Search

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jenvman.2009.08.017 Byline: Paolo Vassallo (a), Chiara Paoli (a), David R. Tilley (b), Mauro Fabiano (a) Abstract: Sustainable development of coastal zones must balance economic development that encourages human visitation from a larger population with desires that differ from the local residents with the need to maintain opportunities for the local resident society and conserve ecological capital, which may serve as the basis for residents. We present a case study in which the sustainability level of a coastal zone (Riviera del Beigua), located along the Ligurian coast of north-western Italy, was assessed through the lens of systems ecology using emergy synthesis to integrate across economic, social and environmental sub-systems. Our purposes were (1) to quantify the environmental sustainability level of this coastal zone, (2) to evaluate the role of tourism in affecting the economy, society and environment, and (3) to compare emergy synthesis to Butler's Tourism Area Life Cycle model (TALC). Results showed that 81% of the total emergy consumption in the coastal zone was derived from external sources, indicating that this tourist-heavy community was not sustainable. Tourism, as the dominant economic sub-system, consumed 42% of the total emergy budget, while local residents used the remaining 58%. The progressive stages of the TALC model were found to parallel the dynamic changes in the ratio of external emergy inputs to local emergy inputs, suggesting that emergy synthesis could be a useful tool for detecting a tourist region's TALC stage. Use of such a quantitative tool could expedite sustainability assessment to allow administrative managers to understand the complex relationship between a region's economy, environment and resident society so sound policies can be developed to improve overall sustainability. Author Affiliation: (a) Department for the Study of Territory and its Resources, University of Genoa, C.so Europa 26, 16132 Genoa, Italy (b) Department of Environmental Science and Technology, University of Maryland, 1421 An Sci./Ag. Engr. Bldg., College Park, MD 20742, USA Article History: Received 2 September 2008; Revised 6 August 2009; Accepted 31 August 2009

The treatment of wastes can be accomplished using various combinations of natural processes and human invented technologies that operate by using a variety of energy sources and natural resources. In many waste treatment systems, the waste itself is used as a main energy source to drive treatment (e.g., activated-sludge in advanced wastewater treatment). Understanding the sustainability of waste treatment systems thus requires the capability for quantitatively comparing the energy and resource inputs with the waste-derived energy inputs and effluent quality. This study applied concepts of emergy accounting to develop a treatment sustainability index (TSI). The theoretical basis of the TSI is explained and then applied to two wastewater treatment systems—an operating passive treatment system and a hypothetical active treatment system for treating mine drainage in NE Oklahoma. The TSI accounts for renewable and purchased emergy inputs, the input of emergy from the wastewater itself, and the amount of work required by the receiving environment to further treat the effluent. Unlike other emergy-based indices, the TSI explicitly accounts for the energy provided by wastes, the waste treatment efficiency and the downstream effect on the releasing pollutants into receiving environments. Since the emergy associated with the waste used during treatment was orders of magnitude larger than renewable, non-renewable or purchased inputs, the TSI clearly captured the importance of accounting for waste emergy, and was able to quantify their sustainability. The TSI offers a new way to assess the sustainability of all types of treatment systems. [ABSTRACT FROM AUTHOR]

Ethanol production from cellulosic sources such as switchgrass (Panicum virgatum L.) requires the use of natural resources, fossil fuels, electricity, and human-derived goods and services. We used emergy accounting to integrate the ultimate amount of environmental, fossil fuel, and human-derived energy required to produce ethanol from switchgrass. Emergy is the total amount of energy of one form required directly and indirectly to make another form of energy. Forty-four percent of required emergy came from the environment either directly or embodied in purchased goods, 30% came from fossil fuels either directly or embodied in purchased goods, and 25% came from human-derived services indirectly. Ethanol production per petroleum use (emergy/emergy) was 4.0-to-1 under our Baseline Scenario, but dropped to 0.5-to-1 under a scenario that assumed higher input prices, lower conversion efficiencies and less waste recycling. At least 75% of total emergy was from non-renewable sources. Energy ‘hidden’ in indirect paths such as goods and services was 65% of the total. Cellulosic-ethanol is not a primary fuel source that substitutes for petroleum because its production relies heavily on non-renewable energy and purchased inputs. It is a means for converting natural resources to liquid fuel. [Copyright &y& Elsevier]

The authors present preliminary study in pursuance of developing a flow network-based methodology of building performance evaluation, as current efficiency-centered methods do not fully account for the complex building performance in which nature, economy, and humans are inseparably involved. Based on the principle of entropy, this study defines building as a thermodynamic system that networks useful resources―energy, material and information―through close interconnection with the global environment. Measures of information content in energy-flow networking and ecological performance indicators from Shannon’s information theory, Ulanowicz’s ascendency principle, and Odum’s maximum empower principle are discussed and integratively applied to developing a generic building performance evaluation model. For the holistic indication of building sustainability, this work attempts to reconcile Ulanowicz’s and Odum’s statements about ecosystem development and also integrates e m ergy (spelled with an “ m ”) and information metrics. Environmental behaviour of the building model was tested with simulation to validate consistency with system-level principles. Results reveal that network complexity corresponds to system power and resilience ( L ) and fitness ( F ) tend to peak at an intermediate level of efficiency. This finding demonstrates applicability of Odum’s maximum power principle to building study, suggesting that increasing complexity (and power) of emergy-flow networking be a fundamental characteristic of sustainable building performance. [ABSTRACT FROM AUTHOR]

In an effort to complement energy-efficiency oriented methods of environmental building study, this research seeks to understand building as a metabolic thermodynamic network, and investigates performance and sustainability with system-level principles and biological indicators. This approach introduces two system evaluation metrics: (i) solar emjoule (sej) of emergy (spelled with an “m”) and (ii) bits of information. In this way, emergy-information indicates the intensive organization of building energy flux in association with global environment development. Findings from a comparative analysis of a net-zero energy building (NZEB) and a non-NZEB show that buildings increase network complexity, resilience, and adaptability as they reduce nonrenewable inputs with energy feedback loops. The consistent tendency of maximizing information and complexity at the expense of efficiency demonstrates that building thermodynamic networking parallels the general ecosystems developmental phenomenon –maximum power at optimal efficiency. [ABSTRACT FROM AUTHOR]

Based on emergy accounting rules, only the greater number between emergy inputs from the same source, e.g., solar radiation and rainfall, should be accounted in emergy analysis to avoid double-counting. Using a year or a season as time scale, the rainfall emergy is usually larger than that of solar energy and thus taken as the renewable emergy input to the ecosystem. However, using a day as time scale, on sunny days with no rain only the solar energy would be counted as the renewable emergy. Therefore, different time scales may affect renewable emergy accounting. In this paper, we explored the effects of four time scales (year, season, month, and day) on renewable emergy accounting of forest ecosystems in Southeast China, a humid area, and the Minqin Oasis in Northwest China, an arid area. The results show that annual renewable emergy increased with the decrease of time scale but were close to each other in Southeast China (i.e., 2.5% difference at most), but were up to 30% different in arid Northwest China. However, the water which is actually used by forests for ecological productivity is evapotranspiration (ET), which can be less than precipitation in humid areas, but higher than rainfall in arid areas where groundwater compensates. Thus, it is ET rather than the available rainfall which should be counted as the renewable emergy input to ecological productivity. Otherwise the emergy contribution of renewable natural resources to ecosystems may be overestimated or underestimated, e.g., 0.33-7.33 times to the forests in Southeast China, and 0.36 times to the oasis system in Northwest China. Furthermore, despite whether or not it rains, ET emergy is often larger than solar emergy in most cases. Therefore, the use of ET emergy not only improves the estimate of emergy input, but also helps avoid the effect of time scale on renewable emergy accounting. [ABSTRACT FROM AUTHOR]

Abstract: Derived from the maximum power principle (MPP), the maximum empower principle (MePP) is considered as the foundation of emergy theory and evaluation methods. However, it has often encountered some doubts since proposed, because of lacking sufficient empirical evidence. To test the validity of the MePP in the self-organization of forest ecosystems, this paper applied a process-based ecosystem model (Biome-BGC) to simulate the dynamics of biomass, litter and soil organic matter (SOM) of three forest plantations in south China during 1985–2007, and attempted to replicate their self-organizing processes. The simulated results and input flows were transformed to emergy as a common basis and, from the viewpoint of emergy synthesis, the dynamics of the production efficiency and empower of the three forest ecosystems were revealed along with their self-organizing developments over time. The results showed that three forest plantations had similar dynamic change patterns of emergy efficiency and empower, but the production efficiencies of them were not always consistent with their empower performances. The production efficiency firstly increased rapidly to maximums, and then decreased to optimal moderate values. However, the empower came to the maximums after the efficiency peaked and then fluctuated up and down, dependent on weather. These results implied that, a forest ecosystem in its self-organizing process tends toward maximum empower at optimal efficiency. Behind the maximum empower of the forest ecosystem is the desynchrony development of different components, e.g., biomass, litter and SOM; leaf, stem and root; biomass and biodiversity. As a whole, the MePP functions like an invisible hand controlling the general self-organizing development of forest ecosystems and pointing out the direction of their development. [Copyright &y& Elsevier]

This study evaluates the sustainability of net-zero energy building (NZEB), in terms of ecosystems development on a global environmental scale, with ecological indices and metrics. Employing Howard Odum's ecosystems theory and emergy (spelled with an “ m ”), authors attempt to associate building energy consumption with thermodynamic networking of energy quality transformation. All upstream impacts of energy use are evaluated with emergy-based sustainability indicators. A LEED-platinum credited NZEB was chosen for tests and a previous study was revisited to set a baseline (non-NZEB) with refined data for comparative analyses. Findings show that NZEB uses greater nonrenewable emergy to seek a zero-energy budget despite its greater emergy sustainability index (ESI). It was identified that production of renewable energy and the intensification of a climate-modifying function (insulation) required an increase of environmental inputs (construction materials, economic services and labor) with upgraded energy quality. Empower distributions through building components characterize spatial hierarchies of building energy flow. This work demonstrates that building sustainability tends to depend on increasing power, not efficiency, which justifies maximum empower principle in environmental building research. [ABSTRACT FROM AUTHOR]