Turning the Tide on Hydro Power

Marine renewable technologies were comparable to those of wind in the 90s, but is the flow reversing?
01 June 2022
Presented by Chris Smith, Harrison Lewis
Production by Harrison Lewis.


A breaking wave on the ocean


The UK harbours the leading expertise in marine renewables, but water itself remains to be a major contributor to the race for net zero. Why are these technologies lagging behind the other more favourable renewable sources and what does the next decade have in store? In the news this week: a novel approach at identifying and engineering antibiotics, the Mars probe being forced into retirement and an insight into why teenage girls are more likely to suffer from depression than their male peers...

In this episode

Bacteria floating on black background

01:06 - Novel antibiotic discovered using computers

The compound is thought to disrupt the activity of infectious bacteria in a completely new way

Novel antibiotic discovered using computers
Sean Brady, Rockefeller University

It's been dubbed the antibiotic apocalypse. Microbes are becoming progressively more resistant and we're running out of drugs to treat certain infections. At the same time, most of the major pharmaceutical players have exited the antibiotic game because they just can't make enough money. Why? Because if they do come up with a blockbuster drug, then the first thing doctors will do is put it on the shelf and not use it except when they're desperate. Luckily there are still a lot of exciting developments happening at grassroots levels in universities and in startups around the world. And this week, researchers at the Rockefeller university in New York unveiled a new drug that they've discovered that works in an entirely new way to knock out common important bugs that we encounter in the clinic. Sean Brady and his team used computers to trawl through the genetic codes of 10,000 different bacteria from the environment, looking for genes bearing the hallmarks of being the recipe for an antibiotic. Chris Smith found out how they decoded what molecules these genes would make and how they produced them...

Sean - Many of our antibiotics in use today are coming near their end, due to the development of antibiotic resistance. So where do you look for antibiotics? Well, historically, many of our antibiotics have come from bacteria. But what happened is we began to run out of those. The obvious places to go look for new bacteria and interesting antibiotics from bacteria began to run dry maybe 20, 30, 40 years ago. What people have learned over that time period is that maybe we've missed a lot of the antibiotics out there. That hidden within bacteria maybe there are genes, or groups of genes, that might make new antibiotics that would help us revitalize the pipeline for antibiotic discovery.

Chris - One obvious question that springs to mind is, why are microorganisms - bacteria - making antibiotics in the first place?

Sean - That's a good question, right? We don't really know, but a prevailing hypothesis is that they're competing with each other. That they're out in nature competing for limited amounts of food. They can't talk, they can't move very well. And so how do they communicate? How do they keep others away from them? They use antibiotics.

Chris - And I suppose the ones that we focused our attentions on hither to have been the ones that we could spot, we could grow, we could study. And there must therefore be enormous numbers that we've completely missed.

Sean - That's actually what my research group worked on for the past 15 years is this idea that there are many bacteria out in the environment that we haven't been able to bring into the lab because scientists just aren't smart enough to grow them. And so you need to come up with ways in which you could identify the antibiotics they make. One way we worked on this was instead of growing bacteria, we just extracted their DNA, literally extracted DNA from dirt, and then put that into bacteria that do grow. And we've had a tremendous amount of success looking for antibiotics using that strategy. But there's one problem that came up and that was as we clone these genes from the environment, many of them never turn on, which means we can't identify the molecules that those genes should be making.

Chris - Obvious question though, Sean, when you just grab some DNA out of a hunk of soil, how do you know which bits of DNA might be promising candidates for making antibiotic molecules in the first place, so you know to focus your attention on those genes at all?

Sean - Bacteria are smart, but they aren't that smart at the end of the day, and that they've only evolved few dozen ways of making molecules. And that means we can limit our focus to just a small number of gene types. Now they use those gene types to make many, many different molecules, but evolution has only led them down a certain number of pathways. We can quickly filter out lots of the other genes that we know aren't making molecules or antibiotics.

Chris - So you have in your hands, the ability to spot genes that look promising because they've got that sort of hallmark characteristic about them that smells like this could make antibiotics. The problem has been, you can't make the genes turn on. So how have you solved it?

Sean - For a number of years, we've been working on this idea instead of using biology, we would use bioinformatics. So use computer algorithms to look at the genes and predict what they might actually make. Then once we have a predicted structure, we can use synthetic chemistry to actually make that structure. And we identified one that would kill drug-resistant, antibiotic-resistant bacterial pathogens.

Chris - And how good is it as an antibiotic? I mean, before we start talking about whether it'd even work in an animal like us. If you put this on bacteria growing in culture dishes, what sorts of bacteria can it knock out and how good is it?

Sean - It kills a number of pathogens. Staph aureus are one of the famous ones that your audience may have heard of as well as some other bacterial pathogens. And it kills them in a unique way, binds up or takes away building blocks that no antibiotic had taken away before. And it's the new mechanism that is really interesting in addition to just its activity,

Chris - You're saying, in some way, it robs the bacteria of resources so they can't grow properly?

Sean - Exactly. And it does so binding actually two molecules at once. So it's taking two resources at once. Turns out the bacteria, if you just take one resource away, can generally get around that. They eventually develop resistance pretty easily. But if you take away two resources, it presents it an often insurmountable or very difficult to surmount problem. We think that's one of the neat things about this antibiotic and it makes it very difficult for bacteria to circumvent that antibiotic. So no bacterial pathogens that have been found in the clinic that we've tested are resistant to this molecule that we've identified so far. And then when you just test in the lab where you let bacteria grow for long periods of time, they don't develop resistance to this antibiotic.

Chris - In the past, we've found some similarly very exciting potential antibiotics. The problem is when you put them near us, they're awful for us. Have you tested this compound to see if it's tolerable by living things like us?

Sean - So far it's only been tested in mice. We don't see any negative impact. It's not toxic to cells in the lab. And so far in the animal studies we've done, we don't see toxicity to the animals, which is exciting.

Harry - Sean Brady. And he's just published that study in the journal Science.

Carrots in a wooden crate

07:31 - Gene-edited food laws altered in UK

Following Brexit, the UK has changed its stance on the precision breeding of food to boost produce

Gene-edited food laws altered in UK
Gideon Henderson, DEFRA

This week, the UK government began the process of bringing gene-edited food into law. And that will allow for the sale of crops that have had improvements made to them by science. The new genetic technology bill, as it's called, will replace an existing EU moratorium on growing food that had been modified in this way and it will allow scientists to use tools like the gene editing system known as CRISPR to improve their crop yields, build in disease resistance, or even give plants added nutritional benefits. Now critics on the other hand are calling the bill GM crops, but with better PR. Although the government was intending to follow this course of action anyway, it was the looming food security crisis that led to the bill being expedited. James Tytko spoke with Gideon Henderson, who's the chief scientific advisor to DEFRA, that's the Department for Environment, Food and Rural Affairs....

Gideon - I think there are a couple of important things that have changed. One of which is that the public have got much more used to people talking about genetic information. It's quite a long time now of course, since the 1990s, and in that time we've seen really substantial benefits to human health and use of genetic information in biomedical processes. There was also quite a genuine concern in the 1990s of how this was actually playing into the hands of big business rather than helping food producers or helping the public. And I think this time around things are very different in that gene editing is a very accessible tool, which smaller businesses can use, and it's much easier to get into that market.

James - This new bill obviously has a degree of urgency with the food security issues, but does it feel also like the right time to be pushing this legislation forward when trust in scientists is perhaps at a bit of a high?

Gideon - I don't think it hurts at all that scientists have been so useful to the public in the last couple of years, but that doesn't explain the timing. The timing is more explained by the combination of the development of the tools that enable this precision breeding and this accurate gene editing, and also the UK leaving the EU so that we're now able to reexamine the regulation ourselves independently.

James - What benefits can we expect to see once this passes?

Gideon - Many other countries have been enabling gene editing of crops for some time now, so perhaps the most immediate change that we might see as consumers in this country is that products that have beneficial qualities for us as humans, or for the way that they're grown, on our shelves as a consequence of what's happened elsewhere. But even more exciting from a UK perspective, and in the only slightly longer term, I think we're going to see new crops developed, which will provide significant benefits to the environment and significant benefits to human health through their consumption, and increase productivity of our land so that we might free up some land area.

James - The bill also will enable the development of precision-bred animals as well. Can you tell me a bit about that and when we might see that come into practice?

Gideon - Well, as a nice example, is there's a porcine respiratory disease, which is endemic in this country and in many other countries, which causes a great deal of suffering for animals and dramatically lowers productivity of pig farming. And it's been demonstrated by UK scientists that we can develop a breed of pig that is resistant to that respiratory disease and that will be an early win by which we can both increase productivity and decrease animal suffering.

James - Currently, no UK supermarket is willing to say it will stock gene-edited food. New Scientist contacted eleven of the UK's biggest supermarkets, none responded to confirm. So clearly they're being very cautious; there's still a hangover from the GM crops debate. You'd have thought bringing down the cost of food would only serve their interests, really?

Gideon - Retailers are, as you suggest, fairly positive and supportive of the ability to make better, healthier food with less environmental consequence. It does make sense that an individual retailer might be resistant to come out and support as a single entity. But I don't have the sense that any retailer is hostile to these changes either. They're just not willing to be the first one to put their head above the parapet.

James - There could be other benefits of this in the long-term. I'm thinking about opportunities for countries in the developing world, for example, where some of the main exports of food crops, they might be able to grow plants that have a longer shelf life or produce a bigger yield, which before had the stumbling block of not fitting our regulations.

Gideon - Certainly many areas will be under significant heat stress and sometimes water stress in the future as climate changes, and building crops that are more resilient will be much easier using gene editing approaches than relying only on more traditional breeding approaches. So we can help to really secure food supply across the world. And one example that I like here is rice blight, which is a disease that can significantly lower the output and the productivity of rice crops around the world. And of course we don't grow rice in the UK, but it's really important in Southeast Asia and in Sub-Saharan Africa, particularly west Africa where rice blight can significantly damage productivity. There are proven gene editing approaches by which we might make rice resistant to rice blight and therefore be able to eradicate some of those problems or much improve them.

Astronauts need faster spacecraft, better radiation protection and heat shields before they can enjoy the Martian landscape in person.

13:55 - InSight probe winding down activity

This Mars lander is encountering difficulties when taking measurements on the red planet.

InSight probe winding down activity
Dave Rothery, Open University

In other news, a sad moment is on the Martian horizon for the probe, InSight, its retirement looming. You can see from the lander’s own sad selfies that dust has accumulated over the solar panels, now only capable of generating a tenth of the power it did when it first touched down. For the rest of the summer, NASA will be using the remaining juice for just 12 hours a day, which will then drop down to 12 hours every other day before the power plus is metaphorically ripped out prior to the end of the calendar year. Dave Rothery from the Open University tells Harry Lewis what it’s all been for…

David - Insight is the NASA lander Mars that doesn't have a rover. It's just a static lander and it deployed, in particular, a sizmometer. It landed on the surface and, with its arm, it took its sizmometer out and placed it firmly into the ground and covered it with a lid to keep the wind off it. This sizmometer is sensitive to the vibrations in the ground caused by Mars-quakes. It's our way of listening to what's going on inside Mars.

Harry - And what has it been able to find?

David- Well, first of all, it's told us that Mars is seismically active. There are Mars-quakes. The biggest one, magnitude five on the famous Richter scale, happened only two or three weeks ago. We're able to use the wave vibrations that travel through the body of Mars, different types of vibrations, compressional waves and shaking waves, and look at the polarization of the waves as well. You can work out the layered structure of Mars, so we've detected that Mars does have a core for the first time. It's not a surprise, we expected it to have an iron core. It's a bit bigger than we expected, the crust of Mars is a little bit thinner than we expected - then there's a mantle in between. So, we've got the internal structure of Mars constrained and we think part of the core is probably fluid as well.

David - There's an experiment on board that measures the exact rotation of Mars, and how that varies on a fairly short time scale shows that Mars is a little bit sloppy inside. So, we've got hints of the core being fluid as well. If we're honest, we don't understand the early stages of planetary formation - when does for core separate from the rocky part and how thick the various layers are? What is going on inside a body? Why do we still have earthquakes on the earth? We know we 've got plates moving around as well as erosion and deposition changing the loading on the crust so things are creaking all the time. We don't have plates moving around on Mars, but we do have erosion and deposition, so the load on the crust is changing. But how does it respond to these changing forces? Insight has told us a lot about the inside of the planet and this hasn't been done before. The only body where a working size monitor has been deployed previously is onto the moon by Apollo astronauts who left four working sizmometers on the moon at the end of the Apollo program, but we've never had a sizmometer on any other planet. We've had one on Mars for three and a half years now.

Harry-  Other probes that are out there on Mars, I'm not sure how many there are, are they facing similar issues or is this something that is quite specific to Insight?

David- There are three rovers working on Mars at the moment, there's a Chinese one, which has been there several months now. We don't hear much of that. NASA has Curiosity, which I think has been going for a decade or more, and there's Perseverance, which landed early in 2021. That's just about to trundle up towards the top of the delta where it landed. So, we have rovers moving around Mars and because they're moving they don't get solar panels covered with dust and a lot of the power comes from radio thermal generators anyway, they've got plutonium on board to generate electricity from that process. They're not dependent on sunlight for power.

Harry- Where are we up to in Mars exploration? What are we expecting to happen in the near future?

David- Well, the big disappointment this year is for the Rosalind Franklin Rover, the European space agency lander on Mars, which now isn't going. This is because it was going to be launched on a Soyuz-Fregat launch vehicle from Kourou in French Guyana, and indeed the descent and landing system is Russian as well. The whole Ukraine situation means that that mission is not now going ahead. It would be great to have Europe's own Rover trundling around on Mars as well. I have a lot of colleagues who work very hard on defining the landing site and all their careers are on hold now. But, that aside, we are getting samples collected by NASA's Perseverance rover, which eventually will come back to earth through a joint NASA - European Space Agency project to bring samples of Mars back for analysis.

Harry- And that's a crazy thought that we'll soon have something that's so far away within reaching distance.

David- It'll be great to have samples from Mars that we've collected ourselves. We do have bits of Mars already because there are meteorites, chunks of rock that have been knocked out of Mars by impact, and then have gone through space and fallen down to earth and been recognized. So, we do have some out of context Mars samples, but we have nothing that we've collected ourselves.

A depressed woman

19:39 - Psychiatric problems in adolescence

The way boys' and girls' brains develop at different rates may affect their risk of developing depression

Psychiatric problems in adolescence
Lena Dorfschmidt, University of Cambridge

As we go into our teenage years, all kinds of changes happen to our bodies and our appearance. But there are also important changes happening to our psychology too, and sometimes that can lead to mood disorders like depression. What's striking though is that girls seem to be affected twice as often as boys. But why? Well Lena Dorfschmidt, at the University of Cambridge, wondered the same thing, so she scanned the brains of a large group of adolescent children to look at which areas change their patterns of connections the most at this age. In girls there was a lot more rewiring going on, particularly in brain circuitry known to be linked to depression. This, she suspects, might make girls more susceptible to developing a mood disorder in the first place…

Lena - We know that, during adolescence, our brains develop very rapidly. We also know that, during that time, a lot of psychiatric disorders are diagnosed. For example, depression. Women are much more likely, about twice as likely, to be diagnosed with depression than men. We asked ourselves the question, "is there something about development during adolescence that may trigger this increase of incidence of depression in women during that time?"

Chris - You don't just think that there's a disparity in pickup; that women are more likely to talk about it, men are more likely to do the stiff upper lip thing and keep quiet.

Lena - There may be a certain component of that. I don't think that explains everything, though. I don't think we have women reporting symptoms twice as much as men do. Also, we have a separate sample of data where we can actually see that, even in healthy adolescents, women are more likely to experience difficulties with mood.

Chris - And you are attributing that to these very rapid changes that have to happen to the brain as we grow up?

Lena - Yeah, exactly. You can imagine this: if you wanted to reorganise your room and move things around, there's a chance you might drop something on the way. The more you change, the more likely you're going to break something. A brain is in some way similar. If you remodel or rewire a lot of connections in your brain, there's a greater chance that things may go wrong along the way.

Chris - This is the moving parts get broken more often hypothesis, isn't it?

Lena - Yeah, exactly.

Chris - So how did you try and get underneath the skin of that then?

Lena - We used MRI scanners where we can take 3D images of the brain and monitor brain activity while people are just lying in the scanner. We know that even when people don't do anything while they're lying in the scanner, we can find out a lot about the way that their brain functions already.

Chris - So, you've got groups of adolescents that you can watch in this way and ask the question, "Well, how is your brain wired up?"

Lena - Exactly. We just look at how the different brain regions communicate with each other. If neurons in specific regions fire together, we say that they're very likely to be connected, or there's connectivity between these regions. There may be two regions that are highly connected, they fire together all the time. We think that they are working together.

Chris - And how do you map that onto underlying mood or psychiatric problems?

Lena - What we did first is we looked at what this firing together of brain regions looks like in males and females separately, and then constructed a map of differences between them. We can now understand which brain regions are most different between girls and boys and men and women. What we found is there's a set of brain regions where the females develop much more drastically than the males do. So, in those regions, the women restructure, rewire much more than boys do. Then, we looked at these regions and overlapped them with the regions that we already know from other studies are implicated in depression. There's a really good match between those. We know that the same regions are impacted.

Chris - Why would a female brain wire itself into a state of depression at all?

Lena - I don't think we can say the female brain wires itself into the state of depression. The people we looked at are healthy adolescents. The only thing we are trying to show is that male and female brains develop differently and women change a bit more. It is simply that because they change more, we could assume that something may go wrong.

Chris - So, you've now got this map, or this network of connections between different regions of the brain. And you can see dynamically how that changes in adolescence. It strongly overlaps with areas that are implicated in subsequent mood disorders. Does this give us any insights into what causes that to happen? When people do get mood disorders, what we could do perhaps to head it off before they end up with an entrenched depression?

Lena - Unfortunately, we don't understand very much about that yet. There isn't a great amount of detail on how depression looks different in men and women. And this is really what we're trying to do with our work here. We're trying to show that if we want to understand how to treat depression, we need to look into males and females separately because we can now already see that there is a signal that is very different between them.


25:59 - Generating electricity from water

Which marine renewable technologies are out there...

Generating electricity from water
Simon Waldman, University of Hull

Now, last week, solar power was in the spotlight, but we've waved that goodbye, and this week it is the turn of tidal energy to be subject to our scrutiny. We're going to see how marine renewable technologies can contribute. The UK makes for a great case study, of course, because being an island nation, there's no shortage of water all around us just waiting to be farmed. Oh boy, it looks like Harry has nipped out of the studio. Where's he got to?

Harry - I'm down in Milford on Sea, it's on the South coast of the United Kingdom. On a day like today, when it's sunny, it almost looks like the Isle of Wight is within spitting district. We have an estimated 18,000 kilometres of coastline, and, on top of that, territorial waters that stretch 22 kilometres out to sea. It seems almost nonsensical that we are not making the most of this marine environment, this resource as an energy source that's on our doorstep. With that in mind, I'm hoping that we're going to be able to find out why we don't have the technology in the marine environment to compete against something like wind in the UK. And, also, what the future of marine renewables looks like.

Chris - So how do we currently extract energy from water. Well, Simon Wardman is a lecturer in renewable energy at the University of Hull.

Simon - Last year, 43% of the UK's electricity came from renewable energy. About 30% of that was offshore wind about a quarter of it was onshore wind. And then there's some solar and some hydro and some other things.

Harry - That's got to be better than expected, isn't it? That's got to be breaking the targets that we've set?

Simon - Well, we're hoping that by 2050 we'll be entirely zero carbon, which means renewables plus nuclear. So, we're not quite there yet, but we're doing well at it. And that's up considerably, it was only 37% in 2019. Back in 2010, it was 5%. So, it's been a remarkable shift in that time.

Harry - Wow. I didn't realise that. How do we go about generating electricity from bodies of water? What are the different methods?

Simon - Hydro, at present, is about 5% of our renewable electricity generation. That's significant. The other two big ones, potentially, are tidal energy and wave power. Tidal is working. There are early machines in the North of Scotland that are generating onto the grid right now. So, a tiny fraction of what goes into the lights that you and I are sitting under is coming from the tides. There was a recent scientific publication that estimated that, if we develop it, we could get about 10% of the country's current electricity needs just from tidal stream energy. Wave is not at that stage yet. Wave is still very experimental and is a bit further off.

Harry - Hydroelectricity in the UK is really running at full capacity, leaving us with three marine environments left to exploit on a major scale. As Simon said, that's wave energy, and we can actually split tidal energy into two different factions: stream and range. After much deliberation, I think the best way of demonstrating how these three potentially big players can work is to run a bath. That should probably do it. Let's turn of the taps. Ok, so, first up we've got wave energy. That's going to require a little bit of chop.

Harry - There are a few ways that we can make the most out of this environment and take energy from it. But the most effective method so far has been to place a long line of cylinders on the surface right here. That's been demonstrated by a massive, 120 metre prototype called Pelamis off the shores of Portugal. The name is actually derived from a sea snake, so it sort of looks like one of those toy snakes that can move, or a toy train with all its carriages. As the cylinders bob up and down, two hydraulic rams on either side are pulled and pushed alternatively, and that in turn drives a turbine. In the other two cases, we're drawing on energy from the tide. Let's start by trying to make a large swell in the bath, back and forth. Here we go. If we want to exploit the large tidal ranges we have in the UK, we need to wait until the tide is in and then try and trap it somehow, try and trap some of that water. I'm going to use a storage lid, but it's more likely companies would build a damn like structure or wall.

Harry - Here we go. Let's try and get some then. All right, it's not a great seal, but I think I've got some. What you can do is you store it, and then eventually when you'd like to, and when the tide is out, you can release this energy which will in turn drive turbines much like a hydroelectric down. So, all that energy is stored up and we just release it. Finally, we have tidal stream renewables. Now, the currents that are produced by the swell of the tide are scarily strong, so if we could place a simple device in the water capable of surviving these extreme conditions, it could be relatively simple to drive a turbine. For this, obviously our device would need to sit under the surface of the water.

Simon - At the moment, we are favouring tidal stream, mostly because tidal range is very tempting in terms of the amount of power that's available, but it has very large environmental impacts and has a very high upfront cost. Whereas, tidal stream is a bit easier to get into.

Harry - We're still at the start of testing these prototypes. Why is it that we are stuck in the Stone Ages - maybe that's a bit harsh - of marine renewables.

Simon - I think it is a bit harsh to say we're stuck in the Stone Ages. Some people would say that, at the moment, tide is in a similar place to where wind energy was in maybe the 1990s. In the last decade, the industry has demonstrated that tidal energy works. The task now is to deploy it at greater scale, to learn by doing, and bring the costs down.

Harry - You said that this could make up 10% of the UK's electricity needs. Whereabouts would these machines be employed?
Simon - For tidal stream, you have to put the machines where the fast flows are. In the UK, that means various places around the North and the West of Scotland, also around Anglesey, and some of the West Wales headlands, and possibly some other sites like the south coast of the Isle of Wight.

Harry - If you haven't got wind and you haven't got any sunshine, you know you're going to have a consistent source of energy.

Simon - Exactly. Tide isn't available all the time, but we know when it will be available. Because the wind doesn't blow all the time and the sun doesn't shine all the time, we don't want all our eggs in one basket. We want to have a range of technologies to help us out.

Harry - In terms of bodies that we actually have in the water, what do we actually have that's generating electricity around the UK coastline.

Simon - There are quite a number of individual single machine prototypes, including at test centres in Scotland and Wales. But there are also two companies who have got early arrays, what they call the first commercial arrays. One of them is a company called MeyGen, and they've got six turbines at present just off the North coast of Scotland. And there's another company called Nova Innovation who have, I think, three or four turbines in the Shetland islands.

sun and sea

34:23 - A golden decade for tidal energy

Tidal energy is finally engaging with government's subsidy systems in the same manner as solar and wind

A golden decade for tidal energy
Stephen Wyatt, Catapult

Much of the stilted progress in the marine renewable space is predictably down to cash. Stephen Wyatt is the director of emerging technology at catapult. Catapult is a not-for profit network of innovation centres that help to link up businesses, bright ideas, and funding to get good high potential ideas as they put it into the marketplace. Chris Smith asked Stephen what the landscape for marine renewables looks like at the moment...

Stephen - The landscape for marine renewables is generally positive at the moment. There is a huge push towards net zero and offshore renewables generally have been identified as being a key part of the future energy mix.

Chris - Well you say it looks positive, but we've just heard from our previous guest that actually we are back in the 1990s in terms of the comparison between where other renewables are and marine renewables. So are you saying there's a lot of potential? It just is waiting to be realised?

Stephen - I think for things like tidal stream energy they are still in the development phase. We've spent the last 10 or 15 years moving from the lab scale prototypes through to full scale prototypes. And as we've just heard the first commercial arrays. We now really are in the place where we're looking to get genuinely commercial and moving to engage with the government's subsidy system that will allow us to move to that first phase of commercial projects.

Chris - Well, Simon Waldman was saying we basically learn by doing so have we got realistic technologies now that are actually enabling us to do that? And is there sufficient resource there to grease the wheels financially?

Stephen - We do have a handful of very credible technology concepts. Often these technologies are developed by small companies and the nature of the grant funding can be a little bit stop start. And of course they have to convince private sector investors with the right risk appetite to come in. So I'd say it's been a little bit of a turbulent journey, but we are now thankfully in the place where we have a number of credible concepts ready to scale up to these commercial arrays.

Chris - How much are the government putting up? Because obviously this is being led by governments. When you've got a big problem which needs somebody to de-risk it a bit, the way you de-risk it is governments give grants and that kind of thing. So how much potential funding is there?

Stephen - So historically tidal companies have received from government have received capital grants. And it's been a bit stop start as I say, but typically that's been between 10 and 20 million pounds per annum, but that's not a lot when you try...

Chris - Is that per project or is that for the entire field?

Stephen - No, that that's been in its entirety. It's not a lot when you sort of start looking across a number of concepts we're trying to progress here.

Chris - I mean, just putting that in perspective, just building one wind turbine costs 4 million. So, when you think you're now dealing with a very different environment where the exigences of being in the marine environment are huge, aren't they, 20 million is nothing.

Stephen - I think that's right. I think the tidal energy companies have worked incredibly hard to make a small amount of public funding go a long way. They've also had a bit of a hiatus in funding in recent years, but now thankfully due to a large part of lobbying by industry, we now have a subsidy regime in place that will allow them to tap into the same sort of project funding that we're seeing for things like offshore wind and nuclear. So if you like tidal stream, despite some of the headwinds of developing the technology has now come of age and they're able to bid into the same sort of subsidy pots as more established technologies,

Chris - We were hearing just now that, um, the prediction is that perhaps 10% of what we need in energy at the moment is potentially source-able from tidal stream and so on. Does that seem realistic to you? And do you think we are on target to get there and over what sort of time scale?

Stephen - Our sort of own analysis probably puts the figure a little bit higher than that? Definitely think it's realistic to assume that tidal stream will make a material contribution. It's there, it can be tapped into now, but ideally we want to continue to drive technology development, bring the cost of generation down a little bit more, and then we can start deploying commercial scale. My view is we're at the start of a golden decade here. And so over the next 10 years, we're gonna see tidal stream move at a rapid pace. Similar to the journey we've seen for things like offshore wind, where costs have more than halved over the last five years. And I think with the appropriate deployment levels, we'll see that happen again.


Tidal pool

39:23 - Testing Tidal Stream Generating Technologies

Tidal technologies and prototypes are put through their paces in extraordinary facilities like these...

Testing Tidal Stream Generating Technologies
Luke Myers, University of Southampton

In the emerging field of marine renewables, tidal stream technologies need to be rigorously tested before being deployed in the open seas. The industry has settled on a design that resembles structures found on onshore wind farms; testing their efficiency in the lab is Luke Myers. He's an associate professor of marine energy and micro-renewables at the University of Southampton, Harry Lewis paid him a visit...

Luke - So my stock answer when I'm in the pub and people say, what do you do? I say, underwater wind turbines. And that's because the tidal industry has quite quickly narrowed down onto a marinized version of a wind turbine. Previously, we've had a few sort of more novel designs. We've had vertical axis, and historically we've had wind turbines like that. And we've had some that have been like one of those lawn mowers that spin round, you know, with their blades out the front. We've also got them in ducts. So, basically channeling the flow through the blades. And then finally, we've had some sort of flapping hydrofoils that look a little bit like a dolphins tail.

Harry - So lots of prototypes. And why is it that the industry seems to be settling on an underwater wind turbine?

Luke - I think because that way there's a lot of technology transfer between wind and tidal in terms of things like the power train and the electronics and all that sort of the back end of the system, fundamentally it's mechanically identical.

Harry - And so go on then what have we got in front of us?

Luke - So we have something that's broadly similar to a lot of the devices you might see on the internet. Now it's a three bladed upwind or upstream tidal turbine. The diameters are reconfigurable so we can put different size blades on them. It depends on the amount of force that the model can take and also how much electricity we generate as well.

Harry - You've pulled out a different blade and what's most startling about it is the fact that it's bright gold. So it looks fantastic. Also the wing tip is slightly different. What's this got to do with the prototype that it is in front of us?

Luke - Okay. So the reason it's gold is that this is aluminium is anodized to stop it corroding.

Harry - So this is on purpose. It's not just a style choice.

Luke - No. With the blades, we have to keep a very precise shape on them. So if the shape changes through corrosion or any sort of biofouling, it ruins the performance. The uplift at the end of the blade is what you see on most commercial passenger aircraft, which is they're called winglets. The idea is that they stop turbulent flow, falling off the edge of the wing and what that does, it creates drag for an aircraft. So it reduces the performance. It does a similar thing for a tidal or a wind turbine as well. The cost of adding a winglet to a blade is really quite cheap when you're making your blades out of glass or carbon fiber. So, it just needs a different mold. And then the material cost is relatively small. And we found an increase in the rotor power, almost 10%, which is huge.

Harry - When you found this out, you sent this to one of the commercial companies that you've been working with as a research facility. What's that relationship like between industry and research at university or other educational facilities?

Luke - We are trying to liaise and work with an industry that is highly competitive because it's at that nascent sort of development stage. So sometimes for us, it's quite difficult to work with multiple companies. So either on the same project or sequentially, but it''s completely understandable that if they have an industry advantage they want to keep that. So when we discovered the uplift and performance from designing the winglets, I realised we needed to get the results out fairly quickly. So, I actually contacted one of the large manufacturers via web form and said, I've got this amazing research and I'm happy to give it to you straight away. And so three people came back on the email in touch, sounding very excited. Then it turned out that they had no idea that we did any of this work, no idea that we had all the facilities and the capabilities that we do. So it kind of goes to illustrate just how sort of insulated and busy, you know, these sort of companies are. They don't have the resources to check up on what we're doing. So unless we're working together directly on a research project, they may never know of what we've done.

Harry - And they might not know, like you said about all the facilities that you have here. And hopefully if there's someone downstairs, we might get to have a look at the I've forgotten what the room's actually called again.

Luke - At Southampton we have the UK's largest towing tank, which is effectively a very large swimming pool with a wave maker at one end and a motorized carriage that zooms up and down. So we'll go and see that.

Harry - It looks a little bit like something out of Q's testing lab at the bottom of MI5 or MI6.

Luke - And obviously you get the awesome echo as well.

Harry - So when it comes to taking that prototype of yours that you've got and placing it in the water, what's the process here? How does this facility help you?

Luke - It's a body of still water. It's 138m long. It's 6m wide and it's 3.5m deep. And what we can do here is we can tow things like model ships and vessels and tidal turbines through this body of water. There's also a 0.3 mm difference from one end to the other to account for the curvature of the earth, because of the length of the tank. We have a 6.5m wide carriage at one end, and that is towed via a overhead cable up and down this tank backwards and forwards up to about 12mps, which is frighteningly fast if you're on board.

Harry - Oh, so your turbines, in this instance, they're not sitting on the bottom of the pool. They're actually being dragged through to give the impression of a current?

Luke - In a similar way that a wind tunnel works. So you could have a formula one car that's going around a circuit and you could measure the forces on it. Or you could make it still in a wind tunnel and move the air past it. So that's often what we do in engineering. The advantage of this one is that we're not moving the water, which takes a lot of energy.

Harry - When it comes down to the prototypes that you produce and what's on the market. How efficient are these wind like turbines that go underwater?

Luke - So our relative efficiencies for our models alone are comparable to full scale wind turbines already. So we get a, what's called a coefficient performance. For our small models is around about 0.42 and the largest wind turbines around about 0.5 something. So, for that coefficient performance, that efficiency gets better as you get bigger.

Harry - And what does that mean?

Luke - That's a proportion of the available energy that you can turn into electricity. So for example, if you take a coal fired power station, it has a similar coefficient of around about 35%. So for every three units of coal, you burn, one unit goes into electricity and two get wasted as heat and other losses.

Harry - So do you think that technology's going get better and be able to take on even more of that energy that those currents are producing?

Luke - Yeah. So we have some currents which are frighteningly fast, especially up around the western coast and up to the north of Scotland. They're around about 5mps? So that's 10 knots. For reference, one cubic meter of water weighs the same as a family car. So for every square meter of area, that's five family cars hitting you every second. So its epic amounts of engineering term, epic amounts of kinetic energy.

Harry - And compared to wind that that's not under nearly as much stress, because the stuff must be moving quicker, but at the same time, far less dense.

Luke - Yeah. So tidal turbines, the thrust force per unit area. So the amount of stuff that's hitting you per unit area is orders of magnitude higher. It's much greater. So tidal turbines will be much more compact and much smaller. We'll never see 80m diameter tidal turbines, because the forces are so great underwater. So they'll be far more far more compact and smaller and sort of hidden under the water

Harry - Again in comparison to wind turbines, how much energy are we able to take from a single tidal turbine compared to a wind turbine?

Luke - I think ultimately it depends how big tidal turbines get. At present because of the high forces and the efforts you need to make to resist those forces, effectively so your blades don't snap off. Current thinking is that around about 20m in diameter is going to be the maximum for a tidal turbine. Now the power output depends on the speed of the flow, but really roughly I think individual turbines have between one and two megawatts.


48:48 - The O2 Tidal Generator

The world's most powerful tidal turbine...

The O2 Tidal Generator
Andrew Scott, Orbital

Relatively few companies have demonstrated commercial viability in open sea tidal stream trials. In order to receive government support, companies must be producing electricity and supplying that to the grid. This stage of development is sometimes referred to as the valley of death. When a startup has begun operations, but not generated revenue. This is sort of where all the startups in the marine renewable space are. One of the pioneers in this space is Orbital. Their CEO Andrew Scott tells Chris Smith about the O2, a device currently generating electricity off the shores of Scotland...

Andrew - Our technology's a little bit different, very innovative. It doesn't look like a wind turbine, a miniature wind turbine bolted to the bottom to the sea bed. Some people kind of think it looks like a spacecraft or an aircraft. So it's got two big wings and a fuselage and actually the whole thing floats. And at the end of the wings, we've got our power trains. So there's two power trains, one at either end and it's anchored on site with a big set of moorings and the wings are hinged, so they can come up to the surface so we can get access to everything at low cost and then they can drop down to start generating power.

Chris - Now, when you say power trains by that you mena the turbines for want of a better phrase, that's going to extract the energy from the water flowing past your structure?

Andrew - Yeah. As one of your previous guests was saying it's a very similar technology to actually generate the power as wind turbines. Some people call them the cells or power trains, but it's really the rotors that take the kinetic energy and turn it into rotational energy. And then you couple that with a gearbox and a generator.

Chris - And how big is the whole thing?

Andrew - Yeah, that's the other thing that will probably surprise people is it kind of looks like a plane and it actually is about the size of a jumbo jet 747.

Chris - And how much juice comes down that cable?

Andrew - The turbine that we've built and launched last year, we call it the O2, it's the world's most powerful tidal turbine. And when flow speeds get up to 2.5 mps, it reaches rated capacity, which is two megawats per hour.

Chris - Would you then envisage a fleet of these that you would anchor in optimal locations, presumably so they don't all interfere with each other or bash into each other, but you would therefore be optimising the extraction of energy from where the tidal flow is fastest?

Andrew - Yeah, absolutely. In the same way that you get wind farms that are multiples of 1, 2, 3, 4 megawatt turbines we envisage that we would have multiple of these inner tidal stream sites that are all generating power onto a cable back to shore.

Chris - And I suppose one of the massive advantages of doing this is that because the tide comes in and out twice a day, you know, when, and so it makes the generation and therefore the provision of energy that you know, is gonna be there very predictable and therefore very reliable.

Andrew - Yeah. That's the beauty of tidal stream energy, you know exactly how much energy you're gonna produce and you know exactly when you're gonna produce it. And there's actually value in knowing when you're not gonna produce it as well. If you've got planned maintenance and things, you can schedule it for times when there's very little or no tide. So you can do work without really disrupting the overall performance or yield of the turbine.

Chris - One of our other guests was pointing out that, you know, it's a pretty harsh environment the marine environment. I suppose that by having something that is not stuck to the seabed, you can lift those wings up to get to the business end of the operation quite simply, you've actually made it much easier to maintain. And therefore you presumably have saved quite a bit of money?

Andrew - Yeah, absolutely. There's kind of a golden rule or a rule of thumb in the offshore environment. A job that will cost You maybe a pound offshore will cost you 10 pounds offshore at the surface, but it'll probably cost you a thousand pounds at the bottom of the sea bed. So, being able to get access to equipment quickly and cheaply on the surface is absolutely key.

Chris - When is this gonna be realised? So it is actually beyond the prototype generating little bits of power stage?

Andrew - Well, O2 two is generating power right now into the UK grid. So, we built it and launched it last year from Dundee. The aspirations are, and we're planning on building more of these in the coming years to start creating these arrays, both in Scotland and around the UK.

Chris - For comparison then Andrew. So if I build a big wind turbine megawatt for megawatt, what's it cost to have the same generating capacity with one of your devices?

Andrew - The average cost for a megawatt offshore is probably today around about 3 to 3.5 million pounds per megawatt. And for us, we built the last turbine at just a little bit over 5 million pounds of megawatt.

Chris - So you're not far off what we're already achieving with wind?

Andrew - No, not very far at all. Now the overall cost of energy is a function of a lot of other things. Obviously your resource is free, but how you generator performs, you know, one of your previous guests was talking about improving the performance of rotors and all these sorts of things. So these are things that wind have benefited from for the last 20, 30 years. And indeed they've benefited from a volume of scale, economies of scale. So those are all things that have allowed their overall cost of energy to come down a lot and certainly landing where we are from a manufacturing cost where we are, we think is, you know, really exciting.

Chris - Have you now got an order book then to do this, not just for the UK, but internationally, or is this still very much at the stage of hand to mouth? It's making some electricity, you're proving the point, but you're still waiting for those calls to come in?

Andrew - Well, we do have commercial projects here in the UK and we anticipate this summer, we should get clearance from government support hopefully to move forward with them. And indeed, actually we've got another turbine to build and put up in Orkney and combine with an electrolyser and battery storage as well. So yeah, we're moving forward, with some exciting commercial projects here in the UK and we're seeing definitely an up turn of interest from regions around the world that have got tidal stream energy that are very interested in what we're doing.


55:33 - QotW: why do our senses of smell differ?

Her in the UK fields of rapeseed run parallel to the roads, can you smell them?

QotW: why do our senses of smell differ?

When traveling to The Naked Scientist's office, I end up passing through a series of fields. And let me tell you, I wish I could block out some of those smells. Here to explain the situation of your partner's ability to smell is professor of neurobiology, Sandeep Robert Datta from Harvard Medical School. But before that, we should first understand how we even smell in the first place...

Sandeep - Smells are actually detected in your nose by specialised cells called 'olfactory sensory neurons'. These neurons detect smells because each expresses a specialised odour detector called an odour receptor. Your genome actually encodes about 400 of these different receptors and each one of these receptors is specialised to interact with a different set of odorants. You can think of each odour receptor as like a lock, and an odour like a key. Odours float into your nose and when they find the matching receptor, when the key finds the lock, the receptor gets turned on and the neuron gets activated.

Otis - These neurons send signals to our brain telling us what the scent is. However, individual receptors come in unique variants, which lead to everyone having a different selection of receptors in our nose.

Sandeep - It turns out, for at least some smells, your ability to detect the smell and your perception of smells can depend on the specific receptor genes you've inherited from your parents. For example, there are some people who love the smell of male underarm sweat, while to others it's disgusting. The reason different people have different perceptions of that particular odour is because they've inherited different versions of the gene that encodes the receptor for male underarm, sweat.

Otis - And here I was thinking that deodorant was essential to make armpits smell better. So genes are a likely cause of why we have different smell receptors, and therefore while your partner may not be able to smell certain scents. It doesn't matter how strong the smell is, if we don't have the right receptors our brains won't detect for smell.

Sandeep - That isn't to say that genes are everything. Smell perception also crucially depends on our experience of smells both recently and across the lifetime. But genes are the most likely explanation for what's going on between you and your partner, assuming that you and your partner both share a cultural background and have shared most of your recent olfactory experiences.

Otis - Thank you to professor Sandeep Robert Datta for helping us sniff out that answer. Next week, we'll be looking at this communication conundrum from listener Mike.

Mike - Does email and texting affect our brain's cognitive functions?


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