Forestry slash to biofuels

Turning wood waste into a power source may slash prices.

Brian Cox, managing director of the BioEnergy Association of New Zealand, took to controversial independent NZ media outlet The Platform this week to discuss a proposal that solves two problems in one: using forestry slash as a biofuel.

Forestry slash has caused significant problems during floods in New Zealand Aoteaora, resulting in property and infrastructure damage and the tragic death of a 12-year-old boy in recent years. While waste residue from timber processing has long been used in the industry to power kilns and other needs, it has traditionally been left behind at plantations.

Cox says that the country is overlooking it as a valuable energy resource. Rising costs – particularly for natural gas – have seen both industrial and residential power prices surge since the start of the decade.

He told interviewer Leah Panapa that the quantity of slash is obviously significant and that it is frequently available in piles by the side of accessible roads where de-limbing has been done. Noting that areas like the Central North Island already collect forest slash for use in local industrial boilers, Cox said, “We could get so much more if we had a will to pick it up.

“Energy is one of the easiest products we can make from it. We can extract chemicals and do a whole lot of other things with it, but the one that is most economical today is energy. And what do we have a problem with? Energy!”

He flagged that the missing link at the moment is creating a path from the resource to the power generators, but said that may be about to change.

“Genesis Energy at Huntly are looking at putting biomass into the Huntly Power Station instead of coal,” said Cox. “They are now talking to forest owners and farmers around the Central Plateau and Highland, around Waikato, to get contracts for enough biomass to come in. And if they do that, they won’t need to import coal.”

Cox said that slash could supply up to 27% of the nation’s energy by 2050, saying that it was already at about 9% without really trying to grow the sector. The readiness of the resource makes it even more attractive, Cox said.

Panapa asked whether the economic cost of collecting forestry slash was too high, but Cox replied that the increasingly high costs of power generation in NZ and other issues such as the natural gas shortfall and transitions from coal meant that it was already economical and that cost would improve as technologies and demand improved.

The cost of forestry slash is about NZ$16/gigajoule. By comparison, mid-2024 figures from the Electricity Authority Te Mana Hiko (the most recent data showing a like for like comparison) have gas prices above NZ$25/gj, diesel fluctuating in the NZ$40-50 range and only coal cheaper at around NZ$9, though with a significantly higher carbon cost. Figures weren’t given for renewable sources, but overall, standard electricity generation costs in recent years have been around NZ$26-30/gj.

OneFortyOne has been one of the forestry companies leading the charge in using slash as a biofuel. Last year it signed a new five-year agreement with Canterbury Woodchip Supplies to see forestry slash turned into biofuel, replacing coal in the boilers of local companies such as produce firm JS Ewers. This switch to green energy has seen JS Ewers achieve a 98% reduction in on-farm carbon dioxide emissions, a drop of 27,000 tonnes of emissions annually.

Mark Coghill, OneFortyOne operations manager, says the company has invested close to a million dollars into the biofuel project since late 2021. “Over the next five years we hope to reduce the amount of wood waste in our forests by at least 75,000 tonnes,” he said.

The move has resulted in lower fuel costs for businesses and potentially removing the need to burn 22 thousand tonnes of coal over five years, reducing carbon dioxide emissions by 50,000 tonnes.

If Cox gets his way and those figures are scaled up nation-wide, even political figures who aren’t concerned about carbon abatement can see the benefits.

MAIN PIC: Mark Coghill with some of the waste wood fibre OneFortyOne has collected for re-use as biomass. Image: courtesy OneFortyOne