Exergy-based natural resource accounting in sustainability assessment of agricultural production systems

Ondertitel:Exergie-gebaseerde berekening van grondstoffenverbruik binnen duurzaamheidsevaluatie van landbouwproductiesystemen

We consume global natural resource stocks at an unsustainable rate, which endangers long-term resource availability and which causes environmental pollution. Mitigating pollution and increasing resource efficiency is a major challenge in our societyU+2019s sustainable development. To measure and evaluate natural resource use of entire production chains, exergy analysis and life cycle assessment are increasingly performed. Exergy analysis, however, was primarily elaborated for the energy, chemical and metallurgical industries; it therefore needs further development to evaluate natural resource use in an agricultural context. The aims of this thesis were to further develop the exergy-based framework for its application on agricultural production systems, and to provide insight into its value by case study illustrations. In the quantification of natural resource efficiency, it is unclear today how to account for land resources, on which agriculture largely depends. The photosynthetic process is not properly addressed. Also, the ancient photosynthesis during the formation of fossil resources is currently overlooked. The methodological part of this thesis investigated how to calculate an overall resource efficiency indicator that takes these aspects into account. For two products (electricity and PVC), the bio-based alternative was compared with its fossil-based counterpart. Because many agricultural systems have been intensified to achieve a higher productivity, an overall resource footprint evaluation is highly relevant. In this thesis, natural resource use of specialized dairy farms in Flanders was studied. Feed was responsible for the majority of natural resources used throughout the production chain of milk. Because feed is also the most important cost, it plays a pivotal role in improving the economic and environmental farm performance. How farms could achieve simultaneous savings in costs and natural resource demand of feed was investigated using frontier analysis and analysis of key performance indicators that are traditionally used by farm advisors.

Jaar van publicatie:2016

Toegankelijkheid:Open