Emergy-based Ecological Economic Evaluation of Beijing Urban Ecosystem

AbstractThis emergy-based urban economic account provided a historical portrait of the urban economy and its structures to understand the overload of the biosphere‘s assimilative capacity. The basic situation of the urban economy, involving the indigenous resources base, emergy consumption patterns, emergy exports and imports, was investigated, accounted and discussed. Using a series of ratios and indices arising from emergy analysis, including emergy intensity, environmental load ratio and environmental sustainability, this paper analyzed the economic development in Beijing during the years of 1999 to 2006 and the heavy pressure it has put on the environment. Results showed that the development of economy in Beijing was closely correlated with the consumption of the non-renewable resources and it was exerting rising loads on the environment. Of the total emergy use by the economic system, the imported non-renewable resources from other provinces contributed most with increasing use from imported nonrenewable resources. Emergy intensity kept rising during the periods, with the increase of the environmental loads. The pressure of environmental protection, which was caused by the over-heated investments in Beijing, could be released after the completion of the infrastructure construction. On the whole, the results of this paper outlined a frame of reference towards how the urban metabolic analysis could drive the economic policies and sustainability

A Predictive Analysis of China's Energy Security Based on Supply Chain Theory

AbstractChina's energy dependence on energy supply chain have been increasing rapidly in recent years. The long-term energy supply plays an important role to guarantee the energy security. Therefore, our emphasis placed on energy supply chain predictive analysis and security evaluation in China. In this study, a linked MARKAL-CGE-EIA model system is proposed to simulate the macro-level energy technology, macro-level economy and environmental impacts of China. The CGE module is used to produce a multi-sector simulation of economic growth and industrial structure change. A MARKAL module is used to analyze particular technologies within the energy system, given estimates of associated energy demand and the relative prices of fuel and other inputs. A third module of Environmental Impact is applied to make an analysis of pollutant emissions. The energy indicators are used to perform an assessment of the dynamic behavior and security trends of a national energy system's trajectory from 2000 to 2050. The results of our study will enable energy policy planners to understand these inter-linkages by addressing energy early-warming indicators and scenarios to the aggregate industrial sectors, the energy technology details, and environmental impacts

Physical constraints on global social-ecological energy system

Energy is the main driver of human Social-Ecological System (SES) dynamics. Collective energy properties of human SES can be described applying the principles of statistical mechanics: (i) energy consumption repartition; (ii) efficiency; (iii) performance, as efficient power, in relation to the least-action principle. International Energy Agency data are analyzed through the lens of such principles. Declining physical efficiency and growth of power losses emerge from our analysis. Losses mainly depend on intermediate system outputs and non-energy final output. Energy performance at Country level also depends on efficient power consumption. Better and worse performing Countries are identified accordingly. Five policy-relevant areas are identified in relation to the physical principles introduced in this paper: Improve efficiency; Decouple economic growth from environmental degradation; Focus on high value added and labor-intensive sectors; Rationalize inefficient fossil fuel subsidies that encourage wasteful consumption; Upgrade the technological capabilities. Coherently with our findings, policies should support the following actions: (1) redefine sectoral energy distribution shares; (2) Improve Country-level performance, if needed; (3) Reduce intermediate outputs and non-energy final output; (4) Reduce resources supply to improve eco-efficiency together with system performance

Assessment of Urban Transportation Metabolism from Life Cycle Perspective: A Multi-method Study

Abstract The goal of this study is to provide a multi-method based on the eco-thermodynamic framework to examine the environmental sustainability of urban public transportation systems. Urban transportation metabolism (UTM), as a metaphor of urban systematic research methodology for transportation system, has been proposed and combined with life cycle assessment (LCA). Results show that the most important factors in assessing the acceptability of a transportation system are not only the direct fuel consumption, and the energy and material costs of the vehicles, but also the energy and materials costs for the upstream and downstream side of the infrastructure construction and vehicle fuel

On the systemic features of urban systems. A look at material flows and cultural dimensions to address post-growth resilience and sustainability.

Urbanisation is widely recognised as a relentless trend at the global level. Nevertheless, a comprehensive assessment of urban systems able to address the future growth and decline of cities is still lacking. Urban systems today rely on abundant resources, flowing in from other regions, and their future availability and accessibility should be taken into consideration to ensure urban wellbeing and resilience in likely post-growth scenarios. A logical framework to address the challenge of urban planning and management to promote long-term urban system sustainability is proposed. Systems thinking and diagramming are applied, while comprehensively tracking the key material flows upon which cities depend back to their sources. First, the nexus among resources and urban activities is identified, and then its circularity is framed within a wider discourse on urban sustainability and resilience. Discussion is carried out within a two-fold perspective of both existing and newly built environments, while related economies are analysed in order to find possible gamechanging scenarios

Power generation from slaughterhouse waste materials : an emergy accounting assessment

Unidad de excelencia María de Maeztu MdM-2015-0552The linear path "extraction-production-consumption-waste", imposed by humans to natural ecosystems, where all material flows are instead circular, has become unsustainable. Understanding the potential value of some of these "by-products", in order to exploit them effectively in a biorefinery perspective, may help overcoming resource shortages and decrease environmental impacts. This study investigates energy and resource restoration from animal by-products. The slaughterhouse waste undergoes a rendering process to separate residual meal and fat. The latter is combusted in a co-generation plant to produce electricity and heat. The process is carefully assessed using Emergy Accounting approach with the aim of evaluating benefits and environmental load of the process considering the advantages achieved compared with the demand for ecosystem services and natural capital depletion. Moreover, the case aims at exploring three different methodological assumptions referring to the upstream burdens carried by the waste management system, proposing a modified exergy-based allocation rule. The electricity generated shows performances in terms of Unit Emergy Values ranging between 2.7E+05 sej/J, 2.2E+06 sej/J and 3.1E+07 sej/J among the different cases investigated, comparable to power from fossil fuels and renewables sources, and it provides an environmentally sound alternative to conventional waste disposal

Analysis of CO2 Emission for the Cement Manufacturing with Alternative Raw Materials: A LCA-based Framework

AbstractThe cement industry is a significant CO2 emitter mainly due to the calcinations of raw materials and the combustions of fuels. Some measures have been considered to reduce the CO2 emissions in cement industry, of which alternative raw materials are the most efficient practicing way. In this study, a LCA-based CO2 accounting framework with alternative raw materials was constructed to analyze the CO2 emissions from concrete with different kinds of low carbon substitution, within which cement production process was divided into six stages associated with the environmental impacts. A better routine is expected to understand the environmental hazards of cement products and to optimize the design to reduce adverse environmental impacts

Exploring Avoided Environmental Impacts as Well as Energy and Resource Recovery from Microbial Desalination Cell Treatment of Brine

Seawater represents a potential resource to ensure sustainable availability of water for population and irrigation purpose, especially in some areas of the world. Desalination processes allow the production of fresh water, but they generate also brine as waste product. Sustainable brine man-agement should be identified to ensure proper disposal, and potentially resource recovery. This ex-perimental study shows that emerging technologies such as Microbial Desalination Cells (MDCs) may provide a valuable contribution to the sustainability of seawater desalination sector. In this paper, we report results on lab-scale desalination brine treatments applying MDCs – which allow energy savings, resource recovery, environmental impact minimization, and reduction of the or-ganic load in municipal wastewater. Our results show that MDCs treatment allows the removal of approximately 33 g of salts (62% of the total) – including chlorides, bromides, and sulphates – from 20 mL of brine within 96 hours. The MDCs, according to the source of energy and the presence of mature biofilm at the anode, spent 7.2 J, 7.9 J and 9.6 J in the desalination process, with the higher amount of energy required by the abiotic system and the lesser by the MDCs fed with just wastewater. Our approach also shows environmental and energy reductions because of potential metal recovery instead of returning them into marine environment. We quantify the avoided life cy-cle human and marine eco-toxicity impacts as well as the reduction of cumulative energy demand of recovered metals. The main benefit in terms of avoided toxicity would arise from the mercury and copper recovery, while potential economic advantages would derive from the recovered cobalt that represents a strategic resource for many products such as battery storage systems