Skip to 0 minutes and 3 secondsToday I'm in the Stevenson Institute for Renewable Energy at the University of Liverpool with the Director of Institute Professor Ken Durose. And we're going to talk a little bit about renewable energy and the prospects for it in the future. Ken, I looked up a little bit of data before I came to talk to you. We all know the combustion of fossil fuels is causing terrible air pollution around the world. But I was very surprised to find that the five countries in the world with the worst air quality are home to about 40% of the world's population.

Skip to 0 minutes and 36 secondsSo I'd like to ask you for starters, what hope is there being able to replace fossil fuels as our main source of energy in the years to come? I think there's every hope that we can do that, but it will take time. The use of fossil fuels is still increasing, and will do for some decades. But by 2050, we'd expect that the fossil fuel power generation will be equaled by renewable energy power generation. So on that kind of time scale from now, we will reach parity, I think, in a generation of energy by the two different methods.

Skip to 1 minute and 12 secondsIt seems to require a crisis at every point throughout history for us to change our practise as human beings on this Earth generating energy. So in the 19th century, there were hundreds of thousands of deaths from respiratory disease caused by coal burning, and really that persisted up until the 1950s in Britain, when cheap coal was used in the 1950s in the UK. And that caused tens of thousands of deaths in London. But after that, there was a change in practise. Although there wasn't a move away from fossil fuels, things were cleaned up. But at this point in history, we're now faced with massive pollution, plus the need to reduce CO2 emissions for reasons of global warming.

Skip to 1 minute and 52 secondsSo there's a real incentive for the world as a whole to push towards renewable energy generation. So what do you think are the obstacles on the way to achieving this? We really have to change how we generate energy in a way that we've never done before. The scale of the challenge is huge. So within 20 years, for example, the predictions as to how our energy landscape will change show that there will be as much wind generated power as there is coal generated power now. And by 2040, we'd expect solar to achieve the same amount of power generation as coal has now.

Skip to 2 minutes and 37 secondsSo we are facing massive changes in the science and technology and the engineering to deliver this unparalleled amount of change. There's an opportunity. So I don't see them as challenges or obstacles. I think they're opportunities. We do have to do things in a way that we've never done before, so we have to keep our eye on not only engineering and developing current technology, but on looking for opportunities to do things we've never really done before. For example, converting CO2 into useful fuel to recycle it in a way, or generating hydrogen by catalytic mechanisms relying on, for example, sunlight. Those are new things. We do have to keep our eye on new opportunities as well as the development of existing concepts.

Skip to 3 minutes and 30 secondsAnd how do you think the laws of thermodynamics will influence our progress towards this vision? The rules of thermodynamics are design rules that will tell us what we can and can't do with energy. And renewable energy is rather different from fossil fuel generation, because it's so much more dilute. Wind, wave, the energy density is so much less than in fossil fuels or in coal, for example. So we know what's available in terms of the renewable resources, but how we get at them and how much we can get from them will be dictated to us by the laws of thermodynamics.

Skip to 4 minutes and 13 secondsSo, for example, a solar cell, we expect that to be no better than about 30% efficient at best because of thermodynamic restrictions. So technologically, we strive to increase the efficiency of solar cells to get close to that limit, or we invent completely different designs of solar cell that break that limit and invoke some different physics. And how does that level of efficiency compare with what we find in nature? For instance, in the trees and plants around us? Photosynthesis is a really beautiful process, and it has elegance that we can't match in the laboratory. So it converts atmospheric gases into plant material, CO2 is converted into plant material, and we can't do that as scientists.

Skip to 5 minutes and 5 secondsOf course, for thousands of years, people have burned that plant material-- wood, for example. And that's a very, very efficient thing to do. So if you look at the full life cycle of a tree and how long it takes to grow and how much sunlight that takes and how much wood you get from that and how much energy you can get from burning that and turn it into electricity, then it's less than a percent. Whereas solar cells that you can buy readily now have got efficiencies of 18% or even 20%. So although those efficiencies might sound low, actually, we're doing pretty well. We're doing fantastically. But so is the tree. The tree has evolved from its own.

Skip to 5 minutes and 46 secondsWe don't have to engineer or do anything scientific to make trees grow. They just do that for us. But I think my message would be keep your tree. It's a beautiful thing. Perhaps burning trees isn't the most efficient way of using the Earth's resources, but let's work on photovoltaics and see if we can't keep our trees, which are performing a useful job in reducing CO2, and generate your powers some other way. Great. Thank you very much.

Exploring energy issues

In this video Eann meets Professor Ken Durose, director of the Stephenson Institute for Renewable Energy at the University of Liverpool.

In the audio download (below) Eann meets Professor Graham Kemp, director of the Magnetic Resonance and Image Analysis Research Centre (MARIARC)

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This video is from the free online course:

Energy: Thermodynamics in Everyday Life

University of Liverpool