Life cycle costing of waste management systems: Overview, calculation principles and case studies

摘要

This paper provides a detailed and comprehensive cost model for the economic assessment of solid waste management systems. The model was based on the principles of Life Cycle Costing (LCC) and followed a bottom-up calculation approach providing detailed cost items for all key technologies within modern waste systems. All technologies were defined per tonne of waste input, and each cost item within a technology was characterised by both a technical and an economic parameter (for example amount and cost of fuel related to waste collection), to ensure transparency, applicability and reproducibility. Cost items were classified as: (1) budget costs, (2) transfers (for example taxes, subsidies and fees) and (3) externality costs (for example damage or abatement costs related to emissions and disamenities). Technology costs were obtained as the sum of all cost items (of the same type) within a specific technology, while scenario costs were the sum of all technologies involved in a scenario. The cost model allows for the completion of three types of LCC: a Conventional LCC, for the assessment of financial costs, an Environmental LCC, for the assessment of financial costs whose results are complemented by a Life Cycle Assessment (LCA) for the same system, and a Societal LCC, for socio-economic assessments. Conventional and Environmental LCCs includes budget costs and transfers, while Societal LCCs includes budget and externality costs. Critical aspects were found in the existing literature regarding the cost assessment of waste management, namely system boundary equivalency, accounting for temporally distributed emissions and impacts, inclusions of transfers, the internalisation of environmental impacts and the coverage of shadow prices, and there was also significant confusion regarding terminology. The presented cost model was implemented in two case study scenarios assessing the costs involved in the source segregation of organic waste from 100,000 Danish households and the subsequent co-digestion of organic waste with animal manure. Overall, source segregation resulted in higher financial costs than the alternative of incinerating the organic waste with the residual waste: 1.6 Me/year, of which 0.9 M€/year was costs for extra bins and bags used by the households, 1.0 Me/year for extra collections and -0.3 Me/year saved on incineration.