Burn baby burn
Fri 4 May 2012 by Nigel Pinkerton.

As winter approaches, I begin to miss my old wood burner. Somehow heat pumps just aren’t the same, and gas is expensive if you only use it for heating. But now that I’m a city dweller, where would I get my firewood from?

Anyone who has ever walked, biked, or driven through forestry land after it has been harvested can’t help but notice that a lot gets left behind. I’m not just talking about twigs and pine needles, but piles of large branches and the tops of trees that often break off when felling.

This wood represents energy from the sun which was locked up when the trees grew. Whether the wood is burnt or allowed to break down, any carbon released will simply be reabsorbed as the next generation of trees grow.

It is not surprising that a lot of effort is already being made to recover some of this resource. But current efforts are hindered by a lack of coordination between stakeholders, and by the low wholesale price of waste wood.

Let’s start by looking at pellet fires. At present wood pellets are usually made from sawmill waste, which is relatively easy to process. But steadily rising demand for pellets has seen manufactures begin to invest in processing wood from other sources.

Running a pellet burner costs between 8c and 15c/kWh, according to Consumer New Zealand. Providing you shop around for your pellets, the cost compares favourably with heat pumps at current electricity prices. Plus you get the bonus of a real fire and the knowledge that your fuel is coming from a truly sustainable source.

According to the Energy Efficiency and Conservation Authority (EECA), waste wood from forestry is currently worth about $10 per tonne on the open market. The relatively low return explains why much of it currently gets left behind to rot. But given that pellets presently wholesale for around $500 a tonne – there is scope for waste wood prices to rise without a major impact on pellet prices.

Pellets and pellet fires remain a novelty in New Zealand homes. If their use increased then economies of scale and competition from manufactures would likely see the cost of pellets come down – even if the extra demand saw waste wood prices rise to make recovery more economic.

What about those of us who own a modern, clean burning log-burner and are prepared to collect our own fuel? If forestry owners and operators granted access to the public to collect firewood then we could heat our homes all winter for very little cost.

Some forests do grant firewood permits – but they are in the minority. The rest are reluctant to grant this permission for a variety of reasons. A big one is liability – if someone slips and breaks their leg, gets their vehicle stuck, or nicks themselves with a chainsaw the person or company who granted them permission to be there could be held responsible.

As a case study, Wellington Regional Council grants permits for firewood collection in Whakatikei, Valley View, Hukinga, Maungakotukutuku, Akatarawa Saddle, and Puketiro blocks. They deal with the safety issue by asking applicants to sign a Hazard Identification Sheet and Health and Safety Guidelines. The council charges $20 per permit – which seems quite reasonable to me – and allows access on weekends and public holidays to minimise the chance of conflicts between logging trucks and private vehicles.

If more forestry companies followed the council’s lead – urban New Zealanders would have access to another sustainable source of fuel. Fees would need to be set low enough to encourage people to actually pay them and gain access legitimately – rather than “jumping the fence”. Charging $20 per permit could equate to over $40 per tonne of waste wood on the ground – if you make the crude assumption that the average permit holder would take 500kg of wood.

It would probably take a government initiative to guarantee public access, under a set of conditions, to collect firewood in New Zealand’s forests. I am not suggesting the government force owners to give up their property rights, but rather create a framework that companies can sign up to – with then incentive of a revenue stream from permits. Landowners and forestry operators would need to be comfortable that they were not liable if accidents did happen.

Modern wood burners and pellet fires are very clean burning and effectively carbon neutral. You can even convert your car to run on wood if you’re game. There are vast bioenergy reserves going to waste on New Zealand’s forestry land. All we need to do is figure out the best way to get at this energy.

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