This week, we're investigating alternatives to petrol. We'll board a biofuel powered bus to meet scientists who are using algae to make biodiesel. And we'll find out how to turn rubbish into hydrogen, and meet the people behind Bristol's first hydrogen fuel cell powered boat!
In this episode
01:31 - Always Look on the Bright Side of Life
Always Look on the Bright Side of Life
This weekend may have brought disappointing news for English rugby fans - although well done to the Welsh - but there's always next time. Or maybe we'll win the football. For non-sports fans, this kind of optimism in the face of persistent failure seems crazy. But have you ever wondered why some people continue to look on the bright side of life - whether it's about sport or more serious life events - when it seems to an outsider that the odds are stacked against them?
To see if they can explain what's going on, Dr Tali Sharot and her team at University College London have done an interesting experiment in brain scanning, which they've published in this week's Nature Neuroscience.
The scientists persuaded 19 volunteers to lie in a machine known as an fMRI scanner (short for functional magnetic resonance imaging), which measures activity levels in different parts of the brain. Then they asked each participant to estimate the chances of 80 different unfortunate events befalling them - such as having their car stolen, or developing a serious disease like Alzheimer's. After each guess, the scientists told the person the average probability of that event happening to them.
Once each volunteer had been through the scanner, the researchers asked them to to fill in a questionnaire designed to test their levels of optimism, and have another go at estimating their chances of each event happening to them. And that's when they noticed something interesting.
It seems that the volunteers did shift their estimates of the chances of something bad happening, but only if it turned out that they had previously thought their chances were higher. So if they had thought they had a 40 per cent chance of something bad happening, and were told the risk was only 20 per cent, then they would adjust their estimate downwards. But if they thought they had a low chance of something happening, and were told the average risk was higher, they tended to ignore the data and make a smaller adjustment to their guess.
The clue to what's going on here came from the brain scans. The scientists found increased activity in the frontal lobes of the brain if the chances of a bad thing happening turned out to be lower than expected - suggesting that the person was in some way recalibrating their beliefs. But if the chances of something bad happening was actually higher than the person thought, the scientists noticed much less brain activity. And the more optimistic a person was, according to the questionnaire, the less brain activity they saw, suggesting that the person was disregarding the information and not processing it.
It's important to point out that this study only involved 19 people, so it's pretty small. And fMRI imaging studies can be notoriously difficult to interpret. But it certainly helps to shed some light on how someone's character - whether they're an optimist or a pessimist - influences how they make decisions.
On a simple level, this research helps to explain why England fans cling to our belief that we really could win every tournament we enter, whether it's rugby, football, tennis or anything else. But on a more serious note, looking on the bright side of life can be very important as a way of dealing with challenging life events, such as major illness, divorce, or being a victim of crime. But in other ways, it can be quite damaging. Mistakenly believing that your chances of a specific event happening to you are much lower than they actually are can influence behaviour - such as quitting smoking, practising safe sex or even saving for your retirement.
And financial experts are known to underestimate risks and be overly optimistic about potential profits - so maybe the subconscious reluctance of the financial world to accept the real risks of certain investments may have unwittingly led to the current financial crisis.
05:46 - Where Earth got its water
Where Earth got its water
A comet not far from Earth has shed some light on how our planet could have come by much of its water, a new study has revealed.
Writing in Nature, Paul Hartogh, who is based at Germany's Max Planck Institute for Solar System Research, used ESA's orbiting Hershel Space Observatory to study a small 1.5 kilometre-wide comet called 103P/Hartley 2, which formed originally out in the Kuiper Belt beyond the orbit of Pluto and now follows a 6.5 year elliptical orbit in the region of space between the Earth and Jupiter.
Hartogh and his colleagues probed the comet's "coma" - the pall of dust and debris thrown off by the body as it is warmed by the Sun - for the telltale-traces of water. Specifically, they were looking at the relative proportions of "heavy" hydrogen - or deuterium - that were present.
Water on Earth contains about one atom of deuterium for every 6500 atoms of "light" hydrogen. This a close match for the levels seen in asteroids and many meteorites but about half as large as the levels seen in other comets that have been measured far out in deep space in a region called the Oort cloud.
Consequently, space scientists had concluded that when the Earth first formed it was a hot, dry and barren rock that, as it cooled sufficiently for liquids to condense, was progressively wetted by the arrival of water-laden asteroids. Comets, they thought, must have been a relatively rare contributor to the planet's early water supply.
However, the observations from 103P/Hartley turn this idea on its head. The comet shows a deuterium-hydrogen fingerprint that is almost exactly the same as Earth's own water. It also reveals some interesting details about the birthplaces of the comets themselves and therefore the structure of the early solar system.
Comets like 103P/Hartley are thought to have formed in the Kuiper Belt, about 50 times further from the Sun than Earth is, and then migrated inwards later. Conversely, more distant comets like those now in the Oort Cloud and over 5000 times the Earth-Sun distance away, are thought originally to have been born near Jupiter before being gravitationally booted into the outer reaches of the solar system later.
But because these Oort Cloud comets formed closer to the Sun originally, and therefore would have been exposed to higher temperatures, they should have a lower deuterium-hydrogen ratio than their Kuiper Belt counterparts that formed under cooler conditions.
Instead the scientists have found the opposite. This argues that something is out of kilter in our understanding of the formation of the early Solar system, but it will take further cometary chemical forensics, like that announced by Hartogh, to ultimately reveal the answer...
08:58 - The Nobel Prizes 2011
The Nobel Prizes 2011
with Victoria Gill, BBC Science Correspondent
This week has seen the announcment of the 2011 Nobel Prizes, so we invited BBC science correspondent Victoria Gill to walk us through who got what, where and when, and why...
Victoria - Let's do it in the order that they were announced. It's always a fun week on the science desk when the Nobel Prizes are announced because we actually get to cover a breaking story rather than perusing all the literature and then trying to pitch science stories to all the editors. They want stuff from us so it's really exciting!
The first one, the Nobel Prize of Physiology and Medicine was shared between three researchers. Half of the (almost) million-pound prize went to Bruce Beutler and Jules Hoffman, and this whole Prize was to do with the immune system. So, what Bruce Beutler and Jules Hoffman did was figure out the gene that's responsible for your innate immune system, and that just means the gene that gets switched on so that your immune system figures out that there's a nasty microorganism, something foreign in your body, and tries to get rid of it. But there's another part in your immune system that's really important, your adaptive immune system, which you kind of might be more familiar with from being vaccinated. Kids get jabs to trigger antibodies and that's how your body adapts to be able to retain a memory of something nasty that caused an infection before, so it can get rid of it. Ralph Steinman discovered the gatekeepers to the adaptive immune system because, obviously, you don't want your body turning on some organism or cell that's already in your body that's doing no harm at all. You want it to be recognising foreign stuff that's going to cause a problem. These are called dendritic cells, and they can switch on your T-cells which are part of your adaptive immune system and create that memory. So, really remarkable stuff!
Chris - There was a controversy that raged around Ralph Steinman, wasn't there?
Victoria - There was indeed. Tragically, he died three days before the award was announced and the Nobel committee hadn't realised. There is actually a strict rule that a person who is deceased will not be considered for the Prize but they didn't know and he's been allowed to - it's a bit of a historic moment - to keep that Prize posthumously, so I think that's very fitting.
Chris - Didn't he also experiment on himself?
Victoria - Yes, he did. He died of pancreatic cancer and there's an amazing story on the BBC website about how he took research to a whole new personal level because he was actually testing pieces of his own cancer to see if he could raise an immune response to them, so really remarkable stuff.
Chris - Okay, well let's go from Earth out into space because the Physics Prize went to a clutch of scientists who were looking at the expanding universe, and we've actually interviewed a couple of them on the Naked Scientists.
Victoria - Yes, indeed. A remarkable bunch of guys and in really, really keen competition which is I think is why they managed to turn the tables on what we believed about what the universe is doing so quickly. Saul Perlmutter, Brian Schmidt, and Adam Riess shared the Nobel Prize for Physics for figuring out that the universe's expansion is not slowing down, it's actually speeding up. The interesting postscript of that is that there must be some force counteracting gravity to allow that to happen. So, it seems like a huge amount of our universe is made up by this mysterious force called Dark Energy. There's an amazing comment from the Nobel committee that said, "Now we know this, everything is possible" which I just think is a wonderful statement about just how little we know about the universe and how much more there is to find out and they've sort of opened that door.
Chris - Well let's go to chemistry because that's the 3rd Prize, isn't it? So what was given away for chemistry and to whom and for what?
Victoria - It is indeed. Dan Shechtman from the Israel Institute of Technology won the Nobel Prize for Chemistry for discovering quasicrystals and my reaction to this was, "What on Earth is a quasicrystal!?" I'm ashamed to say that as a former Chemistry World reporter, but I've been doing some reading around it and it's a really remarkable story. He basically discovered this when he looked at a very rapidly cooled metal alloy to see what the structure was. Now this shouldn't have been a crystalline structure at all; very, very rapidly cooling a liquid should just throw all of those atoms into disorder. But it was a crystal, which is not too unusual - lots of crystals form in nature, but it was very, very weird. It had this 10-fold symmetry. What he was seeing was concentric circles of 10 points, and what that meant was you couldn't really create a crystal out of what he was looking at. He actually said, "Such a creature cannot exist" because if you imagine, it'd be like trying to make spherical football out of just 6 pointed polygons. It just doesn't work. It doesn't fit together and it's taken mathematicians and even artists to figure out what these quasicrystals are and that they can form. So he really turned everything around in terms of what we thought of how matter can be structured, and he was thrown out of his research institute for that. So a really brave guy, kind of standing up for his research.
Chris - Has he got his job back?
Victoria - He's got a new job now and a Nobel Prize, so I think he'll be laughing now!
Chris - So the good guys won in the end?
Victoria - Indeed.
13:52 - Antimicrobial chemical keeps injured arteries open
Antimicrobial chemical keeps injured arteries open
Researchers have discovered a chemical signal secreted by blood cells that prevents arteries from furring up again following injury or angioplasty.
Called cathelicidin, the substance, which also has antimicrobial properties, is secreted by white blood cells called neutrophils that flock to sites of tissue injury and inflammation.
In tests on mice, University of Munich researcher Christian Weber and his colleagues found that removal of the neutrophils from circulation following an arterial injury caused vessels to become blocked by an overgrowth of tissue called neointimal material, the growth of which was triggered by the damage.
But when neutrophils were present, the researchers found, the cells clung to the injured parts of the artery and deposited cathelicidin locally. This then recruited a separate population of blood vessel-rebuilding cells called early outgrowth cells. These proliferated and secreted repair factors, reassembling the endothelial lining that paves and seals the inside surfaces of arteries. Re-establishing the endothelium in this way appears to prevent the potentially lethal neointimal overgrowth.
This means the discovery could also have implications for the process of angioplasty in which doctors use a tiny balloon to open up blocked blood vessels. Usually during this procedure a small metal cage called a stent is inserted to hold open the artery afterwards. But this can trigger inflammation, leading to neointimal overgrowth and re-stenosis, or blockage, of the artery.
To get around this problem, the latest generations of stents are impregnated with anti-proliferative drugs designed to block the growth of the neointimal tissue. But whilst they are very effective in this role, ironically 30% of patients who receive these so-called "drug-eluting stents" develop complications including the formation of blood clots inside the vessel. Doctors think this occurs because the drugs don't only block the growth of the neointimal tissue but also prevent the smooth endothelial lining being re-established. So a cathelicidin-secreting stent might be able to overcome these difficulties.
With this in mind, the team, who have presented the work in Science Translational Medicine, engineered a cathelicidin-impregnated stent that was inserted into the carotid arteries of a group of experimental mice. A second group of control animals received stents that lacked cathelicidin but were otherwise identical.
When the arteries from the two groups of animals were compared 4 weeks later, the arteries of the cathelidicin-stented mice showed significantly less narrowing.
According to the team, "although it remains to be seen whether this effect will be reproduced in humans, cathelicidin may prevent stents from causing the very problem they are supposed to treat and thus improve therapy for severe atherosclerosis."
17:15 - The ALMA Telescope, Solar Orbiter, Autistic Mice and Chivalrous Crickets.
The ALMA Telescope, Solar Orbiter, Autistic Mice and Chivalrous Crickets.
with Antonio Hales, ALMA; Matt Anderson, Harvard Medical School; Fabio Favata, European Space Agency; Migeul Nicolelis, Duke University; Rolando Rodriguez-Munoz, Exeter University
ALMA opens up to the Universe
Understanding the origins of the Universe is now within our grasp thanks to a new
radio telescope turned on this in Chile.
The Atacama Large Millimetre array, or ALMA, located high up in the Atacama desert of the Chilean Andes, is the largest, most expensive ground-based telescope ever built. With an array of 66 giant antennae, it will enable scientists to probe deep Space using wavelengths of light never observed before, to explore the early universe as ALMA's Antonio Hales explains...
"Between the radio and far infrared frequencies, lies the millimetre and submillimetre range which is where ALMA will operate. It carries information on the cold universe - cold clouds of dust and gas in which galaxies form. So ALMA will provide observations of those very first galaxies, how did they form? How the stars in those galaxies form? And how did those galaxies and those stars evolve in order to form the universe we see today?"
Scientists have created
mice with the rodent equivalent of the human condition Autism.
By adding to experimental animals, extra copies of a gene called Ube3a, which has previously been linked to Autism in humans, Harvard Medical School scientist Matt Anderson and his colleagues have been able to produce mice showing similar communication and behavioural problems to those seen in Autistic patients...
"The mice show no social interaction, have reduced speech or communication and they have increased repetitive behaviours. There's really very little used right now to improve communication and social interaction. Most of the therapies are directed towards the associated symptoms like anxiety, sleep disturbances, epilepsy. I think that this tool is going to be a great way to try to find things that will treat those core symptoms."
Journey to the Sun
The European space agency has this week agreed to lead the biggest project yet to study the behaviour of our Sun.
The 7 year
Solar Orbiter mission, due to launch in 2017, will involve the construction of a shielded probe that will orbit at 42 million kilometres from the Sun, a distance closer than any spacecraft to date and nearer even than the orbit of Mercury. Exposed to temperatures of up to 5000 degrees Celsius, the probe will provide unprecedented insight into the workings of our nearest star and how it affects the Earth. Fabio Favata from the European Space Agency...
"By doing this, we'll observe the origin or phenomena such as the coronal mass ejections or even the simple solar wind, especially more and more in an era in which we're relying more and more on high technological equipment. We're relying on satellite communication and satellite navigation and so forth. So in addition to probing some very elemental scientific questions, it will also help us to understand the influence of those mechanisms on Earth and therefore, cater for them, prevent damage and so forth."
Virtual Monkey Movements
Monkeys have been trained to
control a virtual arm on a computer using activity recorded from their brains.
The device created by Duke University's Miguel Nicolelis allowed the monkeys to move and feel objects in a virtual world controlled purely by their thoughts. Electrical signals were also sent back to their brains to distinguish the textures of the objects they were touching. The team hope to develop the technology to help paralysed patients...
"Basically, what we have done is to create the first brain-machine-brain interface that allows both electrical signals from the brain to control the movements of artificial devices and also to provide tactile feedback from these devices directly to the brain without interference from the body of the subject. This has the aim of creating a new generation of neuroprosthetic devices. A whole body robotic vest and exoskeleton that will be used to restore mobility in severely paralysed patients."
And finally, it seems chivalry isn't dead after all. Well in crickets that is.
Studying field crickets in the wild, Rolando Rodrigez-Munoz found that when mated pairs of crickets entered their burrows, males allowed their female partners to seek sanctuary first whilst they waited outside, increasing their own risk of predation and putting their own lives at risk. But as a reward, these males got to mate with the female more frequently, resulting in more offspring inheriting their genes...
"Most people are thinking that this behaviour would be more likely to happen in humans or closely related mammals, but we can see that even small insects can be seen being chivalrous with females. So it's good for both. Males get more offspring and females reduce their risk of being predated."
The findings counter previous theories that males guard in this way to stop other males mating with the females. The males are effectively trading a long life for one with greater reproductive success.
23:24 - Seeing Algal Blooms from Space - Planet Earth Online
Seeing Algal Blooms from Space - Planet Earth Online
with Peter Miller, Plymouth Marine Laboratory
Kat - Phytoplankton are the smallest organisms in the sea. These tiny little plants provide the base of the food chain for marine life and they generate energy by harvesting the power of sunlight using chlorophyll and drawing CO2 out of the atmosphere. Although they may be very small, they can still be studied from space. Planet Earth podcast presenter Sue Nelson has been speaking to Earth Observation Scientist Peter Miller from the Plymouth Marine Laboratory.
Peter - Chlorophyll and plankton are individually microscopic. However, when they are in massive numbers and concentrations they tint the water to the shade of green that we're familiar with and that is what we can detect from satellites. We can see how green the water is from space and, with algorithms, we can convert that into a measure of the chlorophyll and hence the amount of plankton in the water.
Sue - Now why do you want to know how much plankton is in the water?
Peter - Because plankton is so important for the carbon cycle and for other marine life, it is very important that we know where it is growing, how that is changing in our changing climate, if there is any migration of the plankton further north with warmer seas and if there is change in the types of plankton that is growing. It is a good measure of how healthy the ocean is.
Sue - Why use a satellite for this when you could maybe just use a research ship?
Peter - The satellites give us a wonderful coverage of the ocean, almost globally every day. So depending on the cloud cover, we can see through to the ocean and build up a picture of every part of the ocean on a daily timescale. That allows us to follow the progression of blooms, we can see the seasonal cycle, we can monitor for particular blooms that might be of interest like harmful algae.
Sue - Most algae blooms, like the one 50 miles long off the coast of Devon and Cornwall earlier this year, are both natural and benign and they are also an important food source, but can some blooms can be a problem?
Peter - It is only particularly dense blooms that can be a problem. When dense blooms decay, the bacteria can consume all of the oxygen in the water - usually in the deeper part of that ocean, so it is there that the bloom can have a significant effect on the marine life. Certain types of algae, under certain conditions, can produce toxins, poisonous substances that get released into the water. When they are consumed by shellfish, for instance, they can get concentrated and it is very bad news if humans eat those poisonous shellfish.
Sue - Can you tell purely from satellite data whether a bloom is harmful or not by its colour?
Peter - This is what we're studying under a European project called AquaMar and within that, we are trying to develop our tools for assessing particular characteristic colours that certain blooms indicate when they are harmful. We are studying the whole archive of data and we are picking out examples of blooms that were harmful and we're then trying to classify new satellite images to see if they are similar in colour to those known blooms.
Sue - What can this sort of information be used for then?
Peter - It is very important for the aquaculture industry. They need to know if harmful blooms are going to affect their fish farms or shellfish. It is important for the authorities that deal with bathing water because it may be something that they need to warn the public about when it happens. It can also be important for climate change studies. We need to know if certain kinds of harmful algae blooms are going to occur more frequently with the change in climate.
Sue - And when do you think you will be in a position to actually produce an algal bloom early warning system?
Peter - We have got prototype systems that we have worked on with the Environment Agency in the UK and we are now testing them around Europe. I should say that this work is based upon our national capability which is the NERC Earth Observation Data Acquisition and Analysis Service (NEODAAS) service that provides us with the core capability to process huge quantities of satellite images every day and very quickly so that if a bloom does happen, we can provide detailed information the same day that we get the satellite image.
Kat - That was Peter Miller from the Plymouth Marine Laboratory, talking to Sue Nelson about a possible early warning system for algal blooms.
28:27 - Biodiesel based on algae
Biodiesel based on algae
with Elena Kazamia, Jit Ern Chen and Dr. Nic Ross, Department of Plant Sciences, Cambridge University,
Emma - I'm riding on one of Cambridge's bio buses, so named because they run on 100% biodiesel. At the moment this comes from recycled cooking oil, but in the not-so-distant future, biodiesel could come from quite a different source - algae. Joining me on board are three researchers from the Department of Plant Sciences at Cambridge University: Elena Kazamia, Jit Ern Chen, and Dr. Nic Ross. They all work with algae, and they're here to tell me about its potential as a fuel source.
Elena - We're definitely running out fossil fuels, and even if we are not running out any time soon, we are definitely running out of cheap fuel, so the necessity for biofuels is increasing. Algae are a very general group of organisms - pretty much anything that lives in water and photosynthesises is algae. They can be single-celled or enormous - giant kelp for example, the big seaweed, is also technically algae. There are many reasons why we prefer to grow algae on a large scale for biodiesel production over any conventional land plant: algae do not grow on arable land so you're not competing with food production.
Emma - So how do you get from algae photosynthesising the sort of diesel that you could put into a car or into a bus?
Elena - Some algae, much like the cells in our bodies, store energy in the form of lipid. Some algal species can have up to 70% of their mass in oil, and so all you need to do is break that cell open and release the fuel molecules. You can do that either using solvents on an industrial scale or one of the things we are investigating in our laboratory is the use of enzymes to break some of the cell wall components, which then makes the extraction of the oil a lot easier.
Emma - Jit Ern, once you have extracted these oils from the algae, how do you then convert them into actual diesel?
Jit Ern - The molecule that we are actually extracting from algae are known as triacylglycerols, and you cannot actually put these molecules into an engine. They are not very friendly for internal combustion so what you have to do is to use a process called transesterification. What transesterification does is it converts triacylglycerol into molecules known as fatty acid methyl esters (FAMEs) and these molecules are structurally very similar to the diesel that you get from petroleum, and therefore they can be using car in engines with little or no modification.
Emma - Nick, is it possible to scale this up so you can produce diesel on a much more industrial scale, the scale on which it is demanded at the moment?
Nick - Algae are already grown on an industrial scale to make different types of products. In Australia, for example, they grow algae in giant ponds to get various types of antioxidants. So, you could do a similar thing - growing algae in large ponds. You could really scale up. And the size that you would want to scale up to is enormous - it would be something like 10,000 hectares as a starting size of algal ponds.
Emma - So what's standing in the way now?
Nick - The problem right now is that it is just too expensive to make diesel from algae and that is just because the costs are really quite large - building massive ponds, the costs of extraction. Even though it is a really attractive way to get energy, at the moment it costs about twice as much to make it as you can sell it for. The efficiency of the process is something like 2%. So we are looking at ways in which we could actually improve that. We are looking at ways to genetically engineer the algae to make them more efficient at the way that they capture light and then can convert that into, ultimately, the types of fuel molecules that we want.
Emma - And I understand that is something you are looking at, Jit Ern. You are actually studying the different genetic pathways algae use to produce oils and, more importantly, the right kinds of oils?
Jit Ern - Yes, the idea is that although algae do produce oils, the oils that they produce may not necessarily be the ones that we would like to put into our engines. One of the biggest problems of biofuels is that certain types of biofuels tend to freeze under low temperatures and therefore you have to do something. You can either put some sort of chemical in the fuel to make them have a lower freezing temperature or you can genetically engineer the algae so that they produce oil that is more liquid under low temperatures. And there are various other things - how much and how strongly these fuels burn are dependent on the characteristics of the few molecules, and all that can be manipulated genetically.
Emma - How would you then genetically manipulate the algae to produce large quantities of those kinds of oils?
Jit Ern - The first step is to shut down or reduce the amount of what we call secondary pathways or side-chain pathways - the alternative pathways that would take away molecules that we want to convert into biofuel and change them to something else. And you can do that in two ways - you can either improve the genes that are in the pathway you want, or you can remove the genes that are in pathways that you don't want. But obviously, we have to be really careful because these are living organisms - if you tinker too much with the internal genetics of the organism it may die, or it may start to produce something that you don't want.
Emma - Elena, how long do you think it will take until a bus like this is run on algae biodiesel?
Elena:: I think it depends on how optimistic you are. The optimists say we are ready to scale up, the pessimists say it will never happen! Another fundamental thing that stands in the way of production on a large scale is that we simply cannot replicate what we are doing in the lab outdoors. We simply do not know how the algae, as living organisms, interact with their environment. So, even though we have these amazing strains that we are developing in the lab that are genetically modified, can have very good lipid production, have fantastic efficiencies, if they then get eaten by something or if your ponds get populated by some other competing organism that contaminates it and you have to shut down your production system, that is also a very bad thing. The technology is not quite ready, the research is ongoing, but there is definitely a lot of will within the scientific community and so, I think somewhere around 10 years perhaps.
35:25 - Turning Rubbish into Hydrogen
Turning Rubbish into Hydrogen
with Dr. Mark Redwood from the University of Birmingham
In the UK, we throw away over 7 million tonnes of food every year, the majority of which goes to landfill. But thanks to recent advances in microbial biotechnology, this waste could become a valuable future source of energy in the form of biohydrogen...
Kat - Now, anyone who's had a rather whiffy bin will know that bacteria can generate gases, but how are you actually making bacteria generate hydrogen from food waste?
Mark - The first thing to say about biohydrogen from waste is that it's difficult to answer that question straight, because it is still an area of research and everybody has different ideas about the right way to do it. There are lots of different bacteria that will do it. The capacity to make hydrogen is virtually ubiquitous among the microbial world and there are really special organisms that we have singled-out which are really good for the process.
Generally, you can say it'll either work in the dark or it'll work in sunlight. So if you just take a pile of potato peelings or something, and you seal it in a container so that the air can't get in, the bacteria will begin to consume the sugars and use up the oxygen, so it'll go anaerobic. Enzymes in there called hydrogenases will switch on and then it will begin to fill that chamber with hydrogen.
In the process of doing that, it'll also make some CO2 and some organic acids. Those are what you're smelling. It's not the hydrogen that you can smell, because hydrogen itself is odourless. but those dark organisms, as they break down their carbon sources, produce a lot of things like acetic acid (vinegar) or butyric acid which is very, very smelly, but it's actually completely harmless. It's even added to some foods for extra flavour.
The other thing that you can do is take those organic acids and feed them to a second kind of bacteria. These ones live on sunlight, they are my favourites. These are the purple bacteria and what they do is use those organic acids and react them using an enzyme called nitrogenase. And if you set up the reactor just right and give it sunlight, then it will make a lot of more hydrogen.
Kat - And so, you've got this bacteria in a canister and then you're taking the things from them. How do you actually trap the hydrogen because, presumably, there may be other contaminating gases in there? Is this really good source of clean hydrogen?
Mark - Well funnily enough, it's actually one of the cleanest ways to get hydrogen. Everybody knows now that hydrogen is the fuel of the future. It's got fantastic advantages and people are looking at having to scale up the hydrogen production industry, because people are developing fuel cells left, right and centre, so they need lots of hydrogen for it. Everyone agrees that that hydrogen is going to come from natural gas to begin with, through the traditional process of steam methane reforming. The problem with that chemical process is that it generates a lot of carbon monoxide which is a contaminant in the gas and it's especially important as a contaminant if you're going to use the hydrogen in fuel cells, especially the kind that we used in experimental fuel cell cars. Whereas, as we eventually move towards biohydrogen, that problem will disappear because the gas is inherently pure. It doesn't contain carbon monoxide to begin with. The only contaminant really is CO2 and it comes out really 90% hydrogen or more in the first place, and CO2 is very easy to separate from hydrogen.
Kat - And so, what kind of waste are we talking about here. I mean just generally, I'm an avid composter so every week, my little bin of compost is collected by the council, but what kind of food waste could you use? Could it literally be anything?
Mark - It should be anything. Obviously, the more organic it is, the better. It shouldn't contain too many things like the packaging, the plastics, the tins - those won't do any good because the bacteria can't break them down. The thing to understand about composting is that what it really boils down to is allowing the natural degradation to occur, but with lots and lots of aeration; getting oxygen in there. That encourages the aerobic respiration to happen, to get all that carbon to turn into CO2 as quickly as possible. And the only useful thing that you get from composting is heat and as everyone will know, compost gets warm. You can sometimes find a cat sitting on them!
But if you take the same waste and seal it in a pot so that your air doesn't get in there, then it'll either go to make methane, or if you do under certain controlled conditions, it'll make hydrogen and organic acids. We think that, from examining the biochemistry and the stoichiometry of these reactions, if you can take that dark hydrogen reaction, use the organic acids from that to feed to purple bacteria then we should get about more than two times as much energy value as what you would get if you will let it react through normal digestion to methane. So making hydrogen will give you more energy than making methane.
Kat - So this all sounds brilliant - we can stick our bacteria and our rubbish in a pot and we'll get hydrogen out of it. How close are we to actually scaling this up? What sort of challenges have you still got to overcome before this is suitable on an industrial scale?
Mark - Well I think one of the main challenges is that the market isn't there for biohydrogen. People at the moment are much more used to liquid fuels. This is good for us in a way because the algal biofuel people are blazing the trails for us, developing solar reactors which we will then be able to use to make biohydrogen. One of the main issues is getting those reactors developed up to a level where they can be used economically and efficiently, and where they can be produced in very large quantities, very cheaply.
Kat - Where are you at? What do you think is the most exciting things that you've come up with lately in your research?
Mark - Well, it that just happens that we've just had something hot out of the lab a couple of weeks ago which is a real development. We've added 75% to photosynthetic productivity. We've had this project running with the Manchester Photon Science Institute about using one sunbeam to drive not one but two different photobioreactors containing two different kinds of organism. And the way that works is that, as we know, sunlight is composed of a whole rainbow, a whole spectrum of different wavelengths, and the purple bacteria that make hydrogen happen to like a particular part of that spectrum, whereas green organisms like the algae that make oil or spirulina that make nice health foods that you can buy in health food shops as a food supplement, prefer different parts of the spectrum. So all we need to do is find a way to separate the sunbeam into those two beams and direct each at a separate reactor and we'd be able to double the productivity that you get from a single sunbeam. We set up this project with the University of Manchester and they told us about dichroic mirrors which turn out to be absolutely perfect for the job. And so, we found that we can add 75% to the photosynthetic yield.
Kat - That sounds absolutely fantastic! That's Mark Redwood from the University of Birmingham.
43:02 - Hydrogen on the Waves - Britains 1st Fuel Cell Powered Passenger Boat
Hydrogen on the Waves - Britains 1st Fuel Cell Powered Passenger Boat
with Jas Singh, Auriga Energy; Keith Dunstan, The Bristol Packet Company
We've heard from Mark Redwood that hydrogen can be produced in one way using bacteria. There are also others. It's a very clean fuel, but how can we actually use it in practice?
One way is to feed in into a process which is called a fuel cell that can generate electricity and you then use this to drive an electric motor which is connected to a drive wheel or even a propeller. Ben Valsler has been to Bristol to meet Jas Singh who is from Auriga Energy and Keith Dunstan from the Bristol Packet boat company to hear about a project that they're launching to power boats using this new technology...
Ben - I'm standing down on the docks near Narrow Quay in Bristol, surrounded on all sides by water and boats - small pleasure boats off to the right, big industrial-looking things on the left. I'm joined by Jas Singh, the owner of Auriga Energy. Jas, what's your interest in marine technology?
Jas - I'm in here to build hydrogen powered boats and to operate them to bring zero carbon operations to water op so that we can actually help to reduce the global warming gases that are plaguing us.
Ben - Why hydrogen in particular? What are the other options and why have you gone for that one?
Jas - Hydrogen provides the most sustainable clean fuel around because hydrogen is the most abundant element in the universe, and when operated through a fuel cell system, which is a highly efficient electrical generation system, the output exhaust is pure water. So, it is the most emission free energy generation system that you can imagine.
Ben - So, just take me through the fuel cell itself. How does that actually work?
Jas - A fuel cell is a reverse electrolysis in that, if you remember from your school days, if you put electrodes in a beaker of water, you can break up the water into its consistent parts of hydrogen and oxygen. In a fuel cell, you bring hydrogen and oxygen together with a catalyst and you recreate water as the exhaust, and you liberate some electrons and produce lots of electricity. And then we can use electricity to power whatever we need. In this case, lights and motors.
Ben - So the hydrogen that you're using as a fuel, where does that actually come from?
Jas - Hydrogen at the moment is a by-product of a lot of the chemical industries, and in essence, if we didn't use it for fuel cell systems, it would be flared off or just wasted. And in future, and also happening at present is that we will generate hydrogen from renewable resources and therefore, hydrogen will be a totally green fuel.
Ben - But how else do you make hydrogen?
Jas - Hydrogen can be made by storing energy from wind power, from solar, from wave, tidal, and in addition, the one that is my favourite is recycling waste because we generate waste and we're recycling it. There was a study done in London by the London Hydrogen Partnership that if they use the energy generated from the waste recycling program that they've got in place, they could manufacture enough hydrogen to run the entire bus fleet in London, and London has 10,000 buses intensely used. So that is one of the many ways forward and, waste recycling through various anaerobic digestion systems kills two birds with one stone.
Ben - And how do you actually store the hydrogen on the boat?
Jas - Hydrogen is stored in a filament wound tank, a purpose-built tank of compressed gas. In the future, there is research going on around the world to encapsulate hydrogen in porous metals in essence which will be more efficient in volume terms. So that's the direction the world is heading in. At the moment, it's in compressed gas at 350 bar.
Ben - Keith Dunstan, you run the Bristol Packet boat company here and you're helping to design this hydrogen powered boat. At the moment, what is it that boats actually run on?
Keith - Well all boats run on diesel. The whole marine industry runs on diesel and it's one of the highest producers of carbon, more than aviation or any other industry. Ships going around the world are hugely polluting and we run diesel boats all around the docks here and hopefully, one day, we'll be running them on hydrogen which should be a lot cleaner, more efficient, and cheaper. Hopefully, that's the only way it's going to really happen when people start realising that diesel is going to get more and more expensive, and eventually will run out and we'll need something else.
Ben - So, can you just strap a hydrogen fuel cell and a big tank full of hydrogen onto an existing boat or do we need to do a bit more in order to integrate this?
Keith - Well you could do that, but I don't think you get anyone to allow you to carry passengers! I think you've got to get a little bit more serious about the regulations and how you can do it safely. And that's what we're trying to prove at the moment - how you can do it safely. When we first went to the marine coastguard agency and said we're going to build a hydrogen fuel cell boat they said, "What? What is that? We haven't got any regulations. We know nothing about it. It would probably take five years before we actually allow you to build this thing." Since then we've been in touch with various ministers and who have put a bit of pressure on the MCA, and within six months, they came up with some regulations. They actually just decided to use the German regulations - as long as we comply with the German regulations, we can build a passenger boat now, carrying any number of passengers.
Ben - So obviously, there's been lots of legal red tape to go through. What about the engineering challenges? How have you actually built the new boat?
Keith - It's a pretty standard boat. It's just that it's fairly sleek. We're not using a huge amount of power on this boat. We're up to 10 horsepower so the boat has got to be fairly lightly built. It's got to be robust, strong enough to withstand being knocked around the docks here. We've also got to bulkhead off the various elements of this thing. We've got a fuel tank and we've got the fuel cells, and we don't want the two to be in any way connected - We don't want sparks in either of those areas! There's three compartments you need in any of these systems. You need a compartment for your fuel cells, a compartment for the fuel tank, and a compartment for your electric motors and batteries, and all the things that spark.
Ben - Jas, we've just mentioned a 10-horsepower engine. That doesn't sound like a lot. How much energy can you get from a fuel cell?
Jas - Fuel cells can produce almost infinite energy and that they're scalable to whatever size you want. At this moment in time, there are buses running throughout the world. In London for example, there are five buses running which have over 100 kilowatts of power onboard. In the future, we see even bigger fuel cell systems. Big corporations such as Siemens are working on megawatt size fuel cell systems, which will be available to provide stationary power to big plants.
Ben - And Keith, coming back to you, how does this compare to an engine that you would see in one of these boats around us. Again, 10 horsepower doesn't sound like a lot of power. Is that enough?
Keith - I think it will be enough. We're told by a lot of people who are very experienced in electric motors and steam engines, it's very comparable. When you say 10 horsepower for diesel engine, you need to get to maximum revs before you get that 10 horsepower - 10 horsepower in an electric motor is there right from the beginning the torque, right from your very first revolution, is 10 horsepower, so it's absolutely there. I think we probably have enough. Anyway, if we don't, we'll add some more fuel cells!
Ben - And what's the long term plan? Jas, coming back to you, clearly, this is a bit of a pilot study and now, you're finally going to get something on the water. Where do you take it from there?
Jas - This is a pathway project to clear all the blockages to introduce this as a permanent installation. So where we take it is that once we've done our demonstration, cleared all the pathways, we then want to generate the hydrogen locally and introduce fuel cell hydrogen operations throughout the Bristol harbour area and reduce the CO2 output.
Chris - That was Jas Singh from Auriga Energy and before him, Keith Dunstan from the Bristol Packet Company, and in partnership with the Engineering and Physical Sciences Research Council, that company, Auriga are teaming up with universities across the country to research better ways to make store and use hydrogen. So we could be seeing hydrogen transport popping up nationwide before too long.
How does biohydrogen compare with other gas options?
Mark - Those routes to making methane are actually really good ideas and as we know, all of the waste treatment plants have been making biogas by that method for many years. One of the newer ideas is to culture biofuels or bioenergy crops or even algae, feed them into a digester and make methane. The thing about hydrogen is firstly that you have a carbon-free economy, but also that when you look at the biochemistry and the energy pathways involved, instead of making those algae and then turning them into methane, if you can make hydrogen directly, that'll be more efficient, and you'll effectively get more energy from a certain amount of land which is gathering a certain amount of sunlight.
How do we develop a hydrogen distribution network?
Mark - Well absolutely. It's a chicken and egg dilemma and it's well recognised. The way that it's being addressed is that you're starting off with nuclei, foci of hydrogen production and from there businesses will get their fleets running off hydrogen. And those will grow from nuclei and eventually be connected. And there are hydrogen highways - the famous one is in California and there are some coming up in Germany now. I've forgotten the numbers but Germany already has quite a lot of hydrogen filling stations and if you look at what they've got planned for the next 10 years, they're really serious about moving on to a hydrogen transport system.
Is a hydrogen-based infrastructure expensive?
Mark - Well it's a little bit of both, but I think it's more market forces than anything else. About 5 years ago, I think the first proper hydrogen fuel cell car was technically launched and they were about $1 million each. But just now, Toyota are selling them for just over $100,000 each. So, in a few years it's gone down 10-fold in price. We've only got to stick with it. The fuel cell market is absolutely sky rocketing and it's those fuel cells which are the key element in hydrogen powered car. What the fuel cell does is it takes the hydrogen, usually stored in a compressed cylinder, and really efficiently turns it into electricity which then drives the electric motor. The fuel cell is around twice as efficient as a combustion engine, so you could have a hydrogen powered car using a combustion engine that just burns the hydrogen, but it's much better to use a fuel cell. Of course, this is very new technology.
Are home-brew kits for energy a practical proposition?
Mark - Home energy generation is definitely a big thing that has got to come in in the future, because the more that you generate locally, the less transport is involved of resources, and then that means the more efficient the system is going to be. When it comes to a system like the kind that I study, where we're looking at turning organic wastes into energy, then a home scale doesn't really work. If you look at the amount of organic waste that each home produces, even if you were to invent the most amazing system that could get all of the energy out of that waste, it's no way near enough to provide the family with its needs. So, you would actually have to be bringing in crops from around the local fields! You'd have to have at least a community level or maybe a block level plant and I think that these minimum scale limitations apply to most of the technologies. One of the best things going on at the moment is you can get your domestic wind or your domestic photovoltaic tiles on the roof of your house, those are working very well. You can get some good schemes going on at the moment and actually make money out of those.
Can algae or bacteria bioreactors be contaminated?
Mark - If we're talking about the photobioreactors that I'm thinking of, the ones that use sunlight and purple bacteria, those systems have been tested outdoors in sunlight and run for very long periods. Simply because they're natural species they're robust - they're not special genetically engineered ones that require careful conditions - the conditions in the reactor suit that kind of organism, and the metabolism that they live by produces hydrogen. So there's no reason for anything to take over and it's unlikely to happen. It's certainly true that it's an issue in algal oil production, especially when you're thinking about open ponds which are open to the atmosphere where anything can blow in. That research field has to prove that their culture is going to remain pure enough and stable enough - they've been doing it for many years and it's looking very promising.
How safe is hydrogen as a fuel?
Mark - This is obviously a very often asked question. The people who have looked at it really thoroughly conclude that it's about the same, if anything possibly a little bit safer, with the hydrogen. As we know, hydrogen is easier to ignite than petrol - but the thing is if you have a hydrogen leak, the hydrogen diffuses away so quickly that the hazard is very temporary. Conversely, if you have a leak of petrol, it's just going to sit there until someone cleans it up, and when it sets on fire, you have a fire blanket that covers everything and engulfs the car. Look up Michael Swain on the internet - there's a really nice comparison of a normal petrol car on fire and hydrogen car on fire, and you'll see that by the time the hydrogen is burned away, the car looks very much the same, whereas we've all seen on action films (or even in the street depending on where you live!) a burning normal car is very much not a car at the end of it.
59:24 - Can we use human excrement for fuel?
Can we use human excrement for fuel?
We put this to Dr. Piers Clark, Commercial Director at Thames Water...
Piers - In Thames Water, we've made energy from poo for many, many decades now and we do it through a process called anaerobic digestion. Anaerobic digestion is a process that's very similar to what happens inside your stomach actually when you eat food. It also happens when we ferment berries to make beer. It's basically the gradual breakdown of organic matter through a natural process and the molecules that make up the food that we eat and that ultimately come out as poo gradually get broken down into a form of a gas and the gas is called biogas. It's a mixture of methane and carbon dioxide. And carbon dioxide is naturally in the air and methane is the gas that people most readily associate with being the gas that you burn on your cookers at home. We run this natural process and have done so for many years. We produce about 15 million pounds worth of energy every year which equates to about 15% of our total energy usage in Thames Water.