Confidential Thesis: Environmental Assessment of the Dutch Beet Sugar Production System

Abstract

The potential growth of the bio-based economy and bio-chemical industry presents an opportunity for advancement in sustainability. These industries require sugar as a bio-based feedstock, for which extensive sustainability assessments are lacking. In order to better understand the environmental implications of this segment of the bio-based economy, this thesis aims first to identify research gaps in beet sugar Life Cycle Analysis (LCA) and then to fill these gaps by carrying out an in-depth LCA. The research questions first seek to understand what previous studies conclude in terms of environmental impacts, and subsequently what the research gaps are. Following this, the main research question specifically seeks to determine the cradle-to-gate environmental impacts with a focus on the Netherlands. Analysis is carried out considering environmental effects of the final delivery of 1 ton average processed, crystallised sugar as the comparison basis – considering all stages of the production system. This is achieved first by extensive industry data collection to compile an inventory, and then by applying the ReCiPe midpoint methodology, available in SimaPro 8. Literature reviewing found not only that some industry impact data was contradictory from one source to the next, but also that sugar beet seed and its associated production and processing are generally ignored or entirely based on assumption. Remarkably, results showed that where the literature gave a climate change average value of 527 kg CO2 (eq) per ton sugar, inclusion of the carbon capture in sugar resulted in a negative contribution to climate change by absorbing ~1 ton CO2 (eq) per ton sugar produced. However, factors such as fossil depletion are largely underestimated in literature – with average values 17 times lower than calculated outcomes. On the other hand, categories such as human toxicity are on average 16 times higher in literature than in calculation. For the sake of transparency, the final results are subjected to sensitivity analysis tests against literature values. Categories climate change, freshwater eutrophication and water depletion displayed similar outcomes to the literature values, whereas fossil depletion, human toxicity and ozone depletion turned out to be considerably different – which could be explained by their wide sensitivity. Having included all stages of the production of sugar from sugar beet, it was found that the final unit process stage, sugar processing – is the largest contributor to climate change (53.8%), ozone depletion (77.6%), human toxicity (71.7%), freshwater ecotoxicity (59.7%), marine ecotoxicity (81.5%), water depletion (65.7%), and fossil depletion (75%).