Carbon-neutral liquid fuels for NZ
Transport is reponsible for about nineteen percent of NZ's carbon dioxide emissions. By adopting carbon-neutral liquid fuels across NZ's transport system, we can maintain the growth in our transport infrastructure without changing the nature of our commercial vehicle fleet. (Though diesel cars will probably displace petrol ones).
The technology exists. A sustained engineering effort is all that's needed to make it happen. We don't have to invent anything.
It will create opportunities for businesses of all sizes in a range of sectors, including all forms of primary industry. Any business that handles new or used biomass can get involved. The possibilities are limitless. We might even end up turning demolition timber into diesel and jet fuel!
I suspect our future transport system will depend on synthetic diesel and jet fuel. They'll be drop-in repacements for fossil diesel and kerosene (jet fuel). They'll actually be better than our existing fuels, because they won't have nasty ingredients such as aromatic hydrocarbons.
The most promising manufacturing technique is the well-proven Fischer-Tropsch synthesis process. This produces very high quality synthetic petroleum, which is then converted into diesel and jet fuel by normal refinery processes. This general concept is known as biomass-to-liquid or BTL. BTL diesel has been called second generation biodiesel which is very confusing because it's chemically quite different to real biodiesel. F-T diesel is a mix of hydrocarbons, whereas biodiesel is a mix of fatty acid alkyl esters. This year's Le Mans 24 hours race was dominated by diesel sportscars running F-T diesel. Most of it was made from natural gas, but the fuel supplier added some BTL diesel. As you might expect, the day after the checkered flag dropped on the 2008 Le Mans 24hours, they ran advertisements in our local newspapers telling us they "are embarking on a new era of motoring".
We already knew that.
There are lots of ways of converting raw biomass into a suitable feedstock for the F-T process. This will be the interesting part. I know about four different processes that ought to work, of which at least one is nearing commercial-scale production. Whichever process is used, the aim is to convert the biomass to a mix of carbon monoxide and hydrogen, which is the proper "feedstock" or raw material for the Fischer-Tropsch process. That's why it's sometimes called biomass gasification and Fisher-Tropsch synthesis, or BGFT.
There are other processes that might be more economic than F-T, but right now, the F-T process is responsible for by far the largest share of synthetic diesel and jet fuel production, which is why I think it's a useful benchmark for comparing biofuel processes. If a process can produce a higher yield of better fuel, at comparable or lower cost, than BGFT, it's worth looking at.
We know that F-T synthetic diesel and jet fuel work, and that they can easily meet the relevant specifications. We know how to make F-T synthetic petroleum from coal and from natural gas. Making it out of biomass, however, is relatively new. The most advanced BGFT factory is Choren Industries' 15,000 tonne/year (18 million litres/year) pilot plant in Freiberg, Germany, which is now being commissioned.
As far as I can tell, NZ can easily grow enough fresh biomass to supply its transportation fuel requirements using one of these biomass to liquid processes. We wouldn't actually need to grow all of the feedstock, because we can use these processes to make rubbish into diesel and jet fuel. This means I'm being conservative when I say that we shouldn't have to worry about fuel shortages for a very long time. That's excellent news, because F-T synthetic diesel is about the best diesel you can get.
In March 2007, I summarised my views on synthetic diesel in a submission about NZ's draft energy strategy. In early 2008, Scion published a paper which reinforced my position.
Here is my 2007 paper.
If you want to find out more, email me at 
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