3.2 Affordable and clean energy

Number seven is affordable and clean energy. Now, this is a really important aspect because it relates to climate change as well.

In this picture, you will see a number of different ways of generating energy. So the first one, if you look at the green parts of this, they are biomass. If you burn wood, for example, that’s burning biomass, and the wood is formed by photosynthesis. Photosynthesis is driven by the sun.

And, in fact, all of these methods, with the exception of one, are driven by the sun. The sun is the only source of energy that we have coming into the planet, and we have to be able to use that if we want to have renewable energy.

So if the sun shines on the ground, it warms the ground. The air becomes hot. The hot air rises. That causes winds. If winds blow across water, that causes waves. If the sun shines on water and it evaporates it, it forms clouds and then rain, and we can have that as hydroelectric power. All of these are driven by the sun.

Photovoltaics, where you have solar panels, they’re solar driven. The only one in here that isn’t is the one in the front, which is geothermal energy, where you take heat from the Earth to heat other things. And, of course, nuclear energy is not run by the sun but is also not renewable.

Now, all of these methods have a contribution to be made from chemistry, and we need to develop them all so that we can have clean energy, affordable clean energy in the future, without using fossil fuels.

Now, you may say to me, well, wind energy has got nothing to do with chemistry, but it’s got a huge amount to do with chemistry. If you go to see these new wind turbines that they’re building in the North Sea, the blades are 200 metres long – 200 metres. It would take Usain Bolt 20 seconds to run along them. It’s fantastic.

But think of the chemistry, the material science, the engineering that goes into making a blade like that, which will stand out in the North Sea rotating in 100 mile an hour winds and produce energy. It’s a fantastic challenge. So all of these have a lot of chemistry in them. So there’s an opportunity to develop new ways of converting solar energy.

Now, when we think about how much energy we require, we need to think, do we have enough energy from the sun? Well, if we convert solar energy with 10% efficiency, we would indeed have enough energy to supply the whole world if we covered an area the size of Libya. Now, I’m not suggesting we cover Libya in solar panels. I don’t think they’d like it very much. But, of course, when you think about it, we have all these deserts in the world. We have the Great Australian Desert, the Gobi Desert, the Sahara Desert, the Kalahari Desert, the Mojave Desert, the Atacama Desert. All of these are places where there’s just sand and nothing else and sun. Could we harness that sun to produce energy that we could then use around the world? And there’s a lot of work going on in this, but the conversion of the sunlight and the storage of the energy are the really interesting problems.

Now, one fascinating idea is, of course, that you could convert water to hydrogen, and hydrogen is an excellent fuel, and you could burn it. And sunlight has enough energy in it to do this. Now, you will realise that doesn’t happen because – and it’s a good thing it doesn’t happen because if it did happen, you’d be sitting down on the beach. You’d be having your barbecue. Sun come out. Hydrogen would bubble off the sea, and you’d be blown to smithereens, and it wouldn’t be a good idea.

So people are working on trying to find catalysts that you can put into the water which will allow it to happen, and they’ve made a lot of progress, and that could be one way of doing it. But there are other ways which are probably more likely to work, and the most important one is electrolysis, and I mentioned electrolysis before. Passing a current through water converts it into hydrogen and oxygen. We can burn the hydrogen. And, of course, when we burn the hydrogen, we get water back again. So it’s a totally circular system, cyclical, renewable, no carbon, perfect system.

And we could do this from overproduced electricity from wind, solar. So, for example, in the North Sea when the wind is blowing at night and people aren’t using their electricity very much, we’ve got a lot of excess electricity. Now, what they do at the moment is they pay people to turn the wind turbines off, but what we should do is we should use that electricity to electrolyse water and produce hydrogen, and this can be done.

But let me talk about now the production of hydrogen because the production of hydrogen is very important. We do it at the moment, and I mentioned before that we do it particularly for the Haber-Bosch process. There, as I said, we take natural gas. We put it into a factory. We go through these processes that I described, and all the carbon dioxide is released into the atmosphere, and it produces huge amounts of carbon dioxide, and you see there I’ve put the number.

One possibility is just continue to use that process but to trap the carbon dioxide by pumping it underground. This is called carbon capture and storage, and the idea is it will go into old oil mines and old coal mines. It’s not being developed yet in the UK. Some is done in Norway. Some is done in the United States. But it’s not a particularly good process. As I say, the best way to do this would be by electrolysis, and we’ve got to see that the demand could be something like seven times what we’ve got at the moment. So we’ve got to have a huge amount of this hydrogen if we want to use it as a fuel. But this is what we’re aiming for, and this is a very, very important thing.

The main problem with electrolysis is that it’s quite efficient, 70% to 80% efficient, but it uses electrodes which are based on rare elements, not readily available elements such as platinum and iridium. So what we need to do here is we need to develop ways of electrolysing water, which will produce the hydrogen using non-rare and endangered elements.

And my friend Bruno Chaudret, who works in Toulouse, has done this wonderful piece of work on electrolysis. What he does is he takes iron carbide nanoparticles and supports nickel on the outside of them. He sticks these onto a graphite electrode, and he then passes a magnetic current over them. And the point about the magnetic current is the iron carbide particle is magnetic, so it flips the domains of the magnet, and that heats the particle without heating the water very much. And it allows you then to have a different kinetics, which allows the reaction to go at low temperature.

Using this type of electrode, they’ve been able to reduce the overpotential for oxygen production by 200 millivolts and for hydrogen production by 100 millivolts. To do that, normally without this kind of electrode, you would have to heat the system to 200 degrees centigrade. In this case, the temperature of the water rose only five degrees, and that’s because, of course, the particles are warming, and so they warm the water a little bit.

This is the kind of thing we need to develop. We need to develop new electrodes and new processes for doing the electrolysis of water.

Now, you may say to me, is hydrogen safe? And obviously there have been some really serious disasters where there have been hydrogen explosions. In this picture, you can see theRR2, which was an airship which blew up. But what’s important about this picture is to look at the flame. The flame is above the airship, and that’s because hydrogen is extremely light, and when it burns, it burns upwards.

So, in fact, in this accident, not many people in the airship died because the hydrogen and the heat went upwards. Some died because the infrastructure burnt. Now, if that had been petrol, it would have gone down onto the ground. It would have run along the ground. It would have incinerated all the people on the ground. So, in fact, hydrogen is safer than petrol, although it can explode, but petrol explodes in engines anyway.

And I’m old enough to remember when we had town gas. Town gas was half carbon monoxide, half hydrogen. We used to burn it in our cookers. We used to put it in pipes all around the country, and we used to store it in gasometers. So we know how to handle hydrogen, and it is intrinsically safe because it’s so light.

I thought I’d show that to you with these two hydrogen balloons that I have here. So these two balloons are filled with hydrogen. And if I’m telling the truth, if I burn this top balloon, it will not burn this bottom one here.

So let’s try it and see. I’ll just move some of these things out of the way so that we don’t get into trouble. Put my safety glasses. Right, so what I’m going to do is I’m going to light the top balloon, and the idea is that it should not light the bottom one because the flame will go upwards.

So I’m going to burst the top one and see what happens.

[David sets top balloon alight with a small flame. The top balloon explodes upwards leaving the lower balloon intact]

And the bottom one survived. So clearly the heat didn’t go down or it would have burnt it. And just to show that I’m not cheating, I’m now going to burn this one as well. If you don’t like loud bangs, please put your fingers in your ears, but watch this because what I want you to see is the fireball that comes from it going upwards.

Here we go. Do you see how it went upward?