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1.
This paper presents a life cycle assessment (LCA) of industrial scale microalgae biomass production in compact photobioreactor (PBR) systems (2 × 5 × 8 m) for supplying biofuel/electricity generation processes and synthesis of new materials. Other objectives are as follows: (i) to compare the impact of various raw materials, substances, and services; and (ii) to evaluate environment‐relevant aspects of the proposed system as compared to microalgae raceway ponds. The life cycle inventory assessment shows that (i) only atmospheric CO2 is used for PBR microalgae cultivation, whereas in raceway ponds, injection of CO2 from fossil origin is largely required to allow for microalgae growth; and (ii) the PBR daily production rate of dry biomass is currently at 1.5 kg m?3 day?1 for each PBR, which is 12.82 times larger than the reported average 0.117 kg m?3 day?1 raceway ponds production. It is found that in general the association of the effects of the production of steel, PVC, and the packaging contribute to more than 85% of the total impact in each analyzed category. Therefore, to achieve PBR biomass production impact reduction and sustainability, PVC and steel utilization need to be minimized, as well as packaging materials. Based on the PBR LCA results, that is, due to no CO2 injection from fossil origin and low area occupation, it is expected that high density production of truly renewable microalgae biomass could be obtained from PBR systems.  相似文献   

2.

Purpose

Oceans offer a vast amount of renewable energy. Tidal and wave energy devices are currently the most advanced conduits of ocean energy. To date, only a few life cycle assessments for ocean energy have been carried out for ocean energy. This study analyses ocean energy devices, including all technologies currently being proposed, in order to gain a better understanding of their environmental impacts and explore how they can contribute to a more sustainable energy supply.

Methods

The study followed the methodology of life cycle assessment including all life cycle steps from cradle to grave. The various types of device were assessed, on the basis of a functional unit of 1 kWh of electricity delivered to the grid. The impact categories investigated were based on the ILCD recommendations. The life cycle models were set up using detailed technical information on the components and structure of around 180 ocean energy devices from an in-house database.

Results and discussion

The design of ocean energy devices still varies considerably, and their weight ranges from 190 to 1270 t, depending on device type. Environmental impacts are closely linked to material inputs and are caused mainly by mooring and foundations and structural components, while impacts from assembly, installation and use are insignificant for all device types. Total greenhouse gas emissions of ocean energy devices range from about 15 to 105 g CO2-eq. kWh?1. Average global warming potential for all device types is 53?±?29 g CO2-eq. kWh?1. The results of this study are comparable with those of other studies and confirm that the environmental impacts of ocean energy devices are comparable with those of other renewable technologies and can contribute to a more sustainable energy supply.

Conclusions

Ocean energy devices are still at an early stage of development compared with other renewable energy technologies. Their environmental impacts can be further reduced by technology improvements already being pursued by developers (e.g. increased efficiency and reliability). Future life cycle assessment studies should assess whole ocean energy arrays or ocean energy farms.
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3.
4.
Goal, Scope and Background  The automotive industry has a long history in improving the environmental performance of vehicles - fuel economy and emission improvements, introduction of recycled and renewable materials, etc. The European Union also aims at improving the environmental performance of products by reducing, in particular, waste resulting from End-of-Life Vehicles (ELVs) for example. The European Commission estimates that ELVs contribute to approximately 1 % of the total waste in Europe [9]. Other European Union strategies are considering more life cycle aspects, as well as other impacts including resource or climate change. This article is summarizing the results of a European Commission funded project (LIRECAR) that aims at identifying the environmental impacts and relevance for combinations of recycling / recovery and lightweight vehicle design options over the whole life cycle of a vehicle - i.e. manufacturing, use and recycling/recovery. Three, independent and scientific LCA experts reviewed the study according to ISO 14040. From the beginning, representatives of all Life Cycle Stakeholders have been involved (European materials & supplier associations, an environmental Non-Governmental Organization, recycler’s association). Model and System Definition  The study compared 3 sets of theoretical vehicle weight scenarios: 1000 kg reference (material range of today’s end-of-life, mid-sized vehicles produced in the early 1990’s) and 2 lightweight scenarios for 100 kg and 250 kg less weight based on reference functions (in terms of comfort, safety, etc.) and a vehicle concept. The scenarios are represented by their material range of a broad range of lightweight strategies of most European car manufacturers. In parallel, three End-of-Life (EOL) scenarios are considered: EOL today and two theoretical extreme scenarios (100% recycling, respectively, 100% recovery of shredder residue fractions that are disposed of today). The technical and economical feasibility of the studied scenarios is not taken into consideration (e.g. 100% recycling is not possible). Results and Discussion  Significant differences between the various, studied weight scenarios were determined in several scenarios for the environmental categories of global warming, ozone depletion, photochemical oxidant creation (summer smog), abiotic resource depletion, and hazardous waste. However, these improvement potentials can be only realized under well defined conditions (e.g. material compositions, specific fuel reduction values and EOL credits) based on case-by-case assessments for improvements over the course of the life cycle. Looking at the studied scenarios, the relative contribution of the EOL phase represents 5% or less of the total life cycle impact for most selected impact categories and scenarios. The EOL technology variations studied do not impact significantly the considered environmental impacts. Exceptions include total waste, as long as stockpile goods (overburden, tailings and ore/coal processing residues) and EOL credits are considered. Conclusions and Recommendations  LIRECAR focuses only on lightweight/recycling, questions whereas other measures (changes in safety or comfort standards, propulsion improvements for CO2, user behavior) are beyond the scope of the study. The conclusions are also not necessarily transferable to other vehicle concepts. However, for the question of end-of-life options, it can be concluded that LIRECAR cannot support any general recommendation and/or mandatory actions to improve recycling if lightweight is affected. Also, looking at each vehicle, no justification could be found for the general assumption that lightweight and recycling greatly influence the affected environmental dimension (Global Warming Potential or resource depletion and waste, respectively). LIRECAR showed that this general assumption is not true under all analyzed circumstances and not as significant as suggested. Further discussions and product development targets shall not focus on generic targets that define the approach/technology concerned with how to achieve environmental improvement (weight reduction [kg], recycling quota [%]), but on overall life cycle improvement). To enable this case-by-case assessment, exchanges of necessary information with suppliers are especially relevant.  相似文献   

5.

Purpose

Global beer consumption is growing steadily and has recently reached 187.37 billion litres per year. The UK ranked 8th in the world, with 4.5 billion litres of beer produced annually. This paper considers life cycle environmental impacts and costs of beer production and consumption in the UK which are currently unknown. The analysis is carried out for two functional units: (i) production and consumption of 1 l of beer at home and (ii) annual production and consumption of beer in the UK. The system boundary is from cradle to grave.

Methods

Life cycle impacts have been estimated following the guidelines in ISO 14040/44; the methodology for life cycle costing is congruent with the LCA approach. Primary data have been obtained from a beer manufacturer; secondary data are sourced from the CCaLC, Ecoinvent and GaBi databases. GaBi 4.3 has been used for LCA modelling and the environmental impacts have been estimated according to the CML 2001 method.

Results and discussion

Depending on the type of packaging (glass bottles, aluminium and steel cans), 1 l of beer requires for example 10.3–17.5 MJ of primary energy and 41.2–41.8 l of water, emits 510–842 g of CO2 eq. and has the life cycle costs of 12.72–14.37 pence. Extrapolating the results to the annual consumption of beer in the UK translates to a primary energy demand of over 49,600 TJ (0.56 % of UK primary energy consumption), water consumption of 1.85 bn hl (5.3 % of UK demand), emissions of 2.16 mt CO2 eq. (0.85 % of UK emissions) and the life cycle costs of £553 million (3.2 % of UK beer market value). Production of raw materials is the main hotspot, contributing from 47 to 63 % to the impacts and 67 % to the life cycle costs. The packaging adds 19 to 46 % to the impacts and 13 % to the costs.

Conclusions

Beer in steel cans has the lowest impacts for five out of 12 impact categories considered: primary energy demand, depletion of abiotic resources, acidification, marine and freshwater toxicity. Bottled beer is the worst option for nine impact categories, including global warming and primary energy demand, but it has the lowest human toxicity potential. Beer in aluminium cans is the best option for ozone layer depletion and photochemical smog but has the highest human and marine toxicity potentials.
  相似文献   

6.

Purpose

The industrial ecosystem identified in and around the Campbell Industrial Park in Honolulu County, Hawai’i involves 11 facilities exchanging water, materials, and energy across an industrial cluster. This paper highlights the advantages of this arrangement using life cycle assessment to determine the energy and environmental costs and benefits of the existing pattern of exchanges.

Methods

A consequential approach was used to evaluate each material substitution for four environmental impact categories: primary energy use, greenhouse gas (GHG) emissions, acidification, and eutrophication. Each material exchange included avoided production and reduced use of virgin materials, any necessary pre-processing or transportation of local by-products, and avoided treatment or disposal of these by-products.

Results and discussion

All exchanges exhibited positive net savings across all environmental impact categories, with the exceptions of waste oil and tire-derived fuel burned as substitutes for coal. The greatest savings occur as a result of sharing steam between a combined cycle fuel oil-fired cogeneration plant and a nearby refinery. In total, the environmental savings realized by this industrial cluster are significant, equivalent to 25 % of the state’s policy goal for reducing the industrial component of GHG emissions over the next decade. The role of policy in supporting material and energy exchanges is also discussed as the central cluster of two power plants and two refineries share steam and water in part under regulatory requirements.

Conclusions

The results show environmental benefits of the sharing of by-product resources accrued on a life cycle basis, while for the local context, the reduction of imported fuels and materials helps to reduce the external dependency of Oahu’s remote island economy. The environmental benefits of materials exchanges are often ignored in energy policy, though, as in this case, they can represent considerable savings.  相似文献   

7.

Goal, Scope and Background  

The goal of this paper is to present the modeling of life cycle inventory (LCI) for electric energy production and delivery in Brazil for the reference year 2000 by application of ISO 14040. Site specific data along with sector production data have been combined to construct an energy production model, which has been applied to emissions estimation. Background-data of all the inputs and outputs from the system have been inventoried as follows: gross electric energy generation, installed nameplate capacity, flooded area, losses, emissions to air / water, process waste, used fuel, efficiency and land use.  相似文献   

8.

Purpose  

The demand of PET bottles has increased rapidly in the past decades. The purpose of this study is to understand the environmental impact of PET recycling system, in which used bottles are recycled into both fibre and bottles, and to compare the recycling system with single-use PET.  相似文献   

9.
Background, Aim and Scope The objective of this life cycle assessment (LCA) study is to develop LCA models for energy systems in order to assess the potential environmental impacts that might result from meeting energy demands in buildings. The scope of the study includes LCA models of the average electricity generation mix in the USA, a natural gas combined cycle (NGCC) power plant, a solid oxide fuel cell (SOFC) cogeneration system; a microturbine (MT) cogeneration system; an internal combustion engine (ICE) cogeneration system; and a gas boiler. Methods LCA is used to model energy systems and obtain the life cycle environmental indicators that might result when these systems are used to generate a unit energy output. The intended use of the LCA analysis is to investigate the operational characteristics of these systems while considering their potential environmental impacts to improve building design using a mixed integer linear programming (MILP) optimization model. Results The environmental impact categories chosen to assess the performance of the energy systems are global warming potential (GWP), acidification potential (AP), tropospheric ozone precursor potential (TOPP), and primary energy consumption (PE). These factors are obtained for the average electricity generation mix, the NGCC, the gas boiler, as well as for the cogeneration systems at different part load operation. The contribution of the major emissions to the emission factors is discussed. Discussion The analysis of the life cycle impact categories indicates that the electrical to thermal energy production ratio has a direct influence on the value of the life cycle PE consumption factors. Energy systems with high electrical to thermal ratios (such as the SOFC cogeneration systems and the NGCC power plant) have low PE consumption factors, whereas those with low electrical to thermal ratios (such as the MT cogeneration system) have high PE consumption factors. In the case of GWP, the values of the life cycle GWP obtained from the energy systems do not only depend on the efficiencies of the systems but also on the origins of emissions contributing to GWP. When evaluating the life cycle AP and TOPP, the types of fuel as well as the combustion characteristics of the energy systems are the main factors that influence the values of AP and TOPP. Conclusions An LCA study is performed to eraluate the life cycle emission factors of energy systems that can be used to meet the energy demand of buildings. Cogeneration systems produce utilizable thermal energy when used to meet a certain electrical demand which can make them an attractive alternative to conventional systems. The life cycle GWP, AP, TOPP and PE consumption factors are obtained for utility systems as well as cogeneration systems at different part load operation levels for the production of one kWh of energy output. Recommendations and Perspectives Although the emission factors vary for the different energy systems, they are not the only factors that influence the selection of the optimal system for building operations. The total efficiencies of the system play a significant part in the selection of the desirable technology. Other factors, such as the demand characteristics of a particular building, influence the selection of energy systems. The emission factors obtained from this LCA study are used as coefficients of decision variables in the formulation of an MILP to optimize the selection of energy systems based on environmental criteria by taking into consideration the system efficiencies, emission characteristics, part load operation, and building energy demands. Therefore, the emission factors should not be regarded as the only criteria for choosing the technology that could result in lower environmental impacts, but rather one of several factors that determine the selection of the optimum energy system. ESS-Submission Editor: Arpad Horvath (horvath@ce.berkeley.edu)  相似文献   

10.
Aim, Scope and Background The paper proposes the assessment of the environmental interventions resulting from the electrical energy production in Romania, a Central East European country, using the LCA technique limited to a Life Cycle Inventory study (an LCA without the Life Cycle Impact Assessment phase). Main Features The following life cycles of the energy carriers employed in the production of the electrical energy are analysed according to their provenance: lignite (domestic) 31.2%, brown coal (domestic) 3.4%, brown coal (import) 0.4%, heavy oil (domestic, land) 4.2%, heavy oil (domestic, continental platform of the Black Sea) 0.4%, heavy oil (import) 3.6%, natural gas (domestic) 12.4%, natural gas (import) 6.1%, hydropower 27.8%, and nuclear energy 10.5% from the total of the electrical energy produced in Romania. The unit processes of the life cycles of these energy carriers are aggregated in two main stages: Pre-combustion (extraction, processing, transport and achievement of infrastructure) and Combustion (the production of electricity). The functional unit of the study is represented by 1 kwh. The spatial limits of the analysed system are extended as far as CIS countries for coal, Western Siberia (Russian Federation) for natural gas and the OPEC countries for oil. The temporal limits are included in the year 2000. Results and Discussion The LCI study enabled us to quantify the interventions on the environment, which result from the electricity production in Romania, the independent use of different energy carriers and the different life cycle stages of the system. The use of the LCA technique in a prospective way shows the reduction of these interventions that could be achieved through the adoption of specific scenarios for the development of electrical energy production in the country. Conclusions The main findings of this Life Cycle Inventory study, the first for Romania, are: the emissions of pollutant substances are prevailing in the combustion stage; for different energy carriers, the magnitude of environmental interventions decrease in the following order: coal, oil, natural gas, hydropower and nuclear energy. By comparison with other countries, the environment is more affected by the production of electricity in the case of Romania and only the promotion of alternative, renewable resources such as hydropower could substantially improve these interventions. Recommendations and Perspectives Some important interactions with the environment, like land use or the risks of the nuclear energy, are not taken into consideration in the study because of the lack of particular data for Romania. We would like to continue the investigation in order to surpass the limits of the study, on the one hand by collecting data concerning the risk of nuclear power or land use at the national level for different energy carriers or, on the other hand, by taking into account some other renewable resources like wind or solar energy.  相似文献   

11.
Despite claims that microalgal biofuels are environmentally friendlier alternatives to conventional fuels, debate surrounding its ecological benefits or drawbacks still exists. LCA is used to analyze various biofuel production technologies from ‘cradle to gate’. Energy and CO2 balances are carried out for a hypothetical integrated PBR-raceway microalgae-to-biodiesel production in Singapore. Based on a functional unit of 1 MJ biofuel, the total energy demands are 4.44 MJ with 13% from biomass production, 85% from lipid extraction, and 2% from biodiesel production. Sensitivity analysis was carried out for adjustments in energy requirements, percentage lipid contents, and lower/higher heating product value. An ‘Optimistic Case’ was projected with estimates of: 45% lipid content; reduced energy needs for lipid extraction (1.3 MJ per MJ biodiesel); and heating value of biodiesel (42 MJ/kg). The life cycle energy requirements dropped significantly by about 60%. The results are compared with other published case studies from other countries.  相似文献   

12.

Purpose  

Building is one of the main factors of energy use and greenhouse gas emissions. Reducing energy consumption and carbon dioxide (CO2) emission from building is urgent for environmental protection and sustainable development. The objective of this study is to develop a life cycle assessment (LCA) model for an office building in China to assess its energy consumption and CO2 emission, determine the whole life cycle phases, and the significant environmental aspects that contribute most to the impact.  相似文献   

13.
Life cycle assessment (LCA) was combined with primary data from nine forest harvesting operations in New York, Maine, Massachusetts, and Vermont, from 2013 to 2019 where forest biomass (FB) for bioenergy was one of several products. The objective was to conduct a data‐driven study of greenhouse gas emissions associated with FB feedstock harvesting operations in the Northeast United States. Deterministic and stochastic LCA models were built to simulate the current FB bioenergy feedstock supply chain in the Northeast US with a cradle‐to‐gate scope (forest harvest through roadside loading) and a functional unit of 1.0 Mg of green FB feedstock at a 50% moisture content. Baseline LCA, sensitivity analysis, and uncertainty analyses were conducted for three different FB feedstock types—dirty chips, clean chips, and grindings—enabling an empirically driven investigation of differences between feedstock types, individual harvesting process contributions, and literature comparisons. The baseline LCA average impacts were lower for grindings (4.57 kg CO2eq/Mg) and dirty chips (7.16 kg CO2eq/Mg) than for clean chips (23.99 kg CO2eq/Mg) under economic allocation, but impacts were of similar magnitude under mass allocation, ranging from 24.42 to 27.89 kg CO2eq/Mg. Uncertainty analysis showed a wider range of probable results under mass allocation compared to economic allocation. Sensitivity analysis revealed the impact of variations in the production masses and total economic values of primary products of forest harvests on the LCA results due to allocation of supply chain emissions. The high variability in fuel use between logging contractors also had a distinct influence on LCA results. The results of this study can aid decision‐makers in energy policy and guide emissions reductions efforts while informing future LCAs that expand the system boundary to regional FB energy pathways, including electricity generation, transportation fuels, pellets for heat, and combined heat and power.  相似文献   

14.
15.
玉米秸秆基纤维素乙醇生命周期能耗与温室气体排放分析   总被引:2,自引:0,他引:2  
生命周期评价是目前分析产品或工艺的环境负荷唯一标准化工具,利用其生命周期分析方法可以有效地研究纤维素乙醇生命周期能耗与温室气体排放问题。为了定量解释以玉米秸秆为原料的纤维素乙醇的节能和温室气体减排潜力,利用生命周期分析方法对以稀酸预处理、酶水解法生产的玉米秸秆基乙醇进行了生命周期能耗与温室气体排放分析,以汽车行驶1 km为功能单位。结果表明:与汽油相比,纤维素乙醇E100 (100%乙醇) 和E10 (乙醇和汽油体积比=1∶9) 生命周期化石能耗分别减少79.63%和6.25%,温室气体排放分别减少53.98%和6.69%;生物质阶段化石能耗占到总化石能耗68.3%,其中氮肥和柴油的生命周期能耗贡献最大,分别占到生物质阶段的45.78%和33.26%;工厂电力生产过程的生命周期温室气体排放最多,占净温室气体排放量的42.06%,提升技术减少排放是降低净排放的有效措施。  相似文献   

16.

Purpose

Two different bioenergy systems using willow chips as raw material has been assessed in detail applying life cycle assessment (LCA) methodology to compare its environmental profile with conventional alternatives based on fossil fuels and demonstrate the potential of this biomass as a lignocellulosic energy source.

Methods

Short rotation forest willow plantations dedicated to biomass chips production for energy purposes and located in Southern Sweden were considered as the agricultural case study. The bioenergy systems under assessment were based on the production and use of willow-based ethanol in a flexi fuel vehicle blended with gasoline (85 % ethanol by volume) and the direct combustion of willow chips in an industrial furnace in order to produce heat for end users. The standard framework for LCA from the International Standards Organisation was followed in this study. The environmental profiles as well as the hot spots all through the life cycles were identified.

Results and discussion

According to the results, Swedish willow biomass production is energetically efficient, and the destination of this biomass for energy purposes (independently the sort of energy) presents environmental benefits, specifically in terms of avoided greenhouse gases emissions and fossil fuels depletion. Several processes from the agricultural activities were identified as hot spots, and special considerations should be paid on them due to their contribution to the environmental impact categories under analysis. This was the case for the production and use of the nitrogen-based fertilizer, as well as the diesel used in agricultural machineries.

Conclusions

Special attention should be paid on diffuse emissions from the ethanol production plant as well as on the control system of the combustion emissions from the boiler.  相似文献   

17.
Total energy costs in ecosystems   总被引:1,自引:0,他引:1  
A micro and macro ecological system hypotheses and their associated theory of total (direct and indirect) energy cost have been proposed to explain the meaning of system growth and the steady state condition. Models have been proposed which can be used to test the hypotheses. In brief, the hypotheses are that while the components of an ecosystem strive to maximize their total direct and indirect energy storage within the constraints of their production characteristics, the overall system strives to minimize the metabolized energy per unit of stored biomass energy. The steady state result is a system with the largest possible stored biomass under the general constraints of water, air, soil and sunlight availability.Feeding strategies are discussed with the conclusion that a net total energy-maximizing feeding strategy may be able to replace the present concepts.  相似文献   

18.

Background, aim and scope  

Biodiesel derived from Waste Cooking Oil (WCO) is considered highly environmentally sustainable since WCO is a waste product from domestic and commercial cooking processes and then recycled to a transportation fuel in Singapore. In addition, it avoids the conversion of land use for crop production. This is a strong advantage for Singapore which has relatively smaller land space than other countries. The import of virgin oil as feedstock into Singapore is also avoided. Therefore, the more appropriate feedstock to produce biodiesel in Singapore context is WCO. According to the National Environment Agency, diesel vehicles in Singapore contribute 50% of the total particulate matter smaller than 2.5 μm (PM0.25) emissions to air ambient. Hence, the aim of this life cycle assessment study was to compare the environmental performances of biodiesel derived from WCO and low sulphur diesel in terms of global warming potential, life cycle energy efficiency (LCEE) and fossil energy ratio (FER) using the life cycle inventory. The results of this study would serve as a reference for energy policy makers and environmental agencies.  相似文献   

19.
Buildings represent a critical piece of a low‐carbon future, and their long lifetime necessitates urgent adoption of state‐of‐the‐art performance standards to avoid significant lock‐in risk regarding long‐lasting technology solution choices. Buildings, mobility, and energy systems are closely linked, and assessing their nexus by aiming for Zero Emission Neighborhoods (ZENs) provides a unique chance to contribute to climate change mitigation. We conducted a life‐cycle assessment of a Norwegian ZEN and designed four scenarios to test the influence of the house size, household size, and energy used and produced in the buildings as well as mobility patterns. We ran our scenarios with different levels of decarbonization of the electricity mix over a period of 60 years. Our results show the importance of the operational phases of both the buildings and mobility in the neighborhood's construction, and its decline over time induced by the decarbonization of the electricity mix. At the neighborhood end‐of‐life, embodied emissions then become responsible for the majority of the emissions when the electricity mix is decarbonized. The choice of functional unit is decisive, and we thus argue for the use of a primary functional unit “per neighborhood,” and a second “per person.” The use of a “per m2” functional unit is misleading as it does not give credits to the precautionary use of floor area. To best mitigate climate change, climate‐positive behaviors should be combined with energy efficiency standards that incorporate embodied energy, and absolute threshold should be combined with behavioral changes.  相似文献   

20.
The newly emerging LCA standards provide an opportunity to review and improve upon the current LCA methodology. As more industrial practitioners enter the arena, the opportunity arises to not only demand environmental improvement from industrial service and product providers but also to fill LCA data gaps. A framework is suggested for improvement in the current LCA framework that focuses on the business relationships of the industrial practitioner. The framework seeks to promote environmental improvement from industrial sectors through the identification of state-of-the-art technologies used throughout a life cycle. Basing LCAs on the best performers in an industry will create a market for a high level of environmental performance, disperse the responsibility of inventory data gathering, and improve upon the advancements already anticipated through the widespread application of LCA.  相似文献   

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