Sustainable energy transition toward renewable energies in the New Zealand dairy industry: An environmental life cycle assessment

The dairy processing industry is considered as energy-intensive processes between New Zealand industries that use fossil fuels as a primary energy source which results in greenhouse gas emissions as well as raising other environmental impacts. To mitigate the environmental impacts of fossil fuels that are used in dairy processing plants, it is essential to design a pathway moving from fossil-based energies towards renewable energy sources in a transition period. To do so, Life Cycle Assessment (LCA), as a standardised approach, has been implemented to quantify the environmental profile of different products by evaluating the environmental impacts of product systems. In this paper, three impact categories are considered adopting accessible inventory databases that match the regional and local data along with ReCiPe as the life cycle impact assessment method. These impact categories are 1) human health; 2) ecosystem; and 3) resources. Each category contains subcategories; seven different-statistically discernible energy mix scenarios (moving from coal through natural gas towards biomass) assisted by Monte Carlo simulation are defined to assess environmental impacts. Furthermore, Cumulative Exergy Demand (CExD) as an aggregated criterion has been exploited to indicate the sustainability of the whole system. Results show that for a cheese production process a biomass based scenario has the lowest environmental burden impact in 13 impact categories out of 14 studied impacts. Indeed, it has the lowest CExD with 1.05x10-5 MJ-Eq while surprisingly natural gas based scenario has the highest environmental burden with CExD of 3.85x10-1 MJ-Eq followed by coal with 4.73x10-4 MJ-Eq