leaf could use sunlight to split water and, at night, the stored hydrogen would be used to make electricity as it was needed. Chemical fuels such as hydrogen can store far more energy per unit mass than even the most advanced batteries.
Both Durrant's and Nocera's catalysts are many years from becoming commercial products.
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30 Comments so far
Show AllAre you reading this people? Do you feel a [r]evolution in the works? Are we not on the cusp of a new era? A new epoch?
Praise be the Sun
I hear you but I believe our science is too clumsy to keep using the earth as a laboratory. They should move science experiments to the moon where the trashy by products don't keep poisoning us. We had a fairly well balanced ecology before the 20th century. They should resolve to keep their mitts off it until they understand it better. And no, with all the DNA knowledge, computer advances and improved microscopic imaging devices, we aren't so "far advanced" as these geeks with inflated egos claim. The fact that we know enough to be dangerous has already been amply proven.
No, not the moon!
It's too expensive, and more than that, too polluting to get out of earth's atmosphere. This space program is a waste of resources when there are so many crises to deal with down here on the ground.
We need to get the geeks into the garden, out of the cubicles and into the sun. Free the geeks!
And while we're at it, lock up white collar criminals!
Amen!
Although as a sci-fi geek I do like the space program. Get rid of the military instead :-)
Did you read the red mars, green mars, blue mars series? I thought it was great.
No, I didn't. What's it about?
Oh man, it's an adventure. It's a sci fi trilogy about a mission to mars to terraform it. The different colors (red, green, blue) have to do with the progress of terraforming from barren planet with a miniscule atmosphere to breathable with oceans. You learn a lot about Mars topography. If you like sci fi, this series is great and everything they say is plausible. They've even got "rogue" scientists that want to leave mars as it was and try to sabotage the terraforming technology.
One of the neat things about these books is that they discovered water underground in mars long before NASA did so the books are somewhat prophetic. These books are definitely NOT about a mars archetype according to Sioux Rose. I think Sioux Rose would enjoy living in the society in these books, as would I.
Moondoggy and Zmann,
Now there's a subject I love. How to get to some place away from earth so that the mad scientists can have all the fun they want without further messing up this world. It's a structural engineering problem and it can be solved with some out of the box thinking. Arthur C. Clark suggested the space elevator to get around the huge energy expense of getting to space. I suggest we build a conical tower 200 miles in diameter and 200 miles high. It would be a skeletal structure with dodecahedral trussing even though it would be gigantic. It would be festooned with wind generators for the energy to take stuff and people up and down. It would be built at the equator. At the apex, a tube structure would go out 18,000 miles (once you are above 200 miles, weight isn't a problem). At the end op the tube would be a space port and space ship construction area. This point is totally free of earth's gravity so the energy to get to the moon (or any other sphere in our planetary neighborhood) is small. All the greedy, crazy, pollution loving mining corporations could be sent to unpopulated parts of the solar system. All the dangerous experiments could be made safely away from earth. Intense solar energy would be available to pipe down to earth. Finally, if three of these conical towers were built equidistant of each other along the equater, they could be connected by a gigantic ring in space 18,000 away with a train circling it and habitats for humans as well. No it's not pie in the sky; It would be a RING around earth in the sky. Once it's done, we make internal combustion engines illegal. This immediately stabilizes the CO2 problem. Tele-Transportation and work would do the rest to give us a green planet. Zoning to require the elimination of concrete jungles and active protection of pedestrians by robotic devices would make the world safe again. I'm just dreaming here but you all are welcome to dream along too. I've got some plans for the moon, too.
AGG,
One cannot read something like what you wrote without putting it down and going on to other things for awhile to let it simmer. It's so fantastic and new (to me anyway) to just give you a knee-jerk reaction. I would rather meditate on it, sleep on it and then come back with a thoughtful response.
Well, I did that, but still need to ponder it some more. My initial reaction was mixed feelings between "sounds plausible" to "sounds completely outrageous". I want to dismiss it as just wacky, mad-science fiction and a geeks wet-dream, but on the other hand there are some intriguing ideas there.
There is a part of me that is fascinated with advancing technologies, but a bigger part of me that just longs for the innocent purity of unmolested nature. I love bird songs and the sound of water running over rocks and wind in the trees, the warmth of sunshine and puffy white clouds building in a cobalt blue sky, the laughter of children playing and the whinny of a horse, the snapping of a dragonfly's wings and the chirping of crickets.
I don't know if I like the idea of a tremendous man-made ring around the earth, but I like the idea of fast and efficient, non-polluting transport. I have some questions for you, and one is, what about storms? How would we keep this thing from going into an out of control wobble with catastrophic implications?
Oh yeah, the wobble is eliminated for by the cone shape, right. But who is going to give up a 200 miles circle of land? And equidistant implies at least one tower would need to originate in the ocean floor. And what happens when it is bombarded by space junk or a meteorite? And have you calculated how much resources and energy would go into it's development?
Why three equidistant towers? Why 18,000 miles away? Have you considered how massive this ring would be? It would be how many miles in diameter? 88,000 miles (I'll let you do the math)? Would it interfere with the magnetosphere? And many questions such as this.
In the end, I think it would be too expensive to build, it would need too many resources, and it would cause too much displacement at the foot of the towers. It would also likely cause disruptions in weather patterns and a whole host of other problems. There are many problems to be resolved here on earth for us to focus so much attention to space exploration, as much as it sounds like a fun and educational adventure.
And how do you propose the rest of your scenario? And what about the potential risk of sabotage? All technologies have their inherent risks. The further we go from relying and harmonizing with natural systems, which are self-correcting, the more we create unforeseen problems with sometimes tremendously devastating consequences (like atomic fusion).
If I were to choose a scenario for our future between replies to this article, my gut instincts tell me that "stormyweathersa" sounds sane while yours sounds outrageous. However, I am open to all ideas regardless of their merit. So please, feel free to elaborate, and while you're at it, indulge us in your "plans for the moon". Regards!
"If the leaf can do it, we can do it but even better," he said.
How arrogant. Yes we've built B747s with all the pollution associated with their construction. No flying machine we have ever built is biodegradable. No flying machine we have ever built can return to the soil and replenish it. The efficency of a dragon fly or a hummingbird or even a bumblebee is still marvelled at because WE STILL CAN'T REPLICATE IT. With my training in the biological sciences, I can attest to the hubris in scientific circles. We are so far behind nature, it's pitiful. Yet you have these salesmen scientists always talking about our great and wonderful advancementents and how we can "improve" on nature. Hey assholes, how about trying to imitate nature so you don't keep trashing the planet? Show some humility, you brain dead geeks! Or is this just hype to get more grant money?
By the way, artificial photosynthesis has been attempted since the 60s. This IS NOT NEW. The current spin just has something to do with sequestering CO2.
AGG, that was my thought too. What arrogance! We can of course try to learn from nature, and a way to start is by looking at the OVERALL effect of everything we do. It's ridiculous to assert that a 747 is somehow "better" than a bird, not showing the efficiency numbers. A bird can eat a few morsels of food or a worm here and an insect there and carry its weight while flying. It would be interesting to see how many calories are needed for a large aircraft - on a weight-for-weight basis. We should also include the energy required to manufacture this aircraft (and maybe convert it, on a life-cycle-basis, to what's required per mile). Let's also compare the pollution produced by a 747 and a bird, and see what kind of footprint they both leave - that is, how much forest area is needed to absorb the CO2, so as to remain carbon-neutral. Oh, and while we're at it, let's not forget that fossil fuels are a one-time bonanza that will run out someday. So, let's make this comparison using bio-fuel or some other renewable source of energy, all the while making sure we stay carbon-neutral - that is, no net emission of carbon in making this fuel. And then let's see if we are truly better than nature.
I had the same thoughts, and I agree with what both of you are saying. Thanks for highlighting that.
We can't improve on nature because it's already perfect. The best we can do is learn to harmonize with it, because we are not separate from it.
The worst we can do... well, we've seen plenty of examples already.
So...where does the pure water to be split into hydrogen and oxygen to fill enough of these plants covering 0.16% of the Earth's surface come from, when fresh water is already in short supply?
if the energy is cheap enough, you can get the water out of the air by the simple process of dehumidification. High quality water,too, already distilled and ready for use.
I don't think that first idea would work in the deserts mentioned in the article as ideal placing for the power plants. And the second one would require some sort of shipping, or trucking, system to keep them supplied with water...again, more and more scarce.
>> the new devices would not suck CO2 out of the atmosphere.
No, they'll be sucking scarce water out of the ground instead.
I'm glad I'm not the only one who noticed that.
I am one of those that got tremendously excited about the prospects of a so-called 'hydrogen economy', especially if the hydrogen can be produced using renewable energy and at a competitive cost. But over the last more than 15 years, it has become clear that this is no silver bullet. I still think hydrogen-based systems such as fuel cells and hydrogen as an energy storage medium in solar PV systems will find a place in the future. But to simply say "Chemical fuels such as hydrogen can store far more energy per unit mass than even the most advanced batteries" is TOTALLY misleading, because hydrogen is so light (in fact, the lightest element), it takes lots of energy to compress it or liquefy it so as to pack a decent amount of fuel within a reasonable volume. I no longer feel excited about hydrogen-powered fuel cell cars. Buses? Maybe. In the meantime, conservation in all areas of life is what's needed. And a complete re-look at making products that are completely recyclable or bio-degradable and that are non-toxic. Which means, discarding so many of the current products and technologies and starting again. And this time, with a bit of humility, and not treating the entire planet as some kind of giant trash can or landfill.
Also, the energy efficiency of the electrolyzing the water, compressing the hydrogen, the running the hydrogen through a fuel cell is much, much lower than simply charging a battery pack - which, for lithium cells, is typically beter than 90% efficient.
True. Until recent years, though, a solar PV-electrolyzer-fuel cell system looked like such a beautiful, elegant concept, if one could forget the cost. With continuing improvements on the battery technology front, it's harder to make a case for an electrolyzer/fuel cell system. Yes, why not charge the batteries directly, instead? When used as a combined power source and heating system, though, fuel cells could still play a role in certain applications - that is, if the cost if acceptable and there aren't cheaper alternatives.
Overall efficiency and life-cycle analysis, together with a look at cost and reliability - that's pretty much all the info. that we need to choose between various technologies and systems. Now, of course, we have to include the environmental implications and the sustainable nature of a technology or system, as well.
Respiration and Photosynthesis compliment each other in harmony.
The sugar produced by photosynthesis is energy in stored form. What we need to do is find a way to turn sugar into usable energy for our needs.
All this other crap like using rust, cobalt and phosphorous etc. is where we are trying to reinvent the wheel. Like synthesizing natural herbs instead of just using the real thing.
Our body burns sugar to produce energy, this is the compliment of the equation.
*******
In the end I fear we will realize the nature does it best, and we should of just let well enough alone! LIVE SIMPLY!
ZMAN is making a basic error of Assuming that you need "Pure Water" to accomplish this.
We have Entire Oceans full of salt water.
Rivers of "grey water" from sewage treatment plants.
There is no shortage of Water for this research.
Just a shortage of the Money and Researchers needed to do the work.
There are several pilot projects already running where Greenhouses are being used to, not just grow Vegetables, but also turn Wastewater and Salt Water into pure Drinking Water.
The "concept" works. They are now testing variations on the process to find the most Cost Effective ways of doing it.
Add the "Leaf" technology to this effort and get Fuel as well as Food and Water from a Greenhouse.
Thanks for correcting me. I was wondering about sea and wastewater, but then you'd need another system in place to get rid of the leftovers of the process of creating hydrogen if it's more than just oxygen.
Greenhouses are now filled industrially with CO2 to produce more vegetables in less time. I would love to know where you got your information. I am building greenhouse pods that can be placed anywhere and produce vegetables, fruits and using water much more efficiently.
Knowing how to produce drinking water out of wastewater and salt water would be very helpful. Back to the leaf again. I'm not a scientist but does anybody know if a green house large enough,hermetically sealed, and in it, mimic the parts of the leaf into large components, and bring them back together into a large leaf. just like we fly planes without flapping wings, use our science to find materials that will act similar to those identified components. Maybe growing them in isolation and then putting them together?
Just a minor point, but remember that the most plentiful element in the universe is hydrogen. Certain isotopes (deuterium, tritium) are somewhat rare and have some "interesting" nuclear applications (e.g. heavy water) but the main thing to remember is that, even though Oxygen composes about 21% of our atmosphere, we really need to husband it because we absolutely have to have it to breath. Any process that burns a hydrocarbon steals some oxygen out of the air. Burning just hydrogen steals oxygen too but the "waste" product is pure water. So you can see, if we can get the balance right, we could all benefit. People worry about water. As long as we can get oxygen, we'll be able to burn (oxidize) hydrogen and get MORE water. Earth is not the only place in the solar system with lots of oxygen in the rocks (carbonates). All this technology is messy so I would like to see it away from earth but it's certainly doable.
"But in the end we built 747s and Airbus 380s, completely different to a bird and, in fact, even better than a bird."
I don't think so.
I enjoyed very much reading the comments. I don't have a scientific background, but I decided to put my 5 cents. Nature is the best adaptation ever. All systems are designed to interact with other systems. They balance each other. Too many flies, a lizard and a bird appear to balance the equation, and so on and so forth. The exception to the rule is us. Human beings, the catalysts. We evolved into cocoon machines, always on the defensive. We build things around us to protect us. The extreme behavior would be hording and greed. We lose perspective of being in the now and seeing things for what they are. I beleive we will crack the mystery of photosynthesis. If we could start by loving and appreciating the inmense beauty of the diversity of our planet, and take the time to observe it all, we will first come into balance with the planet in a very organic and natural way(ecosytems, population, energy use et al.) We will need to reproduce less and move to a more symbiotic relationship with life. Our needs would be fewer,and have more time to be responsible creators. Art and science would merge as we practice a deeper intuitive response to our next breath.
Genetically modified (and patented) plants will probably be created for increased efficiency to produce the hydrogen. Algae is already being researched for its ability to manufacture fuel. The future it will certainly be a much different world biologically for humans to have to adapt to.
Perhaps humanity really can turn over a new leaf? Although, with a meagre one million pound grant in research money, you have to wonder exactly how committed to clean energy we actually are!
As long as it's not yet another bio-fuel creation then I'll like the progress, especially if it doesn't take food out of peoples mouths.
I'm heartily sick of the whole rudimentary 'we must burn something to power something else' concept and mentality that's been around for ages.