A Life Cycle Assessment of Biomethane Production from Waste Feedstock Through Different Upgrading Technologies

Abstract

Upgrading consists of a range of purification processes aimed at increasing the methane content of biogas to reach specifications similar to natural gas. In this perspective, an environmental assessment, based on the Life Cycle Assessment (LCA) method, of different upgrading technologies is helpful to identify the environmental characteristics of biomethane and the critical steps for improvement. The aim of this work is to conduct an LCA of biomethane production from waste feedstock, using the SimaPro software. The study focuses on the comparison of several upgrading technologies (namely, membrane separation, cryogenic separation, pressure swing adsorption, chemical scrubbing, high pressure water scrubbing) and the on-site cogeneration of electricity and heat, including the environmental benefits deriving from the substitution of fossil-based products. The results show a better environmental performance of the cogeneration option in most of the impact categories. The Fossil resource scarcity is the impact category which is mainly benefited by the avoided production of natural gas, with savings of about 0.5 kg oil eq/m3 of biogas for all the investigated technologies, with an average improvement of about 76% compared to conventional cogeneration. The results show that the membrane upgrading technology is slightly more environmentally convenient than the other upgrading technologies.

Environmental-Economic Assessment of the Pressure Swing Adsorption Biogas Upgrading Technology

“…Bioenergy, and the anaerobic digestion within it, are important constituents of a sustainable energy mix in Europe [3,4]. Anaerobic digestion is a complex bio-chemical transformation process mainly under anaerobic conditions done by a mixture of aerobic and anaerobic microorganisms, such as fermentative and methanogenic bacteria, and produces biogas [5,6]. Biogas, usually having a variable composition of CH 4 and CO 2 35-70% and 15-40%, respectively [4,7], can be used in versatile ways having less problems of use, such as low energy density, emissions, and corrosion when upgraded, and performs similar characteristics as natural gas [3,4,8,9].…”

“…Between 2011 and 2017, biogas production in the EU increased from 123,526 to 195,684 GWh [10]. Although the majority of biogas is used for electricity (62%) and heat (27%) production [5,11], the amount of upgraded biogas grew from 752 to 22,048 GWh [12]. This is almost a thirtyfold growth that indicates a shift of the business model of biogas plants, from electricity and heat production to upgrading biogas to biomethane [3].…”

“…Life-cycle assessment (LCA) is a valuable tool that is often used to analyze evolving technologies and their bottlenecks creating more sustainable ways. Studies assessing sustainability of biogas upgrading technologies are not just limited in number [4,5,7,9,19,[22][23][24], but they also differ in terms of the evaluated technology, scope, applied data base, functional unit (FU), and characterization model, which hinder comparison and further analysis. In addition, many studies consider only major operational energy and material consumption and base their calculations on literature or modeling data.…”

Environmental Decision Support System for Biogas Upgrading to Feasible Fuel

“…Biogas is generated from the anaerobic digestion of sewage sludge in wastewater treatment plants, the organic fraction from municipal solid wastes, livestock residues or organic agroindustry wastes [3][4][5]. The major component of biogas is methane (50-70%) and its content determines the energetic value of the biogas produced.…”

Limiting factors for biogas production from cow manure: energo-environmental approach

“…Today, despite the ever-increasing environmental concerns over the dependency on non-renewable energy resources, the major global energy systems still depend on fossil fuels (Florio et al, 2019;Lim & Biswas, 2019;Nosratabadi et al, 2019;Sharma, Ansari, Pal, Singh, & Lalhriatpuia, 2019;Škapa & Vochozka, 2019;Tabesh, Feizee Masooleh, Roghani, & Motevallian, 2019;Torabi, Hashemi, Saybani, Shamshirband, & Mosavi, 2019). However, because of environmental concerns, the world is shifting towards renewable energy resources (Afsharzade et al, 2016;Baena-Moreno et al, 2019;Eder & Mahlberg, 2018;Lyytimäki, 2018;Nethengwe, Uhunamure, & Tinarwo, 2018;Rosa et al, 2018;Vochozka, Maroušková, & Šuleř, 2018).…”