Geothermal Energy for Wood Pellet Manufacturing Plant 

Natures Flame operate a wood pellet manufacturing plant in Taupo utilizing waste wood from New Zealand pine. The raw material typically contains a moisture content of 50-60% and requires drying before being processed into pellets. The plant produces a premium pellet that offers an easily used renewable energy source from this waste product.


To allow the plant to achieve its maximum production capacity Natures Flame signed an agreement with Contact Energy for the purchase of up to 22MW of renewable geothermal energy. 


Dobbie has assisted both Contact Energy and Natures Flame to develop the heating plant through the design and documentation of the main heat transfer systems.

The plant consists of a single geothermal heat exchanger which transfers heat from the geothermal fluid to a closed, pressurized, medium temperature hot water loop. This loop operates at up to 180°C and transfers the energy 1.2km to the Natures Flame site. Here a second heat exchanger transfers the heat from the high-pressure secondary circuit to a lower pressure tertiary circuit that feeds the waste wood dryer.

The pellets have the potential to heat domestic, commercial and industrial plants both in NZ and offshore. Dobbie congratulate both Natures Flames and Contact Energy on the completion of this project which provides a renewable energy source using waste wood from NZ’s sustainably harvested forests with most of the energy required coming from Contact Energy’s renewable geothermal energy resource.

The plant was commissioned in November 2019 and this first stage will allow Natures Flame to increase production to 85,000 tonnes/annum. Sufficient energy is available from Contact Energy to allow expansion to 175,000 tonnes/annum in the future.

Natures Flames annual production of 85,000 tonnes of pellets could potentially offset up to 1,600 terajoules of energy that may otherwise have been produced using fossil fuels with their associated carbon emissions.
The project also has flow on benefits to the regional economy, plus supporting local employment and businesses.