New Zealand needs to wake up to bioenergy's potential

Photo / Alan Gibson

This post originally appeared on Sciblogs.co.nz.

Because our brains are controlled by history and habit, we tend to think about things the way we thought about them yesterday.

It means we're missing the opportunity for bioenergy, says Brian Cox.

The executive officer of the Bioenergy Association of New Zealand is passionate about how we could use what now is simply wasted, as well as bits of surplus land which can be used to grow sources of energy in different forms.

It should be noted that Cox is no green-tinged, environmentally and economically unrealistic airhead. Wearing his other daytime hat, he's the director of East Harbour Energy, a consulting business with a strong strategic emphasis, and the nous to crunch pragmatic numbers.

In the first instance Cox is talking about forestry waste, in the second the ability to grow short rotation energy crops such as Miscanthus (a kind of tall grass to you and me).

To this end, the association has produced a remarkably readable 'New Zealand Bioenergy Strategy', which lays out how we can get from now to its vision:

'Economic growth and employment built on New Zealand's capability and expertise in forestry, wood processing and bioenergy production - leading to new business opportunities which by 2040 supply more than 25 per cent of the country's energy needs, including 30 per cent of the country's transport fuels.'

But let's back up a step or two.

The first thing we need to do is change our way of thinking (a paradigm shift, even!).

Take the quantity of forestry production that doesn't produce a log - commonly 20 per cent of the total.

Viewed as a broader biomass resource and understanding its science, under different pressures and temperatures it can be utilised for its solid, liquid or gas components (and sometimes a combination of them).

As wood chips, or reformed into wood pellets (which also utilises sawdust), there are opportunities to burn them directly for heat. Cox envisages wood chips or pellets replacing coal in furnaces (already happening in a number of 'informed' locations throughout the country).

The same chips or pellets can also be heated in a gasifier (retrofitted to an existing gas boiler) and their heat potential used in this way.

Looking at the extraction of lignin and zylose in addition to logs and lumber makes pine trees extremely valuable. The resulting cellulose residues can then be converted to ethanol or biodiesel - and their application here is something that really needs thinking about says Cox.

As a transport fuel, using what is now wasted, producing 30 per cent of the country's transport fuel is a quite an achievable target (in fact it is well under what is possible but Cox is careful not to overhype its potential).

Throwing in short rotation, annually harvested crops such as Miscanthus, or coppicing trees such as willows, (salix) or eucalyptus, and the ability for New Zealand to sustainably produce a fair percentage of its transport fuels becomes really eye-opening he says.

The commercialisation and use of lignocellulose from wood or grasses to produce biodiesel is realistically still 10-15 years away Cox says, "but we know we can do it as a number of plants are now being built around the world." One huge advantage of this advanced biodiesel is that it is exactly the same molecular structure as mineral diesel.

However, he is adamant that using long rotation forestry waste as well as short rotation crops will be necessary to make such biofuel quantities an achievable target.

"In the meantime we should be consolidating what we do now," says Cox.

The cost of manufacturing biodiesel from tallow and cooking oils by esterfication is not too far away from the cost of mineral diesel.

"For biodiesel, we already have demand outstripping supply, as we've approached a capacity issue and investment in additional plant is now necessary."

Added to this is that the grants available under the government's Biodiesel Grants Scheme (which bridge the gap between the cost of production and market price) stop in 2012.

"All that we've gained so far could be lost, we'll be back to square one," he says. "At about 180 cents a litre, we may not need the grants, but we're still pushing the government not to have a stop/go approach as we transition to that price threshold. At the rate that the price of mineral diesel is ramping up that threshold is likely to be reached within the next three years."

Cox says that Auckland company Ecodiesel has a three-quarters built plant to make biodiesel from tallow, but this is mothballed as investors need the confidence of the grants being available beyond 2012. Commissioning that plant could allow current unsatisfied demand to be met and so assist consolidate vehicle owners experience of using biodiesel ahead of the production of significant volumes of advanced biofuels from wood and grasses in the coming years. .

As somewhat of an evangelist for biofuels, Cox says there are individual and country benefits that can be gained from and investing in plant to use to use forestry waste, as well as specialist short rotation crops to produce direct heat and transport fuels, as well as valuable liquid and gas biochemical products.

"But let's start doing it now," he says.

"Beginning the process in 10 or 15 years will be too late, and a total waste of a resource that we currently, literally, throw away."

Peter Kerr is a journalist, writer and consultant in the innovation space. View his work and that of 35 other scientists and science writers at Sciblogs, New Zealand's largest science blogging network.