Podcast | Food for fuel?

Did you know that your scrumptious donut can also fuel your car?

Fuels Scientist Renee Webster explains DST's research into biofuels and discusses the implications for military vehicles.


Edwina Callus: We all know that the food we eat gives us energy, but did you know that your scrumptious Krispy Kreme donut can also fuel your car?

Actually, in a round-about way, you probably did - we're talking about biofuels – liquid fuels that are produced by biological processes rather than the geological processes involved in the formation of fossil fuels such as coal or petroleum.

Biofuels receive plenty of attention because their use can significantly reduce carbon emissions – something that governments around the planet are striving to do.

Here in Australia, Defence scientists are exploring the use of these alternate fuels for military vehicles.

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Edwina Callus: Hi, I'm Edwina Callus with another podcast from Defence Science and Technology.

In today's podcast we're talking to Renee Webster, a fuels scientist with the Defence Science and Technology Group.

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Edwina Callus: Hi Renee, thanks for joining us on the podcast.

Renee Webster: Thank you for having me.

Edwina Callus: So Renee, while the concept of using Krispy Kreme donuts to fuel our vehicles is quite appealing, I should clarify that Defence is not actually thinking of using donuts as fuel.

Instead, I believe you're looking at using the waste products from primary industry as potential sources of biofuel, rather than the actual food products themselves. Is that right?

Renee Webster: That's one of the sources, yes. Particularly from sugar cane and other agricultural waste. We are also looking at non-food crops that are grown on land which is otherwise marginal or unsuitable and therefore not competing with food crops.

Edwina Callus: Why aren't we looking at food waste as a source of fuel? It's reported that huge amounts of food go to waste every day – rather than that food going to landfill, could it be a viable source of fuel?

Renee Webster: This is something that is technically feasible but it is a bit of a logistical challenge. We would be looking at collecting very small amounts and bringing them together in a central location. So while this is technologically feasible, it doesn't seem to be economically plausible at this point because of those logistical challenges.

Edwina Callus: What makes one product better as a biofuel than another?

Renee Webster: Traditionally, we have looked for feed stocks with a very high fat or oil content, but now as we see more production pathways coming onto the market; anything with a high carbon content can be viable so it's possible to use things like cellulose or lignin derived from plants and trees.

Edwina Callus: So what particular products are you looking at?

Renee Webster: So I've already mentioned waste from agriculture and there are also crops and things like algae can also be used. In addition to this, there's synthetic fuels, so these are fuels that are made using industrial scale chemical reactions, using simple molecules to create larger molecules that are appropriate for use as fuels.

Edwina Callus: Are any of the materials that you've looked at, are any of those standouts as a possible source of fuel?

Renee Webster: Most of the established technologies are using oils, fats, and some of these chemically synthesised processes. These are the ones that at the moment are producing the largest volumes and are the most well established in their technologies. So these are the most appropriate at this point in time.

Edwina Callus: And Renee, what's the focus of your research? Are you looking at the potential of the particular products as fuel, or are you looking that the implications of using those fuels on vehicles – for example, the impact on performance or cost or maintenance?

Renee Webster: Our focus is certainly more on the implication. What does it mean for Defence platforms if and when these fuels are being used to power them.

There are additional considerations of military vehicles, compared with the cars we drive everyday or commercial aeroplanes. They're operating in extreme environments or harsh conditions and we are looking after some of the most high performing and niche aircraft in the world.

So there are some unique considerations that need to be taken into account and we are tackling this by looking at the most fundamental components of the fuel, the molecules that they are made up of. What are the molecules and chemical reactions that are found in alternate and conventional fuels, are they different?

We want to find out as much as possible about these similarities and differences to make sure we can use them safely and efficiently.

Edwina Callus: I mentioned earlier that alternate fuels can reduce carbon emissions. I've also heard that they can actually extend engine life. Is that correct?

Renee Webster: It's definitely possible. Some alternate fuels have been shown to produce less dirt inside aircraft engines and fuel systems. So this means that less maintenance is required, and engines might last longer.

Edwina Callus: So Renee, is your research focused on a particular vehicle for these alternate fuels?

Renee Webster: We are interested in how alternate fuels will perform across all of the ADF's air, land and sea vehicles but right now we have a strong focus on the Joint Strike Fighter. This aircraft will be using fuel in a different way and in a more demanding environment than we have ever seen before.

So we want to make sure that both our alternate and conventional fuels are fully safe and effective options for this aircraft.

Edwina Callus: Does the use of alternate fuels in aircraft present particular challenges, compared to other vehicles?

Renee Webster: Ideally no. What we want is for these fuels to be what's known as drop in replacements. So that means that all the infrastructure to do with transport, storage and refuelling can still be used, and any platform or user of the fuel won't know whether the fuel is sourced from crude oil or any other feed stock.

Edwina Callus: What other countries, if any, are using alternate fuels in their military vehicles?

Renee Webster: The United States is really leading the way in this field and that's driven by a commitment from the US Navy to have 50% of all their energy derived from an alternate source by 2020.

Given that the US is a close ally, we must ensure that our platforms can also operate on these fuels for joint exercises and operations.

Edwina Callus: Is it realistic to think that the Australian Defence Force will soon be using alternate fuels?

Renee Webster: As I mentioned before, where we are operating jointly with the US Navy, and using their fuel, this is certainly possible due to their 50% renewable energy commitment.

Looking further into the future, it seems likely that alternate fuels will only comprise a larger part of the liquid fuel energy market. So it seems more of a question of when we start using these fuels, rather than if.

Edwina Callus: There were reports towards the end of last year that Australian technology was being used to turn old tyres into diesel biofuel. Is that something that Defence is interested in?

Renee Webster: There are some really great local technologies being developed for renewable fuels and that's certainly one of them.

At the moment the problem is that are comparatively small volumes being produced and military vehicles require specialist fuels which is quite a niche market. But once we see these technologies develop further, and the market become larger, it's foreseeable that Defence may use them in the future.

Edwina Callus: Thanks Renee. Now before we finish up, I want to get back to that Krispy Kreme donut. I happen to know that you have, in fact, extracted fuel from a donut. Putting aside the fact that you wasted a perfectly good donut, what did you have to do to the donut to extract the fuel?

Renee Webster: It's a fairly simple chemical reaction. First you have to extract the fat from the donut which we do with a common solvent. And then you simply heat it with either an acid or alkali material, to convert the fat into biodiesel.

Edwina Callus: And how much fuel did you manage to extract?

Renee Webster: Using this simple method, we can get about 150 millilitres of fuel from a pack of 12 donuts.

Edwina Callus: So, I'd need approximately 4000 donuts to fuel my car. Good to know!

You've been listening to a conversation with Renee Webster, a Fuels Scientist with the Defence Science and Technology Group in Melbourne.

It will be interesting to see what the future holds for alternative fuels, both in the commercial arena, as well as in the military.

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Thanks for listening to the Defence Science and Technology podcast.

You can find out the latest in Australian defence science by following us @DefenceScience on Twitter, or download the DST App from Google Play or the App Store.

The Defence Science and Technology podcast is a production of the Defence Science and Technology Group, part of Australia's Department of Defence. That's all for now. See you next time.


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Publish Date

April 2017

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