Integrating waste thermal conversion and lifecycle analysis for sustainable energy production: Reflecting upon environmental and economic impacts

Aiming at a society that thrives within the sustainable development model, managing waste is a critical challenge and a huge opportunity. Unlike traditional landfilling, which stands as the least advisable practice in the waste hierarchy, the purpose of waste-to-energy techniques is to recover the energy embedded within waste, transforming it into valuable resources. This research analyses various biomass and solid waste samples collected worldwide to elucidate their properties and applications, correlating them with the suitability of different treatment and valorization techniques. A case study is presented for municipal solid waste, the environmental and cost analysis of three techniques being discussed. The impacts of emitted chemicals and pollutants, saved resources and avoided emissions were explained, while costs were compared to the use of electricity from the national supply mix. Incineration has shown higher impacts than gasification schemes for global warming potential, marine and human toxicity, and lower in eutrophication, abiotic depletion and terrestrial toxicity. All techniques depicted credits for acidification, ozone depletion and photochemical oxidation potential, mostly ruled by NOx, SO₂, R114, inorganic CO and non-methane volatile organic compound emissions. Paradigmatically, the economic perspective shows that incineration presents lower costs than that of purchasing energy from the national grid. This study underscores the importance of tailored strategies for specific characteristics of regional waste, taking into consideration the different applicability of each technique. As future directions, this study shows the trade-offs for broader applicability of techniques that so far are not yet as widely implemented.