In recent years, several researchers have studied the potential use of ammonia (NH3) as an energy vector, focused on the techno-economic advantages and challenges for full global deployment. The use of ammonia as fuel is seen as a strategy to support decarbonization; however, to confirm the sustainability of the shift to ammonia as fuel in thermal engines, a study of the environmental profile is needed. This paper aims to assess the environmental life cycle impacts of ammonia-based electricity generated in a combined heat and power cycle for different ammonia production pathways. A cradle-to-gate assessment was developed for both ammonia production and ammonia-based electricity generation. The results show that electrolysis-based ammonia from renewable and nuclear energy have a better profile in terms of global warming potential (0.09–0.70 t CO2-eq/t NH3), fossil depletion potential (3.62–213.56 kg oil-eq/t NH3), and ozone depletion potential (0.001–0.082 g CFC-11-eq/t NH3). In addition, surplus heat for district or industrial applications offsets some of the environmental burden, such as a more than 29% reduction in carbon footprint. In general, ammonia-based combined heat and power production presents a favorable environmental profile, for example, the carbon footprint ranges from −0.480 to 0.003 kg CO2-eq/kWh.
Global warming is the greatest environmental challenge that humanity is phasing. Water availability and biodiversity are also important issues of concern. Efforts towards achieving a sustainable path are required in all major sectors. The construction and infrastructure sector is an important contributor to global resource depletion and environmental impact. Life cycle assessment (LCA) is a frequently used tool to assess the potential environmental impact of a product or service throughout its life cycle. The life cycle of a product involves the extraction of raw materials, processing, production, use, and end-of-life. The environmental performance is quantified according to several impact categories such as: global warming, abiotic depletion, acidification, eutrophication, ozone layer depletion, photochemical oxidation, among others. LCA has been applied with success in the construction and infrastructure sector, in particular for buildings of all types. Literature in LCA of buildings use a variety of methodological approaches. The objective of this literature review is to identify and compare the different methodological approaches used in LCA of residential buildings, with a particular focus on functional unit, system boundaries, environmental impact categories, and data quality. The review indicates that there are different approaches used depending on the objective of each particular study.
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