Professor Patricia Thornley, Energy and Bioproducts Research Institute and Supergen Bioenergy Hub, Aston University: Bioenergy role in electricity production and sustainability issues

Professor Patricia Thornley: Hi, I'm Patricia Thornley. I'm based at the Energy and Byproducts Research Institute at Aston University, which is right in the centre of Birmingham. I'm not there today, I'm at home as I'm sure all of you are as well, but it's great to be joining you on this online platform. So I'm going to talk through for you bio energy and the role that it plays in our electricity supply in the UK.

I'm going to move on now to my second slide. So this is a picture of what electricity generation in the UK looked like in 2018, and what you can see on the right hand side, you've got a mid-blue colour there and that is the bio energy generation. Sorry, this is for UK renewables. So bio energy is about a 1/3 of the UK renewable supply in 2018, the last year for which we have full figures. For comparison, the purple that you can see on the left hand side, the next biggest one, is onshore wind. And the green one that you can see down the bottom, which is the next biggest, is offshore wind. So each of those are roughly about a 1/3, and then we've got solar PV and hydro waning at much less than any of those.

I'm moving on to slide three. So that was a snapshot of what it looked like in 2018. The question is, how have things been moving over recent years? I think you all know that we've been producing more renewable electricity in the UK year on year really. If I look here, just at the biomass to electricity, what we see is that between 2017 and 2018, the amount of electricity that came from biomass went up by nearly 10%. 9.4%. Now, where was that coming from? A lot of it came from very small power stations. In 2018 there were actually 58 new power stations built all around the UK from bio energy. Most of those were things like in factories where they were self supplying, the electricity being used for manufacturing, or where they were providing heat and power at the same time. But there were two big ones that came on in 2018, and both of these were conversions of coal fired power stations. So these are really old power stations that have been on the system forever. They've been burning coal. A few years ago, Drax, which is the largest power station in the UK, converted some of its capacity to biomass, and it increased that significantly last year in 2018. Now I've said here that it used plant biomass capacity. What that means is that most of what is used in Drax is actually forest residues which are imported, and I'll talk about the sustainability of that a little bit later. So forest residues are the stuff that gets thinned out of our forests in order to keep them healthy and to maintain the growth. It's normally left lying on the ground to just decompose, but we can collect it and use it for energy. But the other big one that came online in 2018 was Lynemouth Power Station, which was using wood material and that was 420 megawatts. Megawatts are a measure of how big a power station is, how much capacity it has to deliver energy to people. And two other types of bio energy are energy from waste and landfill gas.

So I'm now moving on to slide four. Okay, so bio energy can come from lots of different sources, and I've got pictures of lots of them here. On the top left, we've got wood chips. On the top middle, we've got wood pellets, and that's where we take the wood, grind it up into tiny bits and then compress it to make it really easy to transport. And this is the sort of stuff that is coming into the big power stations in the UK at the moment. If I pick another one on the left hand side in the middle, you can see some willow, a really fast growing tree that can be planted specifically to provide bio energy. And if I look at the bottom middle section, this is the first power plant I ever worked on, this is in Fife in Scotland. When you have chickens and you're rearing them, in their houses you put wood chips in the bottom, the chickens poo on the wood chips and then you take that out at the end, and here we're using a power plant to turn that chicken litter into electricity.

I'm going to move on to slide five. Okay, so there's lots of different types of biomass, and there's lots of different ways of converting it. We can do this thermally where we tend to involve high temperatures. We can do it chemically, which we tend to use when we're trying to turn it into fuels or chemicals or materials, and we can do it biologically at low temperatures. We can turn the biomass in that way into heat, into electricity, into chemicals or into transport fuels. And I know that the people who have been involved with transport fuels, you've been picking this up in another group looking at synthetic fuels, but today we're going to concentrate mostly on biomass for electricity.

I'm moving on to slide six now. Okay, so a lot of people get concerned about the sustainability of biomass, and if you are concerned about that, I would point you to this report which was done by the Committee on Climate Change in 2018. They reviewed all the evidence around biomass and I've given some of the quotations here from it. And they said that biomass can be produced and used in ways that are both low carbon and sustainable. They said it can make a significant contribution to tackling climate change. But at the same time, they said there are risks that biomass production and use could in some cases be worse than the alternative of the fossil fuel. I think when you've seen some of the previous slides I showed with so many different possible types of biomass, so many different conversion technologies and so many different uses that you can put it to, it should be pretty clear that there's actually loads of ways of doing this. There are good ways of doing bio energy, and there are bad ways of doing bio energy. So getting the right balance is really, really important here, and it's really important that people know what they're doing and that this is properly regulated. I'm going to move on now. Okay, so when we look at the potential role of biomass, we reckon that in the UK, with just UK grown resource, we could provide about 45% of the UK energy demand. Now, that's more than just electricity. Biomass can provide electricity, but it can also provide heat or it can be turned into fuels. So when we look at this, my personal opinion is that probably about 10% of our electricity should be coming from biomass and the rest should be going into heat and fuels. The reason I would limit that to around about 10% is that there are other ways of producing electricity. You've got wind, you've got PV, you've got the stuff that I showed you earlier, and it doesn't make sense to use all the biomass for electricity when there aren't other ways of producing the chemicals and the materials that we need, because biomass is the only source of renewable carbon on the planet. Also, biomass can produce high grade heat.

Moving to slide eight. So when we look at sustainability, it's about more than just carbon, and what I plotted here is 36 different things to do with sustainability, including things like air quality, job creation, a whole host of stuff. The blue circle is looking at fossil fuel oil, and the idea here is that if things get more sustainable then that circle is stretched. I've shown a purple splotch on top of that which is biodiesel, and for some things, the purple splotch is more sustainable. You can see for about half a dozen of them, it's actually stretched out and got bigger. But other things have got worse, and there are always going to be trade offs here. We have different ways of providing our energy, which have different impacts. But it's never the case that one thing is entirely more sustainable than another.

I'm moving on to slide nine. One of the other really contentious things about bio energy is its carbon balance. This is captured here in a comparison between coal and the example I have here, let's say straw. And the point is that when we take coal and we burn it, we send carbon dioxide up into the atmosphere. When we take straw and we burn it, we send carbon dioxide up into the atmosphere. Both of those amounts of carbon dioxide in the atmosphere cause climate change. Okay, so it is true that when we release the carbon in biomass to the atmosphere, we are contributing to climate change. However, what it's important to realise here is where that carbon came from. That's what you can see in the bottom half of this picture. It's a cycle. So as we've said, the key point is that the straw absorbed carbon dioxide when it grew. So this isn't carbon dioxide that's been locked up for 150 years now being re-released and causing climate change. This is carbon dioxide that got removed from the atmosphere last year, now being put back again. I always draw a comparison here between the difference between my savings account and my current account. And when I'm releasing coal and the carbon dioxide from that into the atmosphere, it's like raiding my savings account that I put away for a rainy day. I'm releasing the carbon stocks in a fairly frivolous manner to the atmosphere and causing havoc. But when I do this with biomass, it's more like my current account, because that stuff has come from the atmosphere relatively recently and I'm just returning it back again. And I know I'm going to get more coming in again next year. So it's like I'm simply topping up the seesaw of carbon coming in and out of the planet with my biomass, and if I can get energy out of that at same time, then that's a good thing. I'm not, with biomass, contributing to the long-term increase in carbon that we associate with climate change.

That's my final slide. More information at this website or more pictures from the comic that I used in the previous at this one. Thank you.