Biofuel may help get us out of woods

Diesel prices could be fixed for up to 12 months in some parts of New Zealand if technology used to turn wood waste and grass into biofuels is adopted.

The technology needed to make biofuels from wood residues, grasses, and industrial waste is being commercially manufactured in the United States. If adopted here, it could offer some fuel price certainty and open up regional markets for miscanthus, a tall grass used for shade and animal bedding, and forestry industry waste, Miscanthus New Zealand says.

‘‘In regions where there is a poor market or no market at all for pulp logs and low-quality wood, production of renewable diesel can provide a very viable commercial outlet for these forest products,’’ MNZ spokesman Peter Brown said.

The renewable product made using miscanthus was a direct substitute for mineral diesel and met all New Zealand specifications other than density (kilograms per litre), says MNZ.

However, the fuel’s high energy density per kilogram meant the amount of energy per litre of fuel was equal to, and in some cases better than, that of fossil fuel diesel.

US trials had shown radiata pine material and miscanthus were suitable for use with the production technology, highlighting huge potential for the New Zealand forestry industry, and for anyone prepared to grow miscanthus on a commercial scale.

The small-scale technology uses 50,000 tonnes of dry matter per year, meaning production plants could use regionally produced wood residue and grass and the resulting renewable diesel fuel could be used regionally.

Brown said if the raw materials were supplied on a fixed contract price for 12 months and staff were employed on the same basis, renewable diesel could be provided with a 12-month fixed price.

‘‘That price can be competitive with current and recent commercial diesel prices,’’ he said.

Professor Ralph Sims, director of Massey University’s Centre for Energy Research, said biofuels would have a role to play in moving towards net zero greenhouse gas emissions globally. However, there were good and bad biofuels and where the energy crops were grown could determine which category the fuel fell into, he said.

Biofuels produced from crops grown on fertile soils in competition with food crops were ‘‘bad biofuels’’.

But if produced from purposegrown forests on marginal land, a biofuel with the same composition could fall into the ‘‘good biofuel’’ category.