LCA application to a paper recycling plant: the effects of energy supply source

The main aim of this study was to evaluate the environmental performances of the recycled paper production process focusing on the energy aspect. Life Cycle Assessment (LCA) methodology was applied to a paper mill, which produces packaging paper using paper and cardboard from source separation of municipal solid waste as raw materials. Two scenarios (S1 and S2) were defined in terms of energy supply source. A cogeneration system using natural gas for the combined production of thermal and electric energy was the source in S1. Italian electricity grid (using the Italian country mix) and a natural gas boiler were the separate sources for electric and thermal energy in S2. The environmental impacts were evaluated with IPCC 2013 and ReCiPe 2016 (endpoint and midpoint) methods. The results obtained with IPCC 2013 and ReCiPe 2016 endpoint showed that for both scenarios, the huge quantity energy required for the paper production process was the main cause of impacts, principally due to the use of natural gas (primarily for combustion and secondarily for production and transport). Furthermore, the results highlighted that S1 was better in environmental terms than S2 (except for Resources scarcity category). However, the country mix considered for the electricity production could be a key factor that can influence the results. The outcomes obtained with ReCiPe 2016 midpoint pointed out several environmental aspects, which could not be appreciated with both endpoint analysis and IPCC. Therefore, choosing only the endpoint approach, or an evaluation method that considers only one impact category, can bring the risk of losing important environmental information.