Low-grade wood potential as energy source

The potential to use more Central Otago and Lakes District trees for heating needs to be explored in greater depth according to Queenstown Lakes District Council forester Briana Pringle.

Ms Pringle said that a report released this week, ''The feasibility of developing a wood energy industry across Central Otago'', identified opportunities to develop better uses for low-value wood from the region's forests and she believed the key was likely to be growth in demand.

''We could sustainably utilise these low-grade products in a wood energy industry locally ... if the industry was to grow.''

Ms Pringle said the report listed nine schools and commercial businesses where converting to boilers fired by woodchips could be an option before 2017.

''The report finds that an opportunity exists for the Queenstown and Central Otago districts to provide a significant proportion of their industries' energy requirements using locally owned and sourced wood fuels as a renewable fuel resource,'' Ms Pringle said.

She pointed out the cost of delivered wood fuel was reported as being ''very favourable'' at 4.5-6.5c/kWh when compared to diesel (17-19c/kWh) or lpg (12-14c/kWh).

She believed establishing an ''energy hub'', or cluster of local businesses supplying and using wood energy, could help promote growth, as had been the case in Dunedin.

''Investment in a wood fuel hub for an existing player would be feasible providing there is demand.''

The report suggested the ''most feasible'' way of using log residue from the Queenstown area was for an existing wood-energy supplier to establish a central processing yard between Queenstown and Cromwell and use their existing equipment ''as and when required''.

Ms Pringle said wood-energy suppliers working in other parts of the province had portable equipment that could be used.

Ms Pringle said such an operation would enable the use of some wilding forest, ''especially in areas where high-value log products can also be extracted as part of the process.

''Mature wilding forests have a higher level of low-value wood product - when compared to plantation forests - which could be utilised as a wood fuel.''

The report considered a new ''greenfields'' wood-energy processing business in the Queenstown region would not be viable because of insufficient log residue.

It also said chipping trees for energy was not an economic way of getting rid of the region's wilding conifers because many were too small.

- mark.price@odt.co.nz

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