Fonterra, along with Windsor Energy, have successfully converted the 43MW Towerpak™ boiler at Te Awamutu from firing on coal to firing on wood pellets. This will eliminate an estimated 84,000 tonnes of carbon emissions per year and reduce Fonterra’s overall coal energy consumption by an expected 10%.

The boiler is now running full capacity on wood pellets only, delivering 55t/hr of superheated steam to the plant. This is a significant step for Fonterra in helping them in their targets of 30% reduction in emissions by 2030 and reaching net zero carbon emissions by 2050.

Discussions began at the end of 2018 to how Fonterra would implement such a massive conversion, and Windsor Energy engaged with Fonterra to help engineer a turnkey solution. This project was needed to be completed in stages, beginning with a desktop study to assess how the boiler could perform on this new fuel. With the positive results from the study, we could then proceed with a fuel trial. As commonly discovered at the trial stage, modifications were going to be required to the combustion system to allow the boiler to run at full capacity.

To implement the full conversion, Windsor Energy has designed, procured, installed, and commissioned the following works for plant.

Fuel handling system modifications

Enclosures were installed for weather protection on all fuel feeding and storage, so no moisture reaches the pellets. The feeding system was also optimised for this new fuel.

Combustion system modifications

For optimising conditions for complete combustion of the pellets and ensuring the boiler can still perform at its original output.

Emissions system replacement

A cyclone system and two bespoke Windsor baghouses were designed and installed to replace the existing baghouses. This new emissions equipment was designed specifically for biomass flue gases.

Ash handling system replacement

A new ash handling system was installed which integrated all the new equipment and discharged into a common reception area.

Alongside these works, hazardous zone and explosion assessments were carried out as, like Windsor Energy, Fonterra holds the upmost concern for safety and risk aversion. As a result, extra precautionary equipment was installed for fire prevention and explosion protection.

The project has run very successfully despite the impact of Covid-19 during the manufacturing and installation stages. This incurred slight delays on equipment entering the country, but with all the right precautions in place, Fonterra and Windsor Energy were able to ensure the boiler was firing on pellets before the spring milk arrived. For more information, see our downloadable case study on the project.