The carbon footprint of sugar

Climate change is rapidly becoming a serious issue and one which will increasingly demand the attention of sugar producers. Estimation of the greenhouse gas emissions in the production of sugar, otherwise known as the carbon footprint, is an essential part of any sustainability study. A method of estimating net energy usage and greenhouse gas emissions has been developed, based initially on work done on biofuels. The calculation routine was developed for use in the Better Sugarcane Initiative standards, which focus on the sustainability of the sugarcane industry. This estimation procedure estimates primary energy requirements including both direct effects, mainly energy usage, and indirect effects, which include energy used in the production of fuels, fertilizers and chemicals. Allowance is also made for the inclusion of direct land use change effects. The estimation procedure allows for the production of molasses and/or ethanol, and for the export of power. Attention is given to the potential errors and problems in arriving at these estimates. The main problems are uncertainties in emissions from fertilizer use and the way in which emissions are allocated to co-products. The results show that the carbon footprint is most affected by sugarcane yield, sugar recovery, fertilizer usage, irrigation, cane burning and power export. A factory set up efficiently for maximum power generation can show a negative carbon footprint and, in this respect, maximum export of electric power can deliver a lower carbon footprint than maximum ethanol production. The calculation routine estimates the greenhouse gas emissions from field to factory gate and can be used for an existing operation or in the design of a new project to assist in making good sustainability choices.