The FEC designed Macknade Mill Stack was commissioned in June 2014.

The stack operated effectively during the earlier steam trials, allowing adequate separation between the two feed boilers. One of the early concerns in the stack design was inadequate separation between the two feed boilers and lack of back-pressure. This concern was alleviated by computational fluid dynamic (CFD) modelling undertaken by FEC in the early stages of the project and has now been validated by the steam trials.

Conventional design methods and finite element analysis were utilised to ensure the structural integrity of the stack and also optimise the design. The structural design of the stack was a major engineering deliverable and will shortly be put to the test in the cyclone prone Ingham region.