Life Cycle Basis Research Articles

Life cycle environmental impacts of advanced wastewater treatment techniques for removal of pharmaceuticals and personal care products (PPCPs)

Pharmaceutical and personal care products (PPCPs) are of increasing interest because of their ecotoxicological properties and environmental impacts. Wastewater treatment plants (WWTPs) are the main pathway for their release into freshwaters due to the inefficiency of conventional WWTPs in removing many of these contaminants from effluents. Therefore, different advanced effluent treatment techniques have been proposed for their treatment. However, it is not known at present how effective these treatment methods are and whether on a life cycle basis they cause other environmental impacts which may outweigh the benefits of the treatment. In an effort to provide an insight into this question, this paper considers life cycle environmental impacts of the following advanced treatment techniques aimed at reducing freshwater ecotoxicity potential of PPCPs: granular activated carbon (GAC), nanofiltration (NF), solar photo-Fenton (SPF) and ozonation. The results suggest that on average NF has the lowest impacts for 13 out of 18 categories considered. GAC is the best alternative for five impacts, including metals and water depletion, but it has the highest marine eutrophication. SPF and ozonation are the least sustainable for eight impacts, including ecotoxicity and climate change. GAC and NF are also more efficient in treating heavy metals while avoiding generation of harmful by-products during the treatment, thus being more suitable for potable reuse of wastewater. However, releasing the effluent without advanced treatment to agricultural land achieves a much higher reduction of freshwater ecotoxicity than treating it by any of the advanced treatments and releasing to the environment. Therefore, the use of advanced effluent treatment for agricultural purposes is not recommended.

Life cycle efficiency of beef production: IX. Relationship between residual feed intake of heifers and cow efficiency ratios based on harvest, carcass, and wholesale cut weight outputs.

Data were collected from 1953 through 1980 from identical and fraternal twin beef and dairy females born in 1953, 1954, 1959, 1964, and 1969, from crossbred females born as singles in 1974, and their progeny. Numbers of dams that weaned at least one calf and were included in the first analysis were 37, 45, and 56 in the 1964, 1969, and 1974 data sets, respectively. Respective numbers of dams that weaned three calves and were included in a second analysis were 6, 8, 8, 22, 33, and 33 in the 1953, 1954, 1959, 1964, 1969, and 1974 experiments. Individual feed consumption was measured at 28-d intervals from the time females were placed on the experiment at 240 d of age until three calves were weaned or the dams had reached 5 yr of age. Residual feed intake (RFI) and residual BW gain (RG) of heifers that subsequently became dams were determined based on ADG and DMI from 240 d of age to first calving. Various measures of cow efficiency were calculated on either a life cycle or actual lifetime basis using ratios of progeny and dam weight outputs to progeny and dam feed inputs. The correlation between RFI and DMI was large and positive (r = 0.67; P < 0.0001), and RG was highly correlated with ADG (r = 0.75; P < 0.0001). Correlations of RFI with cow efficiency ratios that included harvest weight, carcass weight, or weight of trimmed wholesale cuts as measures of output ranged from -0.05 (P > 0.10) to -0.17 (P < 0.10), indicating that heifers with better (i.e., more negative) RFI values tended to become slightly more efficient cows. Correlations of RG with life cycle and actual lifetime cow efficiency ratios ranged from 0.08 (P > 0.10) to 0.23 (P < 0.05), demonstrating that heifers with better (i.e., more positive) values for RG were somewhat more efficient as cows. The correlations were stronger when cow salvage value was included in the measures of cow efficiency. Correlations of DMI and mid-test metabolic BW (MMW) with life cycle cow efficiency ratios that did not include cow salvage value as output ranged from -0.15 (P < 0.10) to -0.22 (P < 0.01). Correlations of DMI and MMW with actual lifetime cow efficiency ratios varied from -0.20 (P < 0.05) to -0.36 (P < 0.001). Therefore, smaller heifers that consumed less feed had superior cow efficiency ratios. Correlations of RFI with carcass grade, backfat thickness, marbling score, and kidney fat of progeny indicated that heifers with superior RFI would tend to produce leaner offspring.

Environmental Impact Study of Bagasse Valorization Routes

India is the world’s second largest producer of sugarcane and a major manufacturer of molasses-derived ethanol. The sugarcane produced is widely used in the production of sugar and 1G ethanol, leaving behind a huge amount of bagasse as waste. However, sugarcane bagasse also has some end-use value, for example, its utilization for the production of methanol, 2G ethanol, and electricity. Although the technologies for the production of these value-added products are well established, it is important to analyze the social, economic, and environmental impacts associated with their production processes. This work compares the environmental impacts of various sugarcane conversion processes on the life cycle basis. The functional unit used is 1 Ton of sugarcane cultivated on field. Four routes were identified for bagasse utilization: (i) conversion to methanol (route 1), (ii) conversion to ethanol via a two-stage dilute acid process (route 2), (iii) conversion to ethanol via an enzymatic process (route 3), and (iv) electricity generation (route 4). The comparison of bagasse management scenarios to obtain various products is made based on midpoint indicators, such as global warming potential, acidification potential, eutrophication potential, ozone depletion potential, and photochemical ozone creation potential. It was observed that methanol production had the highest environmental indicator values. Ethanol production processes and cogeneration process have nearly similar impacts, although it can be said that cogeneration is more eco-friendly.

Life cycle engineering of lightweight structures

Lightweight structures are increasingly necessary to meet current engineering requirements. Weight reduction in diverse applications such as automobiles or machine tools is achieved either by using less material or by substituting material with a lighter one, which provides more functionality per unit of weight. To be an effective enabler for sustainability, lightweight structures should result in lower environmental impacts per functional unit when compared to conventional structures on a life cycle basis. However, applying new materials and manufacturing processes often leads to an increase in environmental impacts from the raw materials and production stage of the life cycle. Furthermore, end-of-life disassembly and recycling may become more difficult. In addition, the expected efficiency gains from the use of lightweight structures depend on how the overall market and technical systems respond to them. Consequently, the environmental evaluation of lightweight structures in engineering entails various methodological challenges. Organised around a life cycle engineering framework with a focus on eco-effectiveness, this paper provides a comprehensive review of lightweight structure applications and the challenges and opportunities they present in a life cycle engineering context.

Social sustainability assessment of shale gas in the UK

The majority of shale gas studies so far have focused on environmental impacts with few considering societal aspects. This paper presents a first and most comprehensive assessment of the social impacts of shale gas production and utilisation for electricity generation, focusing on the UK context. The assessment has been carried out based on 14 indicators, addressing the following social sustainability issues: employment, health and safety, nuisance, public perceptions, local communities, infrastructure and resources. Shale gas is compared to a range of other electricity options, including other fossil fuels, nuclear and renewables. Where appropriate and possible, the social impacts are evaluated on a life cycle basis. The results suggest that extraction and utilisation of shale gas would lead to a range of benefits, including employment opportunities and financial gains by local communities. However, these are limited and countered by a number of social barriers that need to be overcome, including low public support, noise, traffic, strain on infrastructure (e.g. wastewater treatment facilities), land use conflict and availability of regulatory resources. Furthermore, shale gas does not present a notable opportunity for increasing energy security, unless its production increases significantly above current predictions. These findings can be used by policy makers, operators and other shale gas stakeholders with an interest in the social impacts of shale gas development. The results can also be useful for other countries planning to exploit their shale gas reserves.

Determination of the life cycle climate change impacts of land use and albedo change in algal biofuel production

Life cycle assessments (LCAs) of algal biofuels have typically ignore direct land use change impacts (DLUC), although a few papers have recently shown that the carbon lost from removing the original biomass and disrupting soil organic carbon (SOC) during pond construction can significantly contribute to the climate change impacts. In this study, LCA methods were developed to integrate climate change impacts of DLUC associated with cultivation of microalgae in open ponds and the effects of temporal and geographic variables on algal growth. In addition to direct land use change impacts due to loss of original biomass and the disruption of SOC, this study presents DLUC impacts caused by changing the surface albedo of an area and changing the carbon flux on the land. The methodology is presented with two LCA cases for the production of renewable gasoline from microalgae in climatically similar regions: the Everglades ecoregion and the Tamaulipas-Texas Semi-Arid Plain ecoregion. These were chosen to isolate the differences in DLUC impacts that are created by different land cover types, equalizing the life cycle impacts caused by temperature and solar radiation on algal growth. The DLUC impacts arising from albedo change and carbon flux change contributed significantly to the life cycle climate change impacts and differed between the two climatically similar regions. The baseline life cycle climate change impacts with DLUC impacts in the Everglades are 46.7% higher than those of conventional gasoline, while production in the Tamaulipas-Texas Semi-Arid Plain leads to a 3.0% reduction. The inclusion of albedo change impacts into the DLUC impacts contributed 10.2% of the life cycle climate change impacts in the Everglades and 36.4% in the Tamaulipas. This methodology can help assess the geographically specific sustainability of algal biofuels on a life cycle basis and can guide siting decisions for algal biofuel feedstock production.

A consistent conceptual framework for applying climate metrics in technology life cycle assessment

Comparing the potential climate impacts of different technologies is challenging for several reasons, including the fact that any given technology may be associated with emissions of multiple greenhouse gases when evaluated on a life cycle basis. In general, analysts must decide how to aggregate the climatic effects of different technologies, taking into account differences in the properties of the gases (differences in atmospheric lifetimes and instantaneous radiative efficiencies) as well as different technology characteristics (differences in emission factors and technology lifetimes). Available metrics proposed in the literature have incorporated these features in different ways and have arrived at different conclusions. In this paper, we develop a general framework for classifying metrics based on whether they measure: (a) cumulative or end point impacts, (b) impacts over a fixed time horizon or up to a fixed end year, and (c) impacts from a single emissions pulse or from a stream of pulses over multiple years. We then use the comparison between compressed natural gas and gasoline-fueled vehicles to illustrate how the choice of metric can affect conclusions about technologies. Finally, we consider tradeoffs involved in selecting a metric, show how the choice of metric depends on the framework that is assumed for climate change mitigation, and suggest which subset of metrics are likely to be most analytically self-consistent.

Life cycle assessment of industrial symbiosis in Songmudao chemical industrial park, Dalian, China

Industrial symbiosis is an eco-industrial model to achieve the sustainable development of industrial parks through the exchange of byproducts, especially for the chemical industries which consume a lot of resources and discharge large amounts of pollutants. To highlights the advantages of this arrangement, we identified in and around the synthetic gas chemical industry chain of Songmudao chemical industrial park, Dalian, China. This chain involves seven facilities exchanging water, materials, and energy across an industrial cluster. The life cycle assessment method was used to evaluate each material substitution for primary energy and three environmental impact categories: primary energy, greenhouse gas (GHG) emission, acidification potential, and eutrophication potential. Each material exchange included avoided production and reduced use of virgin materials, avoided treatment or disposal of the byproducts, and any necessary pre-processing or transportation of local byproducts. All exchanges exhibited positive net saving across all environmental impact categories. The results show environmental benefits of the sharing of byproduct resources accrued in a life cycle basis include 13.63 thousand TJ of primary energy, 1218 thousand tCO2e of GHG, 5054.95 tSO2e of acidification, and 215 tPO43+e of eutrophication. The greatest savings occur as a result of sharing steams between the cogeneration power plant and other facilities. In total, the environmental savings realized by this chemical industrial cluster are significant, and industrial symbiosis is an important way for government to meet its environmental goals and promote this eco-industrial model in China. The government should attach importance to industrial symbiosis and make it a feasible method in energy policy.

Natural gas and grid electricity for seawater desalination: An economic and environmental life-cycle comparison

In recent years, natural gas (NG)- and liquefied natural gas (LNG)-based power generation options have been considered as a potential alternative to grid electricity at desalination plants to reliably meet the increasing energy demand and reduce the associated environmental impacts. This study comparatively evaluated on a life cycle basis the economic and environmental cost-benefits of LNG/NG for self-generation of power with those of the grid electricity supply. The analysis conducted showed that for desalination plant sizes of 75–570ML/day, the LNG-based onsite power generation option is 20–30% more economical than the alternative connection to the grid. However, the life cycle cost (LCC) of the LNG-based onsite power generation system is from 43% to up to 86% higher than the NG-based counterpart for desalination plant sizes that increase progressively from 10 to 570ML/day. A sensitivity analysis conducted on two conceptual mid-range capacity seawater desalination plants showed that variations in the electric tariff rate, fuel cost, plant efficiency, and economic parameters affect the LCC of various power supply options. The study also showed that when the grid electricity with a cleaner mix (i.e., low emission factor) is available, this option results in lower GHG emissions than the LNG/NG power source alternatives.

Life cycle energy benefits of carbon nanotubes for electromagnetic interference (EMI) shielding applications

Carbon nanotube (CNT) composites have been developed for use as electromagnetic interference (EMI) shielding in satellites as well as other land-based applications. While CNT composites are costly and energy-intensive to produce relative to existing EMI shielding materials, they may offer both economic and energy benefits when considered on a life cycle basis. CNTs’ unique characteristics and enhanced physical and chemical properties have made them preferable as alternatives to conventional material. In comparing nano-enabled products with existing technologies, it is imperative to account for differences not just in production but also in performance and delivery. In this study, we considered CNT polymer composites as a replacement for aluminum (the current dominant EMI shielding material) on the basis of shielding effectiveness (in dB). Results demonstrate that CNT-enabled composites offer opportunities for more than 50% reduction in the mass of EMI shielding, while maintaining performance levels within ±10 dB of the shielding effectiveness of aluminum. Reduction in the mass of the EMI component of the satellite subsequently affects the total fuel required to launch it into orbit, reducing it by 6% when using CNT composites. Results show nearly 30% reduction of life cycle cumulative energy demand for the CNT polymer composite shielding compared to aluminum, with concomitant environmental benefits.

The life cycle greenhouse gas implications of a UK gas supply transformation on a future low carbon electricity sector

Natural gas used for power generation will be increasingly sourced from more geographically diverse sites, and unconventional sources such as shale and biomethane, as natural gas reserves diminish. A consequential life cycle approach was employed to examine the implications of an evolving gas supply on the greenhouse gas (GHG) performance of a future United Kingdom (UK) electricity system. Three gas supply mixes were developed based on supply trends, from present day to the year 2050. The contribution of upstream gas emissions - such as extraction, processing/refining, - is not fully reported or covered by UK government legislation. However, upstream gas emissions were seen to be very influential on the future electricity systems analysed; with upstream gas emissions per MJ rising between 2.7 and 3.4 times those of the current supply. Increased biomethane in the gas supply led to a substantial reduction in direct fossil emissions, which was found to be critical in offsetting rising upstream emissions. Accordingly, the modelled high shale gas scenario, with the lowest biomethane adoption; resulted in the highest GHG emissions on a life cycle basis. The long-term dynamics of upstream processes are explored in this work to help guide future decarbonisation policies.

Life cycle efficiency of beef production: VIII. Relationship between residual feed intake of heifers and subsequent cow efficiency ratios.

Data were collected from 1953 through 1980 from identical and fraternal twin beef and dairy females born in 1953, 1954, 1959, 1964, and 1969, and from crossbred females born as singles in 1974, and their progeny. Numbers of dams that weaned at least 1 calf and were included in the first analysis were 37, 45, and 56 in the 1964, 1969, and 1974 data sets, respectively. Respective numbers of dams that weaned 3 calves and were included in a second analysis were 6, 8, 8, 22, 33, and 33 in the 1953, 1954, 1959, 1964, 1969, and 1974 experiments. Individual feed consumption was measured at 28-d intervals from the time females were placed on the experiment until 3 calves were weaned or the dams had reached 5 yr of age. Residual feed intake (RFI) and residual gain (RG) of the heifers that subsequently became the dams in this study were determined based on ADG and DMI from 240 d of age to first calving. Various measures of cow efficiency were calculated on either a life cycle or actual lifetime basis using ratios of progeny and dam weight outputs to progeny and dam feed inputs. Residual feed intake was phenotypically independent of ADG and metabolic midweight (MMW), whereas the correlation between RFI and DMI was positive and highly significant ( = 0.67; < 0.0001). Residual gain was highly correlated with ADG ( = 0.75; < 0.0001) and had near 0 correlations with DMI and MMW. Correlations indicated that heifers that ate less and had smaller metabolic midweights from 240 d of age to first calving had superior efficiency ratios as cows. Residual feed intake was not significantly correlated with age at puberty, age at calving, or milk production. Results of this study do not indicate any serious antagonisms of postweaning heifer RFI with subsequent cow and progeny performance traits or with life cycle or actual lifetime cow efficiency. In addition, selection for increased RG would result in earlier ages at calving, but would also tend to result in taller and heavier cows.

The potential environmental consequences of shifts in UK energy policy that impact on electricity generation

Internationally, there has been a move by nations to decarbonise their electricity systems in an effort to tackle rising territorial emissions. No consensus has been fully reached on best approach, which has led to significant divergence in energy policy between countries and a consequential lack of long-term clarity. Additionally, recent UK policy failures, in terms of stimulating greater energy efficiency and encouraging energy innovation, highlight the huge challenge involved in developing and achieving a low carbon future. Steps to decarbonise electricity whilst also providing a secure and affordable supply, can lead to varying life-cycle environmental consequences. A UK research consortium developed three pathways to explore this move to a more electric low carbon future out to 2050. These pathways have been previously evaluated in terms of their life-cycle energy and environmental performance within a wider sustainability framework. Over the course of the project, greater understanding of the generation technologies and the functionality of the overall system under the different regimes were gained. Here, the environmental consequences of the most recent version of the pathways are presented on a life-cycle basis from ‘cradle-to-gate.’ Thus, the environmental impact of technological trends in UK energy policy and their effect on the pathways are explored through a series of sensitivity analyses. The three UK energy futures incorporating ‘disruptive’ technological options were examined based on the phase out of coal use in favour of gas-fired power, ranging penetration levels of carbon capture and storage, and the allocation and fuel type used for combined heat and power. Recommendations are proposed to help frame future energy policy choices in order to limit the environmental consequences of future electricity systems.

Scenarios for Low Carbon and Low Water Electric Power Plant Operations: Implications for Upstream Water Use.

Electric sector water use, in particular for thermoelectric operations, is a critical component of the water-energy nexus. On a life cycle basis per unit of electricity generated, operational (e.g., cooling system) water use is substantially higher than water demands for the fuel cycle (e.g., natural gas and coal) and power plant manufacturing (e.g., equipment and construction). However, could shifting toward low carbon and low water electric power operations create trade-offs across the electricity life cycle? We compare business-as-usual with scenarios of carbon reductions and water constraints using the MARKet ALlocation (MARKAL) energy system model. Our scenarios show that, for water withdrawals, the trade-offs are minimal: operational water use accounts for over 95% of life cycle withdrawals. For water consumption, however, this analysis identifies potential trade-offs under some scenarios. Nationally, water use for the fuel cycle and power plant manufacturing can reach up to 26% of the total life cycle consumption. In the western United States, nonoperational consumption can even exceed operational demands. In particular, water use for biomass feedstock irrigation and manufacturing/construction of solar power facilities could increase with high deployment. As the United States moves toward lower carbon electric power operations, consideration of shifting water demands can help avoid unintended consequences.

Time‐dependent life cycle assessment of microalgal biorefinery co‐products

AbstractMicroalgae can serve as a highly productive biological feedstock for fuels and chemicals. The lipid fraction has been the primary target of research, but numerous assessments have found that valorization of co‐products is essential to achieve economic and environmental goals. The relative proportion of co‐products depends on the biomolecular composition of algae at the time of harvesting. In the present study, the productivity of lipid, starch, and protein fractions were shown through growth experiments to vary widely with species, feeding regime, and harvesting period. Four algae species were cultivated under nitrogen‐replete and ‐deplete conditions and analyzed at 3‐day intervals. Dynamic growth results were then used for life cycle assessment using the US Department of Energy's GREET model to determine optimal growth scenarios that minimize life cycle greenhouse gas (GHG) emissions, eutrophication, and cumulative energy demand (CED), while aiming for an energy return on investment (EROI) greater than unity. Per kg of biodiesel produced, C. sorokiniana in N‐replete conditions harvested at 12 days was most favorable for GHG emissions and CED, despite having a lipid content of &lt;20%. N. oculata in N‐deplete conditions with a 12‐day harvesting period had the lowest life cycle eutrophication impacts, driven by efficient nutrient cycling and valorization of microalgal protein and anaerobic digester residue co‐products. Results indicate that growth cycle times that maximize a single fraction do not necessarily result in the most favorable environmental performance on a life cycle basis, underscoring the importance of designing biorefinery systems that ‐simultaneously optimize for lipid and non‐lipid fractions. © 2016 Society of Chemical Industry and John Wiley &amp; Sons, Ltd

Assessing the environmental sustainability of energy recovery from municipal solid waste in the UK

Even though landfilling of waste is the least favourable option in the waste management hierarchy, the majority of municipal solid waste (MSW) in many countries is still landfilled. This represents waste of valuable resources and could lead to higher environmental impacts compared to energy recovered by incineration, even if the landfill gas is recovered. Using life cycle assessment (LCA) as a tool, this paper aims to find out which of the following two options for MSW disposal is more environmentally sustainable: incineration or recovery of biogas from landfills, each producing either electricity or co-generating heat and electricity. The systems are compared on a life cycle basis for two functional units: ‘disposal of 1 tonne of MSW’ and ‘generation of 1kWh of electricity’. The results indicate that, if both systems are credited for their respective recovered energy and recyclable materials, energy from incineration has much lower impacts than from landfill biogas across all impact categories, except for human toxicity. The impacts of incineration co-generating heat and electricity are negative for nine out of 11 categories as the avoided impacts for the recovered energy and materials are higher than those caused by incineration. By improving the recovery rate of biogas, some impacts of landfilling, such as global warming, depletion of fossil resources, acidification and photochemical smog, would be significantly reduced. However, most impacts of the landfill gas would still be higher than the impacts of incineration, except for global warming and human toxicity. The analysis on the basis of net electricity produced shows that the LCA impacts of electricity from incineration are several times lower in comparison to the impacts of electricity from landfill biogas. Electricity from incineration has significantly lower global warming and several other impacts than electricity from coal and oil but has higher impacts than electricity from natural gas or UK grid. At the UK level, diverting all MSW currently landfilled to incineration with energy recovery would not only avoid the environmental impacts associated with landfilling but, under the current assumptions, would also meet 2.3% of UK’s electricity demand and save 2–2.6million tonnes of greenhouse gas emissions per year.

Assessing the Environmental Sustainability of Electricity Generation in Turkey on a Life Cycle Basis

Turkey’s electricity mix is dominated by fossil fuels, but the country has ambitious future targets for renewable and nuclear energy. At present, environmental impacts of electricity generation in Turkey are unknown so this paper represents a first attempt to fill this knowledge gap. Taking a life cycle approach, the study considers eleven impacts from electricity generation over the period 1990–2014. All 516 power plants currently operational in Turkey are assessed: lignite, hard coal, natural gas, hydro, onshore wind and geothermal. The results show that the annual impacts from electricity have been going up steadily over the period, increasing by 2–9 times, with the global warming potential being higher by a factor of five. This is due to a four-fold increase in electricity demand and a growing share of fossil fuels. The impact trends per unit of electricity generated differ from those for the annual impacts, with only four impacts being higher today than in 1990, including the global warming potential. Most other impacts are lower from 35% to two times. These findings demonstrate the need for diversifying the electricity mix by increasing the share of domestically-abundant renewable resources, such as geothermal, wind, and solar energy.

Energy and Cost Analyses of Solar Photovoltaic (PV) Microgeneration Systems for Different Climate Zones of Turkey

The environmental and energy problems that have arisen in Turkey because of the dramatically increase in energy consumption require the implementation of energy efficiency and microgeneration measures in the building sector which is the main sector of primary energy consumption. Since Turkey is highly dependent on exported energy resources, the basic energy policy approach is based on providing the supply security. In this regard, supporting for in situ energy production, encouraging the use of renewable energy sources and the systems such as microgeneration systems in order to meet the energy requirements of buildings would be considered as a key measure for resolving the energy related challenges of Turkey and dealing with the sustainability issues. Turkey’s geographical location has several advantages for extensive use of most of the renewable energy sources such as especially solar energy. However, this huge solar energy potential is not being used sufficiently in residential building sector which is responsible for the great energy consumption of Turkey. Therefore, this paper aims to introduce a study which investigates, on a life cycle basis, the environmental and the economic sustainability of solar Photovoltaic (PV) microgenerators to promote the implementation of this system as an option for the renovation of existing residential buildings in Turkey. In this study, main parameters which were related to the distribution of modules to be installed in flat roofs and facades and the evaluation of the PV systems were taken into account. The effect of these parameters on energy generation of PV systems was analyzed in a case study considering different climate zones of Turkey; and the decrease in the existing energy consumption of the reference building was calculated.

Environmental and financial implications of ethanol as a bioethylene feedstock versus as a transportation fuel

Bulk chemicals production from biomass may compete with biofuels for low-cost and sustainable biomass sources. Understanding how alternative uses of biomass compare in terms of financial and environmental parameters is therefore necessary to help ensure that efficient uses of resources are encouraged by policy and undertaken by industry. In this paper, we compare the environmental and financial performance of using ethanol as a feedstock for bioethylene production or as a transport fuel in the US life cycle-based models are developed to isolate the relative impacts of these two ethanol uses and generate results that are applicable irrespective of ethanol production pathway. Ethanol use as a feedstock for bioethylene production or as a transport fuel leads to comparable greenhouse gas (GHG) emissions and fossil energy consumption reductions relative to their counterparts produced from fossil sources. By displacing gasoline use in vehicles, use of ethanol as a transport fuel is six times more effective in reducing petroleum energy use on a life cycle basis. In contrast, bioethylene predominately avoids consumption of natural gas. Considering 2013 US ethanol and ethylene market prices, our analysis shows that bioethylene is financially viable only if significant price premiums are realized over conventional ethylene, from 35% to 65% depending on the scale of bioethylene production considered (80 000 t yr−1 to 240 000 t yr−1). Ethanol use as a transportation fuel is therefore the preferred pathway considering financial, GHG emissions, and petroleum energy use metrics, although bioethylene production could have strategic value if demand-side limitations of ethanol transport fuel markets are reached.

Assessment of residential building performances for the different climate zones of Turkey in terms of life cycle energy and cost efficiency

In residential buildings, the usage of non-renewable resources, which are scarce and exhaustible, the negative impacts of resource usage on the environment and the high energy costs require the evaluation of residential energy performance on a life cycle basis. Therefore, in the framework of this study, it is intended that the measures effective in the improvement of residential energy performance aimed at providing optimum use for the country sources and the decision makers are developed for the different climate zones. Regarding these measures, the energy, economic and environmental performances of residential buildings are evaluated on the basis of life cycle. The effects of the approach developed in accordance with this purpose and the considered improvement measures on life cycle energy consumption, CO2 emissions and the costs are evaluated within the framework of “life cycle assessment” (LCA) and “life cycle cost” (LCC) methods. So, in the design of new residential buildings or the improvement of the existing residentials, the results which generate data for the regulations concerning the optimisation of energy, and economic and environmental performances regarding the life cycle of residential building, can be enabled.