New Zealand has jumped in boots and all replacing high carbon emitting coal boilers with cleaner ones powered by wood pellets.
A renewable energy expert says pellets depend on the felling of pine trees every 20 to 30 years. Photo: 123RF
Hospitals, schools and our second biggest carbon emitter Fonterra were making the switch to put a dent in our carbon emissions from coal, which last year stood at roughly two million tonnes.
But some were labelling wood pellets as a backwards move, that would slow down our progress on becoming carbon neutral by 2050.
Renewable energy expert professor Andrew Blakers from the Australian National University, described them as an expensive detour on the road to a clean energy future.
He said using electricity was a much cleaner option and that in Australia it was becoming so cheap, that in a few years it would replace gas as the go to for large industrial boilers.
This was mostly down to renewable generation such as solar and wind, with Australia now building more renewable generation per capita than anywhere in the world.
And professor Blakers had this message for the likes of Fonterra and its boilers.
"You're better off I think leaving it as coal or gas until you can get yourself organised to put an electric driven heat pump in instead. That is the way to go. Not step back to the 19th Century."
He said another problem with wood pellets was they depended on the felling of pine trees every 20 to 30 years.
A much larger amount of carbon would be soaked up if that same land was instead planted in natives and left alone.
"Wood pellets are a very bad way to allegedly reduce your carbon footprint. If the forests are being used for wood pellets, you're better off to convert that area of land to native forests, let it soak up carbon for the next 200 years and get up to 250 tons per hectare of carbon."
This was up to five times as much carbon as that soaked up by a pine plantation harvested every two decades, he said.
However Massey University's professor emeritus Ralph Sims, who was a regular contributor to the International Panel on Climate Change, said wood pellets did have a role, especially at filling the gap between now and when cheap renewable energy became available.
"High temperature heat can be produced by electro thermal technologies, but they tend to be a bit expensive at the moment, but that's an alternative. But if we've got a waste product, like our forest residues lying on the ground as an energy source which is storable, then why not collect it and use it."
However Ralph Sims said wood pellets were only a good idea if they were made from wood waste, not, as was happening in North America, whole trees, which were turned in to pellets and exported to Europe.
"That's the worst thing possible is deforestation of any forest whether it's in New Zealand, North Carolina, or the Amazon or Indonesia. We don't want to touch those forests. We want to encourage their survival and enhance their growth if that's possible, as well."
Fonterra's chief operating officer Fraser Whineray said the company was determined to reduce its use of coal, currently standing at up to 500,000 tonnes a year, to zero by 2037 and that this would be done using waste wood from the forestry sector.
"It's just simply, what do we think is going to be best to deliver reliable, renewable and cost effective energy. But that electricity price to be competitive against what was effectively a waste product, electricity has to come down quite a way to beat it, to be competitive."
Whineray said one plant had already been converted from coal to wood pellets and another new biomass boiler was already underway.
He said the timeframe for when the remaining eight plants would stop burning coal depended on how quickly the supply of wood waste could be made available and resource consents for the new boilers.
