# Transcript

Interviewer
So in terms of say the basic person on the street that was coming into science with sort of very limited knowledge, how would you define what a biofuel is?
Chris Somerville
Well of course the term generally refers to two types of material. The most common type is woody biomass or woody materials that are generally just burned directly for heat. And the other type are gases or liquids such as biogas or ethanol, biodiesel that are made from biomaterials. So actually I think it's one of the difficulties of discussing the area, is that there's many types of biofuels and there's many different ways to produce them so there's a vigorous public discourse about biofuels but actually much of it is not very correct in some way because it - the discourse - tries to treat it as though it's a single subject but actually there's many different subjects. For example, there's many ways to produce ethanol. Some are environmentally positive. Some may be environmentally negative. And so inevitably in these discussions what happens is one side of the argument picks one scenario and the other side picks another scenario and they end up talking past each other.
I
That's an interesting point and one of the questions we've got down is what is the biggest misconception about biofuel production or usage?
CS
The kinds of issues that are, I think, there's a lot of misunderstanding about is like the net energy return. Some types of biofuels, I think, don't have a positive net energy return, that is the amount of energy it takes to grow and process the material to a fuel. But certainly other types of biofuels look to us like they're very net energy positive. And so similarly the same things are true for greenhouse gas emissions. I think there are some types of so-called biofuels that could be very negative for greenhouse gas emissions. Partially through kind of indirect effects, that is, if you grow biofuels on a drained swamp in Malaysia that's gonna be very negative because as soon as you drain a swamp the greenhouse gas emissions out of that swamp will dwarf the rate at which the plants that you plant can possibly take up the CO2 for a century or more. And I think there is also a sense that there is not enough land for food production which is really strongly wrong. There is a tremendous amount of land. We use 12% of the land worldwide roughly for food production.
I
And what percentage do we currently use for biofuels?
CS
Oh it's a tiny fraction. It doesn't show up. It's like point zero zero something per cent.
I
So I guess there is a lot of scope to increase significantly if people think that's a reasonable thing to do?
CS
Yeah. Let me give you an example where I think the public discourse is not very clear on the matter. So in Brazil the Brazilians now get about 40% of their transportation fuels by fermenting sugars from sugar cane. And the amount of acreage required to do that is about four million hectares. Now that may seem like a lot if you're living in Great Britain but to put it in perspective there's 234 million hectares used to grow cattle, with about 1.4 cows per hectare, so way below the carrying capacity of the land. So the Brazilian government has calculated that with the small intensification of the cattle they could free up 57 million hectares for sugar cane production. So from the 4 that's currently used for fuels, there's 4 for food as well, so 4 for food, 4 for fuel. If they expanded it to 57 million hectares and used both the cellulosic material as well as the sugar, our estimate is that could produce almost a third of the fuel in the world - transportation fuel. So that's just in one country. So when we look at how much is possible worldwide, it certainly seems to us like quite a large amount. Around the world there is a billion acres that's been abandoned to agriculture and this is all land that at one time did grow crops.
I
And I guess that there is always an argument that some of the land that is being used for biofuel could be used for food production.
CS
Yes and that's certainly true but of course you must be aware that in the last two generations the major problem in food production has been over production in the developed world so we pay farmers mostly not to produce. The numbers for the subsidies in Europe and North America to keep farming out of production, I believe it's more than 100 billion dollars a year. And in Africa the average crop yield is about one-third of what it does in the developed world? Because of lack of investment we live in a world economy now where I think we are going to have to use the regions of the world that do have abundant land to provide the food and fuel.
I
What crops in your view have the greatest potential for acting as biofuels?
CS
We are particularly interested in perennial species that can be used to produce large amounts of total biomass in a sustainable way with net energy and greenhouse gas benefits. So the best species because of their high water use efficiency are types of grasses like miscanthus and switchgrass, so we are certainly investing in those. But we're also very interested in even more water efficient plants types of species called agaves - they're a kind of cactus like material - some agaves have higher sugar content than sugar cane. There's many species. So in Africa Agave sisalana has been grown on millions of hectares to produce sisal which is used for rope. Some of these species have ten times the water use efficiency of a plant like wheat or rice meaning that for one unit of water input they can produce ten times more dry biomass than a plant like wheat or rice and they're very, very drought hardy so we're interested in those for the semi-arid areas. There's a couple of billion acres worldwide that are too arid for agriculture but might be quite suitable for these kinds of highly water efficient, drought hardy species.
I
What is the biggest take home message about the potential benefits of biofuels compared to use of fossil fuels?
CS
Oh well obviously they are sustainable and if done right they can have a net positive greenhouse gas effect, I think. We can dramatically reduce the amount of greenhouse gas emissions associated with producing fuels by doing it right. You know if you track the discoveries of new oilfields they're relatively infrequent since there's been any major find and there's every reason to believe that it will eventually run out. It's probably in the case of oil and gas in the 50-60 year time frame. Let me give you a number that's easy to understand to see what the challenge is. World energy use is currently expanding by about one billion watts, or so-called gigawatt, every 1.6 days. That's so you know I guess everybody knows what a watt is from a light bulb so think about a 100 watt light bulb well a billion watts is the size of a large nuclear power plant. One way of thinking about it is that energy use is expanding worldwide by about the output of one nuclear power plant every 1.6 days. So as an American - a profligate energy user, you know the United States uses 25% of world energy - my view is we need to get our country in order first. We've got to get a grip on our own energy production. We've got to clean it up and get energy efficient and then hopefully some of the technologies that we develop to accomplish that, they'll become available to other countries and hopefully those countries will feel the same imperative eventually to become energy efficient and put in place all the renewable systems.
I
So if I had to put you on the spot and give you a statement and just to see whether you would go along with it, so would you say that the future was and if not what is it?
CS
Oh no. I don't believe in a single future. I think can make a component, you know. I believe we could get 30% of our transportation fuels from biomass so it maybe in 25 years roughly 6% of our energy use might come from. Long run we will probably see some improvements in solar technologies maybe solar thermal maybe some improvements in photovoltaic manufacturing and hopefully some big improvements in photoelectric chemistry. But they are pretty far away. I hope we will see more geothermal, wind of course is ready and I think we need to see a lot of wind. One of the challenges will be to also develop better storage so I hope we will see some battery improvements that would allow us to you know store energy better.
I
So I'm picking up that biofuels is part of the answer and the answer itself is quite complicated and it's a whole combination of different things working together?
CS
Yes it's a combination of things. We need to use every - every renewable technology we possibly can to make change. Many students ask me how they can work on bioenergy. And while it's certainly possible there's many ways to work on plants in that context, I actually think it's important to remember that ultimately the land that we need to produce biofuels, you know, there's a finite supply and everything we can possibly do to improve agriculture will contribute ultimately to as well as the larger context of human well being. We need many other things besides energy. We need materials and fibres and fuels and feed and so I would say almost anything that anybody can do to improve plant productivity in a sustainable paradigm will contribute ultimately to the - the energy climate matter.