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Sustainability, Volume 3, Issue 12 (December 2011), Pages 2323-2527

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Editorial

Jump to: Research, Review

Open AccessEditorial Synthesis to Special Issue on New Studies in EROI (Energy Return on Investment)
Sustainability 2011, 3(12), 2496-2499; doi:10.3390/su3122496
Received: 10 December 2011 / Accepted: 13 December 2011 / Published: 14 December 2011
Cited by 2 | PDF Full-text (196 KB) | HTML Full-text | XML Full-text
Abstract
This paper is a synthesis of a series of twenty papers on the topic of EROI, or energy return on investment. EROI is simply the energy gained from an energy-obtaining effort divided by the energy used to get that energy. For example, [...] Read more.
This paper is a synthesis of a series of twenty papers on the topic of EROI, or energy return on investment. EROI is simply the energy gained from an energy-obtaining effort divided by the energy used to get that energy. For example, one barrel of oil invested into getting oil out of the ground might return fifty, thirty, ten or one barrel, depending when and where the process is taking place. It is meant to be read in conjunction with the first paper in this special issue and also a number of the papers themselves. As such I try to summarize what general trends we might conclude from these varied and often highly technical papers. About half of the papers are reports on empirical analyses of various energy sources such as Norwegian or Gulf of Mexico oil, Pennsylvania gas and so on. About a quarter of the papers are methodological: how do we go about undertaking these analyses, what problems are there, what are the proper boundaries and so on. The final quarter are in a sense philosophical: since it appears that we will be living indefinitely in a world of decreasing EROIs, what are the economic, social and psychological implications? The rest of this paper summarizes the results of these studies. Full article
(This article belongs to the Special Issue New Studies in EROI (Energy Return on Investment))

Research

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Open AccessArticle Analysis of the Energy Return on Investment (EROI) of the Huge Daqing Oil Field in China
Sustainability 2011, 3(12), 2323-2338; doi:10.3390/su3122323
Received: 5 February 2011 / Revised: 2 August 2011 / Accepted: 28 November 2011 / Published: 30 November 2011
Cited by 9 | PDF Full-text (537 KB) | HTML Full-text | XML Full-text
Abstract
In China there has been considerable discussion of how one should express the efficiency of energy conversion and production. Energy return on investment (EROI) can be useful for this because its methodology is based on outputs and inputs. Unfortunately, similar to the [...] Read more.
In China there has been considerable discussion of how one should express the efficiency of energy conversion and production. Energy return on investment (EROI) can be useful for this because its methodology is based on outputs and inputs. Unfortunately, similar to the rest of the world, most of the data available for assessing energy gains and costs for oil and gas in China has to be derived from economic costs and revenues for oil fields. In this paper we derive a first EROI for China based on using this approach and the existing data for production of crude oil and natural gas for the Daqing oil field, the largest oil field in China. We estimate that its EROIstnd expressed as heat equivalent was 10:1 in 2001 but has declined to 6.5:1 in 2009. Based on this trend we project that the EROIstnd will decline to 4.7:1 in 2015, and the net energy from the field will be decreasing substantially. The calculations have some errors because of incomplete data, and if various externalities are taken into account, the EROI of this oil field would be lower than our present estimates. The trends of EROI and net energy suggest that the Daqing oil field will face more difficulty in the future which can not be overcome by government fiat. Full article
(This article belongs to the Special Issue New Studies in EROI (Energy Return on Investment))
Open AccessArticle Deriving an Improved Dynamic EROI to Provide Better Information for Energy Planners
Sustainability 2011, 3(12), 2339-2357; doi:10.3390/su3122339
Received: 10 January 2011 / Revised: 4 August 2011 / Accepted: 1 September 2011 / Published: 8 December 2011
Cited by 3 | PDF Full-text (221 KB) | HTML Full-text | XML Full-text
Abstract
The two most frequently quantified metrics of net energy analysis–the energy return on (energy) investment and the energy payback period–do not capture the growth rate potential of an energy supply infrastructure. This is because the analysis underlying these metrics is essentially static–all energy inputs and outputs are treated the same, regardless of where they occur in the life cycle of the infrastructure. We develop a dynamic energy analysis framework to model the growth potential of alternative electricity supply infrastructures. An additional figure of merit, the infrastructure doubling time, is introduced. This metric highlights the critical importance of the time phasing of the initial energy investment for emplacing a given infrastructure, as opposed to the ongoing O&M energy expenditures, for the infrastructure’s growth potential. The doubling time metric also captures the influence of capacity factor, licensing and construction time lags. Full article
(This article belongs to the Special Issue New Studies in EROI (Energy Return on Investment))
Open AccessArticle An Edible Energy Return on Investment (EEROI) Analysis of Wheat and Rice in Pakistan
Sustainability 2011, 3(12), 2358-2391; doi:10.3390/su3122358
Received: 31 October 2011 / Accepted: 8 November 2011 / Published: 8 December 2011
Cited by 8 | PDF Full-text (721 KB) | HTML Full-text | XML Full-text
Abstract
Agriculture is the largest sector of Pakistan’s economy, contributing almost 22% to the GDP and employing almost 45% of the total labor force. The two largest food crops, wheat and rice, contribute 3.1% and 1.4% to the GDP, respectively. The objective of [...] Read more.
Agriculture is the largest sector of Pakistan’s economy, contributing almost 22% to the GDP and employing almost 45% of the total labor force. The two largest food crops, wheat and rice, contribute 3.1% and 1.4% to the GDP, respectively. The objective of this research was to calculate the energy return on investment (EROI) of these crops on a national scale from 1999 to 2009 to understand the size of various energy inputs and to discuss their contributions to the energy output. Energy inputs accounted for within the cropping systems included seed, fertilizer, pesticide, human labor, tractor diesel, irrigation pump electricity and diesel, the transport of fertilizer and pesticide, and the embodied energy of tractors and irrigation pumps. The largest per-hectare energy inputs to wheat were nitrogen fertilizer (52.6%), seed (17.9%), and tractor diesel (9.1%). For rice, the largest per-hectare energy inputs were nitrogen fertilizer (32%), tube well diesel (19.8%), and pesticide (17.6%). The EROI of wheat showed a gradual downward trend between 2000 and 2006 of 21.3%. The trend was erratic thereafter. Overall, it ranged from 2.7 to 3.4 with an average of 2.9 over the 11-year study period. The overall trend was fairly consistent compared to that of rice which ranged between 3.1 and 4.9, and averaged 3.9. Rice’s EROI dipped sharply in 2002, was erratic, and remained below four until 2007. It rose sharply after that. As energy inputs increased, wheat outputs increased, but rice outputs decreased slightly. Rice responded to inputs with greater output and an increase in EROI. The same was not true for wheat, which showed little change in EROI in the face of increasing inputs. This suggests that additional investments of energy in rice production are not improving yields but for wheat, these investments are still generating benefits. The analysis shows quantitatively how fossil energy is a key driver of the Pakistani agricultural system as it traces direct and indirect energy inputs to two major food crops. Full article
(This article belongs to the Special Issue New Studies in EROI (Energy Return on Investment))
Open AccessArticle Environmental Assessment Methodologies for Commercial Buildings: An Elicitation Study of U.S. Building Professionals’ Beliefs on Leadership in Energy and Environmental Design (LEED)
Sustainability 2011, 3(12), 2392-2412; doi:10.3390/su3122392
Received: 6 September 2011 / Revised: 14 November 2011 / Accepted: 15 November 2011 / Published: 12 December 2011
Cited by 3 | PDF Full-text (491 KB) | HTML Full-text | XML Full-text
Abstract
Voluntary environmental programs (VEPs) have become increasingly popular around the world to address energy efficiency issues that mandatory building codes have not been able to tackle. Even though the utility of voluntary schemes is widely debated, they have become a de facto [...] Read more.
Voluntary environmental programs (VEPs) have become increasingly popular around the world to address energy efficiency issues that mandatory building codes have not been able to tackle. Even though the utility of voluntary schemes is widely debated, they have become a de facto reality for many professionals in the building and construction sector. One topic that is neglected, however, in both academic and policy discussions, relates to how professionals (architects, engineers, real estate developers, etc.) perceive the rise of voluntary rating schemes. In order to fill this gap in the literature, the present study investigates beliefs underlying adoption behavior regarding one of the most prominent voluntary assessment and certification programs in the U.S. building industry, the Leadership in Energy and Environmental Design (LEED) scheme. In this paper, an elicitation study, based on 14 semi-structured interviews with building professionals in the North East of the United States, was conducted to analyze this question. Building on the Reasoned Action Approach, this paper shows that, in addition to more conventional factors such as financial calculations and marketing aspects, the understanding of beliefs held by building professionals offers important insights into their decisions to work with Voluntary Environmental Assessment and Rating Programs. Full article
(This article belongs to the Special Issue Sustainable Building)
Open AccessArticle Implications of Energy Return on Energy Invested on Future Total Energy Demand
Sustainability 2011, 3(12), 2433-2442; doi:10.3390/su3122433
Received: 5 January 2011 / Revised: 10 July 2011 / Accepted: 10 November 2011 / Published: 13 December 2011
Cited by 4 | PDF Full-text (606 KB) | HTML Full-text | XML Full-text
Abstract
Human society is now at the beginning of a transition from fossil-fuel based primary energy sources to a mixture of renewable and nuclear based energy sources which have a lower Energy Return On Energy Invested (EROEI) than the older fossil based sources. [...] Read more.
Human society is now at the beginning of a transition from fossil-fuel based primary energy sources to a mixture of renewable and nuclear based energy sources which have a lower Energy Return On Energy Invested (EROEI) than the older fossil based sources. This paper examines the evolution of total energy demand during this transition for a highly idealized energy economy. A simple model is introduced in which the net useful energy output required to operate an economy is assumed to remain fixed while the lower EROEI source gradually replaces the older higher EROEI primary energy source following a logistics substitution model. The results show that, for fixed net useful energy output, total energy demand increases as the ratio EROEInew/EROEIold decreases; total energy demand diverges as EROEInew approaches unity, indicating that the system must collapse in this limit. Full article
(This article belongs to the Special Issue New Studies in EROI (Energy Return on Investment))
Open AccessArticle Comparing Carbon and Water Footprints for Beef Cattle Production in Southern Australia
Sustainability 2011, 3(12), 2443-2455; doi:10.3390/su3122443
Received: 22 September 2011 / Revised: 18 November 2011 / Accepted: 6 December 2011 / Published: 13 December 2011
Cited by 22 | PDF Full-text (372 KB) | HTML Full-text | XML Full-text
Abstract
Stand-alone environmental indicators based on life cycle assessment (LCA), such as the carbon footprint and water footprint, are becoming increasingly popular as a means of directing sustainable production and consumption. However, individually, these metrics violate the principle of LCA known as comprehensiveness [...] Read more.
Stand-alone environmental indicators based on life cycle assessment (LCA), such as the carbon footprint and water footprint, are becoming increasingly popular as a means of directing sustainable production and consumption. However, individually, these metrics violate the principle of LCA known as comprehensiveness and do not necessarily provide an indication of overall environmental impact. In this study, the carbon footprints for six diverse beef cattle production systems in southern Australia were calculated and found to range from 10.1 to 12.7 kg CO2e kg−1 live weight (cradle to farm gate). This compared to water footprints, which ranged from 3.3 to 221 L H2Oe kg−1 live weight. For these systems, the life cycle impacts of greenhouse gas (GHG) emissions and water use were subsequently modelled using endpoint indicators and aggregated to enable comparison. In all cases, impacts from GHG emissions were most important, representing 93 to 99% of the combined scores. As such, the industry’s existing priority of GHG emissions reduction is affirmed. In an attempt to balance the demands of comprehensiveness and simplicity, to achieve reliable public reporting of the environmental impacts of a large number of products across the economy, a multi-indicator approach based on combined midpoint and endpoint life cycle impact assessment modelling is proposed. For agri-food products, impacts from land use should also be included as tradeoffs between GHG emissions, water use and land use are common. Full article
Open AccessArticle Sustainable Micro-Manufacturing of Micro-Components via Micro Electrical Discharge Machining
Sustainability 2011, 3(12), 2456-2469; doi:10.3390/su3122456
Received: 8 October 2011 / Revised: 28 November 2011 / Accepted: 1 December 2011 / Published: 13 December 2011
Cited by 3 | PDF Full-text (810 KB) | HTML Full-text | XML Full-text
Abstract
Micro-manufacturing emerged in the last years as a new engineering area with the potential of increasing peoples’ quality of life through the production of innovative micro-devices to be used, for example, in the biomedical, micro-electronics or telecommunication sectors. The possibility to decrease [...] Read more.
Micro-manufacturing emerged in the last years as a new engineering area with the potential of increasing peoples’ quality of life through the production of innovative micro-devices to be used, for example, in the biomedical, micro-electronics or telecommunication sectors. The possibility to decrease the energy consumption makes the micro-manufacturing extremely appealing in terms of environmental protection. However, despite this common belief that the micro-scale implies a higher sustainability compared to traditional manufacturing processes, recent research shows that some factors can make micro-manufacturing processes not as sustainable as expected. In particular, the use of rare raw materials and the need of higher purity of processes, to preserve product quality and manufacturing equipment, can be a source for additional environmental burden and process costs. Consequently, research is needed to optimize micro-manufacturing processes in order to guarantee the minimum consumption of raw materials, consumables and energy. In this paper, the experimental results obtained by the micro-electrical discharge machining (micro-EDM) of micro-channels made on Ni–Cr–Mo steel is reported. The aim of such investigation is to shed a light on the relation and dependence between the material removal process, identified in the evaluation of material removal rate (MRR) and tool wear ratio (TWR), and some of the most important technological parameters (i.e., open voltage, discharge current, pulse width and frequency), in order to experimentally quantify the material waste produced and optimize the technological process in order to decrease it. Full article
(This article belongs to the Special Issue Sustainable Manufacturing)
Open AccessArticle Undergraduate Writing Promotes Student’s Understanding of International Sustainable Development in Horticulture
Sustainability 2011, 3(12), 2470-2495; doi:10.3390/su3122470
Received: 24 October 2011 / Revised: 16 November 2011 / Accepted: 18 November 2011 / Published: 14 December 2011
PDF Full-text (370 KB) | HTML Full-text | XML Full-text
Abstract
Promotion of undergraduate student thinking and learning in the realm of sustainable production is a new focus for horticulture curricula. In a writing intensive course, Greenhouse Management (Hort 3002W; University of Minnesota), students focus their learning of sustainability by writing peer-reviewed, 3-phase [...] Read more.
Promotion of undergraduate student thinking and learning in the realm of sustainable production is a new focus for horticulture curricula. In a writing intensive course, Greenhouse Management (Hort 3002W; University of Minnesota), students focus their learning of sustainability by writing peer-reviewed, 3-phase ‘Worldwide Sustainable Horticultural Crop Production Papers’ on past, present, and future prospects for sustainability. The USA is used as an in-class example throughout the semester while each student focuses their writing on a specific country of their choosing. Their papers focus on eight goals for each country across the three Phases: I—their choice of a country, definition of sustainability, identification of historical production practices, current production statistics; II—current production practices and integration of historical/current practices (ranked strategies); III—finalized sustainable development strategy, design of a future sustainable, controlled-environment production facility. The last two goals (Phase III) provide plant breeders with potential breeding objectives for country-specific cultivar development within a sustainable production framework. Completed papers are web-published for global availability to enable each country’s researchers and policy makers to access sustainable ideas for future development. In 2009–2010, ‘Worldwide Sustainable Horticultural Crop Production Papers’ were published for 41 countries which were downloaded 3900 times in 19 months through April 2011. This large readership indicates such an assignment can generate interest in either undergraduate writing about developing sustainable horticulture and/or the topic area itself, although the exact purpose of the downloads or the location of the users could not be determined. Full article
(This article belongs to the Special Issue Plant Breeding for Sustainable Agriculture)
Open AccessArticle ‘Sufferings Start from the Mothers’ Womb’: Vulnerabilities and Livelihood War of the Small-Scale Fishers of Bangladesh
Sustainability 2011, 3(12), 2500-2527; doi:10.3390/su3122500
Received: 10 August 2011 / Revised: 22 October 2011 / Accepted: 17 November 2011 / Published: 20 December 2011
Cited by 3 | PDF Full-text (897 KB) | HTML Full-text | XML Full-text
Abstract
Due to its deltaic geographical position and precarious socioeconomic and demographic conditions, Bangladesh is recognized worldwide for its exposure to recurring environmental hazards. Based on a 21-month long field study in two fishing villages that are characterized by distinct ecological settings and [...] Read more.
Due to its deltaic geographical position and precarious socioeconomic and demographic conditions, Bangladesh is recognized worldwide for its exposure to recurring environmental hazards. Based on a 21-month long field study in two fishing villages that are characterized by distinct ecological settings and ethnic groups, this article examines the arrays of cross-scale environmental, social and institutional stressors that singly or cumulatively impact fishers’ livelihood well-being and generational poverty. Analysis of the vulnerabilities makes it clear that the degree to which poor fishers suffer from environmental stressors and calamities is determined not only by the frequency of abnormal events, but also by their internal capabilities of self-protection, resilience against those stressors, position in the social network and asset and resource ownership. Coastal and floodplain fishers identified cyclone and long-standing floods as strong drivers of poverty as their bundles of ‘safety net’ capital are usually disrupted or lost. For a majority of the fishers, income/day/family declines to as low as US$ 0.7–0.9. Fishers lack appropriate sets of endowments and entitlements that would allow them immediate buffer against livelihood stressors. Vulnerability here is intricately related to one’s socio-economic status; poor and ‘socially vulnerable’ ethnic fishers are concurrently ‘biologically vulnerable’ too. The corollary of multi-faceted stressors is that, poverty persists as an ever-increasing haunting presence that thousands of floodplain and coastal fishers of Bangladesh are forced to cope with. It is evident that nature-induced stressors exert ‘ratchet effects’ on fishers with low endowments who critically risk nutritional deprivation and social standing. Lucidly, most of the fishers are trapped in a form of livelihood war’. Full article
(This article belongs to the Special Issue Disaster Risk Reduction and Sustainable Development)

Review

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Open AccessReview Seeking to Understand the Reasons for Different Energy Return on Investment (EROI) Estimates for Biofuels
Sustainability 2011, 3(12), 2413-2432; doi:10.3390/su3122413
Received: 5 July 2011 / Revised: 17 November 2011 / Accepted: 24 November 2011 / Published: 13 December 2011
Cited by 19 | PDF Full-text (262 KB) | HTML Full-text | XML Full-text
Abstract
The authors of this paper have been involved in contentious discussion of the EROI of biomass-based ethanol. This contention has undermined, in the minds of some, the utility of EROI for assessing fuels. This paper seeks to understand the reasons for the [...] Read more.
The authors of this paper have been involved in contentious discussion of the EROI of biomass-based ethanol. This contention has undermined, in the minds of some, the utility of EROI for assessing fuels. This paper seeks to understand the reasons for the divergent results. Full article
(This article belongs to the Special Issue New Studies in EROI (Energy Return on Investment))

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