Why using wood pellets is better than burning fossil fuels

Why using wood pellets is better than burning fossil fuels

One of the best modern alternatives to gas, oil and coal fired central heating and hot water systems are wood pellet or biomass boilers. A pellet boiler is a long-term, sustainable heating method because wood pellets are a renewable, natural and ultra-low carbon fuel.

Carbon neutral fuel

Wood pellets are accounted as carbon neutral under GHG emissions rules because when burnt they emit the same amount of carbon as the tree absorbs in its lifetime.  Burning wood pellets means we are utilising carbon from the “current account” of carbon dioxide that is naturally circulating in the atmosphere, rather than using carbon from the “long term savings account” of carbon that was buried millions of years ago and formed fossil fuels.

This is difference of the source of the carbon is essential to understand the sustainability benefits of wood pellets and all biomass fuels.  The fuels are utilising solar energy, stored as carbon in the mass of the tree and working within the living carbon cycle that is essential to all life on earth.  The use of biomass fuel, as long as it does NOT result in trees or plants being cut down and not replanted (net loss), is one of the critical tools (amongst many, including greater energy efficiency, heat pumps, renewable electricity, etc.) for delivering our current and future energy requirements within the carbon cycle, instead of emitting more stored carbon from fossil fuels. 

Reusing wood waste

In New Zealand, we have a very strong, sustainably managed pine forestry industry. This means that forests are planted, harvested and then planted again in a continuous cycle. We are not cutting down native forests to harvest timber. However, the timber manufacturing industry does produce some waste products including wood shavings, sawdust and off-cuts. Often this wood waste is sent to landfill where it rots to produce methane and all the heat energy in the wood is wasted.

A much more sustainable solution is to turn the wood shavings, sawdust and off-cuts into wood pellet fuel. In plants around the country this otherwise wasted material is screened, ground and dried then pelletised by passing it through a cutter (much like an old fashioned mincer!) at high pressure. The whole process releases naturally occurring lignin, which binds the pellets and gives them their shiny appearance.  No harmful glues or additives are required!

Because wood pellets are reusing wood waste, the pellet fuel has the lowest carbon footprint of any fuel available in NZ.  Even lower than our very renewable electricity grid. 

Improved energy efficiency

Because wood pellets contain much less moisture than normal firewood they burn longer, hotter and more efficiently. They are designed specifically to be used in pellet fires and boilers with an automated pellet feeding and air control system. The careful design and control of these systems equals an extremely high combustion efficiency and is the key to reducing emissions.  There is an incredibly small amount of ash produced when the fuel is burned, equal to around 5kg for every tonne of pellets!

Supply and demand

There are three major manufacturers of wood pellets in New Zealand: Azwood Energy, Natures Flame and  Niagara Wood Fuels. Over 100,000 tonnes of pellets are produced and delivered across New Zealand every year, with the quantity increasing every year. Pellet manufacturers are so confident of the long term that there are pellet fuel supply and fixed price contracts of up to 10 years. Pellets are delivered in bulk using blower trucks to commercial sites and are available in 15kg bags from retailers for householders.

In summary, there are three main reasons wood pellet fuel is better than burning fossil fuel:

  1. Wood is a 100% renewable, natural resource with sustainable harvesting
  2. Burning wood is carbon neutral, so wood pellets won’t contribute to worsening the climate crisis
  3. Wood pellets are reusing waste product from timber mills, avoiding sending waste to landfill
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