Southerly by David Haywood

11

New Zealand Biofuels, Part 2

This is a transcript of an episode of Public Address Science which was originally broadcast on Radio Live, 2nd June 2007, 2 pm - 3 pm.

You can listen to the original audio version of the programme by clicking on the 'Play the audio for this post' link at the top of this page or the 'Audio' button at the bottom of this page.


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Theme music...

Voiceover:

I fully admit that a few years ago I was something of a biofuels sceptic when it came to the replacement of automotive fuels in New Zealand. Since then, however, things have changed dramatically. The price of fossil fuels has risen enormously (a trend which is expected to continue), and new technology has come onto the scene which promises cheaper and less energy-intensive biofuels processing.

Recently, two New Zealand Crown Research Institutes -- Scion and AgResearch -- have joined forces with US enzyme manufacturer Diversa to work on automotive-type biofuels. Despite the criticisms levelled at some overseas schemes -- in terms of low energy yield ratio (and consequently high cost), as well as concerns over long-term sustainability -- the New Zealand consortium believes it has the answer to sustainable biofuels for this country.

I talked to Dr Trevor Stuthridge at Scion, and began by asking him to describe the feedstock and manufacturing process for their proposed biofuel scheme.

Dr Trevor Stuthridge

Our starting point is to ask: is it possible for New Zealand to convert one of its pulp-and-paper mills over to an ethanol facility?

So we're looking to use wood as our feedstock; and wood is quite a complicated material. It has both the cellulose -- which is what most people are using for next generation biofuels -- but it also has hemicellulose, which is another type of sugar polymer, and it has lignin.

The process that we're developing with Diversa is to look at ways of first physically and chemically breaking the wood down into pulp material -- which is where all the glucose that we use for the ethanol production is -- and also releasing the lignin, which we can recover for energy or chemical production, and also recovering the hemicelluloses, which are another

source for making ethanol.

So what we're doing in the first instance is physically and chemically breaking the wood down -- just as they already do in the pulp and paper industry. And then we're using Diversa's unique enzyme cocktails to break polymers [such as] cellulose and hemicellulose into their sugars.

And it's these sugars that we can pass on into another process with another bacteria, or a yeast, that actually ferments it into the ethanol. So in this way we can take a fairly difficult to break down material like wood, and turn it directly into ethanol.

Interviewer

Right, okay. So last week on this programme we also talked about biofuels and looked at the energy yield ratio for corn bioethanol in the US -- which is absolutely terrible -- only just over 1. Do you have a figure for the energy yield ratio for wood bioethanol using the Diversa process on this sort of large scale?

Dr Trevor Stuthridge

We're still working on that, so I don't have numbers at hand yet. In fact, we're going through that exercise at the moment as part of our feasibility study. But certainly our belief is that the energy yield ratio is favourable for lingo-cellulosics -- particularly derived from forestry resources. Management costs for the crop are rather lower (in our opinion), compared to food crops like corn, and the yield per hectare can be rather higher.

Interviewer

Now you've mentioned food crops -- and, of course, one of the criticisms of bioethanol in other countries is that it displaces food crops. Presumably this isn't a criticism that could be levelled at your scheme for biofuel manufacture?

Dr Trevor Stuthridge

We see this as a key advantage of what we're proposing, because much of the lands that the forests are growing

on are non-food quality. They're not suitable for food crops.

Certainly this is a key constraint in the United States, where the price of corn has now doubled because of ethanol initiatives. In some states up to half of the corn is being used for ethanol production, and that's starting to impact things like food prices and beef prices.

We think by targeting a non-food crop, and using essentially non-food quality land, we have a significant advantage. And certainly in New Zealand, from an international perspective, that's a key advantage to this country in our opinion.

Interviewer

That's reassuring. But another criticism of biofuels -- certainly in the US and Europe -- is that it takes a huge amount of land to produce just a fraction of the country's fuel requirements. Using your proposed method how much biofuel could feasibly be produced in New Zealand?

Dr Trevor Stuthridge

Our estimate is that a single pulp-and-paper mill facility could produce over 200 million litres per year -- and that would be quite sufficient to take us beyond E15 [i.e. a mix of 15 per cent ethanol, and 85 per cent petrol] in terms of fuel substitution.

In reality, if we took all of the forestry crops and the trees that we're exporting overseas -- it appears even possible that we could completely substitute in the long term. But, of course, there would be a significant capital investment required to process that sort of material.

Interviewer

Okay, right. But wouldn't there also be a massive cost incurred in terms of lost revenue from the wood feedstock that could otherwise have been exported as timber?

Dr Trevor Stuthridge

That's an interesting question and one that we're [considering] at the moment in our feasibility study -- because whilst at times wood and pulp can

be very financially positive, there are [also] times when it's non-profitable. So you get lots of ups-and-downs in that market.

With ethanol we believe we'll have a much steadier market -- so on average it's quite possible that ethanol production could even be better economically than current use of the forest resource.

Interviewer

You've pointed out that producing biofuels from New Zealand forests is no less sustainable than producing timber. But actually how sustainable is timber production in reality? Can the land keep on producing indefinitely?

Dr Trevor Stuthridge

[I think that] over the years the forestry industry and the wood-processing industry, have developed very good management strategies for the production of the wood stock, and the harvesting and replanting.

[So] this is still a pretty sustainable option for New Zealand in terms of land use -- we're not substituting for high-value land. I think management practices for forestry are pretty good in this country, from what I can tell.

Interviewer

I guess this is the $64,000 question -- but do you, at this stage, have any feel for the cost comparison to current petrol prices?

Dr Trevor Stuthridge

We don't have a strong feel for that yet. I think the challenge for ethanol at the moment is that in many parts of the world it's still heavily subsidized, and the price is still well above petrol.

The key challenge for ethanol in terms of cost of production is the enzymes -- and that's why our relationship with Diversa is critical to this initiative. I guess overall our aim would be to get the cost of ethanol being equivalent to petrol. We don't believe, as in many other parts of the world, that asking the consumer to pay more for their fuel is likely to be particularly well taken up.



I think New Zealand still has an opportunity to be a leader in this field, whether it's with pulp and paper or forestry or other crops. We're in a position geographically where being self-sufficient is probably the best option for us.

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Voiceover:

While it's perhaps a little too early to declare 'mission accomplished' on the transport energy front, the proposed New Zealand bioethanol scheme seems to overcome many of the objections that are made against overseas biofuel manufacture.

Given the scope for improvement in the fuel efficiency of New Zealand's vehicle fleet, sustainable biofuels could -- even in the medium term -- have a dramatic impact on our energy supplies. And, even if not completely perfect, they may well be a much better option than our current dependence on fossil fuels for transportation.

Theme music...

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Further information on biofuels:

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