From sugar mill to biorefinery: Global warming potential of upgrading a centenary factory

An overall increase of Global Warming Potential was observed by the change of the Mossman sugar mill into a Biorefinery.

The report was published in the International Sugar Journal in October 2018. 

Researchers from the University of Queensland and Usina La Florida, Compania Azucarera Los Blacanes, Argentinia, have written a scoping review of the Global Warming Potential (GWP) of a multi-purpose sugarcane biorefinery based on the Life Cycle Assessment (LCA).

They used the Mossman sugar mill as an example.

Life Cycle Assessment is a technique to assess environmental impacts associated with all the stages of a product's life from raw material extraction through materials processing, manufacture, distribution, use, repair and maintenance, and disposal or recycling. 

The researches looked at four different scenarios:
S1: the baseline scenario - using the current production system, which produces sugarcane, sugar, molasses and electricity.
S2: addition of industrial units to produce ethanol from molasses.
S3: addition of industrial units to produce single-cell protein (SCP) from vinasse.
S4: addition of industrial units to produce bio-naphtha/electricity from crop residue.

The accumulative Global Warming Potential (GWP) of sugarcane production was the highest, followed by sugar and bio-naphtha.

S2 reduced the Global Warming Potential by 1.7% compared with S1.
S3 increased its total Global Warming Potential by by 30%.
S4 increased its total Global Warming Potential by 86% 

The authors observed an overall increase of Global Warming Potential by the change of a traditional sugar mill into a Biorefinery.

They also concluded that most of the Green House Gases (GHG) emissions occurs during the field operations. A detailed LCA study for the transformation of Mossman sugar mill into a Biorefinery should emphasise sugarcane production, transportation, and trash collection as the major sources of GHG.