A life cycle approach to Green Public Procurement of building materials and elements: A case study on windows

Green Public Procurement (GPP) is a significant policy tool for reducing the environmental impacts of services and products throughout their whole life cycle. Scientific and easily verifiable environmental criteria, based on a life cycle approach, should be developed and used within procurement procedures. In this paper, Life Cycle Assessment (LCA) is applied to wood windows showing how it can support the criteria definition. After a foreword on GPP development in Italy, the evaluation features of the environmental performances of building materials and components are outlined. The LCA case study is then presented, describing the use of the analysis results to define the environmental criteria. LCA allowed to identify the main impacts and the critical processes of the window life cycle, giving a scientific framework to discuss GPP criteria with manufacturers associations and stakeholders. Nevertheless, it couldn’t help neither in identifying detailed criteria for GPP nor to define numerical thresholds to be used as reference in procurement procedures. The appropriate strategies should be selected taking into account the technical status of the market, the standard development and the voluntary industry commitments, involving manufacturers associations. Finally, some elements to develop a structured approach for GPP of construction materials are presented.     

Life cycle and life cycle cost implications of integrated phase change materials in office buildings

The investigation of the use of phase change materials (PCM) in the building sector has become a significant issue and a field exhibiting significant potential in terms of research and development. The present study evaluates the integration of PCMs in office buildings on the basis of their economic and environmental performance by means of life cycle analysis (LCA) in conjunction with life cycle cost analysis (LCCA) respectively. This study is based on a previous building envelope multiobjective optimization study which considers cooling load requirements and thermal comfort conditions as optimization objectives. Specifically, this work moves 1 step further to evaluate the optimal results obtained from the above‐mentioned optimization study based on economic and environmental aspects. This paper attempts to evaluate and quantify the environmental and economic potential of PCM use in office buildings in a generic way. In detail, the present study starts by examining whether reducing the extent of the environmental impact achieved during the operational phase from energy savings offsets the respective increase arising from the PCM production. The LCA results reveal that the overall life cycle impact of the 2 office units examined is reduced, despite the respective impact of the construction stage increasing significantly, given the high proportion of impact accruing from the energy use stage in the overall impact. Finally, a life cycle cost evaluation assesses the viability of such applications, with the conclusion that the energy saving achieved during the use stage in both office units is insufficient to compensate for the LCC increase induced by the high cost of construction.     

A multi-criteria evaluation framework for tradable white certificate schemes

Recent years have witnessed regained political momentum on energy efficiency and interest in establishing markets is growing. As a result, Tradable White Certificate (TWC) schemes of differing design have been implemented in Great Britain, Italy and France. Much attention is being paid to justifying and evaluating such schemes. In this paper, we develop and apply a multi-criteria framework for evaluating TWC schemes—an approach that attempts to cover their individual design features. A broad evaluation is conducted regarding energy-saving and environmental effectiveness, economic efficiency, cost-effectiveness, transaction costs, political feasibility, administrative burden and technical change. The results show the design and performance of TWC schemes to be case and context-specific, and generalisations are thus inappropriate. This evaluation supports the cost-effectiveness modelled for the British scheme and the assumption that a TWC scheme is an economically efficient policy instrument. For the other, more complex TWC schemes, more data and experience are needed to judge their ex-post merit. On the whole, the proposed multi-criteria evaluation requires considerable data and complementary methods. However, the framework improves the understanding of the broad effects and attributes of TWC schemes. It deals with various empirical and normative aspects that can be applied in their evaluation.     

Evaluation of the environmental impact of waste wood co-utilisation for energy production

The need for a practical, economic and environmentally sound solution for waste wood arises from the requirements for resource conservation and recent regulations. Co-firing with coal is a promising option for the thermal recycling of waste wood. The overall environmental impact caused by the co-utilisation of waste wood with coal was evaluated by using life cycle assessment as established by Society of Environmental Toxicology and Chemistry (SETAC) [A technical framework for life cycle assessment. Washington, DC: SETAC, USA; 1991, Guidelines for life cycle assessments: A code of practice. Brussels: SETAC, Europe; 1993]. This provides opportunities to evaluate direct environmental impact, to identify possible improvements, and to reduce energy resource consumption. In this work, the environmental impact of co-utilising lignite and waste wood in an industrial steam boiler was evaluated. Results obtained showed that co-utilisation is technically feasible and can meet strict environmental standards. A net decrease of CO₂ emissions can be achieved by the thermal use of waste wood, as well as conservation of fossil fuel resources, minimisation of waste disposal and reduction of impacts on health.     

Multi-objective optimization design and operation strategy analysis of BCHP system based on life cycle assessment

The promising energetic and environmental benefits of building cooling heating and power (BCHP) system are greatly dependent upon its design and operation strategy. In this paper, the energy and emission flows and different operation strategies of a BCHP system driven by gas engine are analyzed. Life cycle assessment (LCA) is employed to assess and compare the whole life energy saving potentials and pollutant emission reductions of BCHP system with the traditional energy system. Furthermore, energy consumption and three pollutant-related impacts, global warming, acid precipitation and respiratory effects, are selected as objective functions to optimize the gas engine capacity of BCHP system in different operation strategies. A numerical case of BCHP system for a commercial office building in Beijing, China is applied to obtain the optimum BCHP alternative in terms of the comprehensive energy and environment performance. The uncertainty of different evaluation criteria weights is also analyzed to show their influences on the optimal design and operation strategy. The results show that a reasonably sized BCHP system with an electric load-following strategy has the best performance under a wide interval of criteria weights, when the energetic and environmental benefits of producing excess electricity for nearby users are not considered.     

Suitable thermal insulation solutions for Mediterranean climatic conditions: a case study for four Greek cities

The selection of thermal insulation solutions has to satisfy many criteria: energy performance is the obvious one, structural and safety performance is a prerequisite, and environmental and economic aspects are those that can make the difference. However, especially when buildings operate under the Mediterranean climates, where outdoor conditions have to be mitigated by the building fabric throughout the year, the contribution of an insulation solution to indoor thermal comfort is also an important issue. In this approach, an integrated decision support system was applied to assess thermal insulation practices used commonly in residential buildings in the Mediterranean area. The system assesses the buildings’ elements over their life cycle, with thermal comfort being evaluated by means of the PMV/PPD index. Twenty-three thermal insulation configurations were considered, with different locations (internal, middle, external), materials (expanded polystyrene, extruded polystyrene, stone wool), and thicknesses. As the results showed, the position and the thickness of the insulation materials have a large impact on the energy consumption, the overall environmental impact, and the life cycle cost of the building, while thermal comfort was affected to a lesser degree.     

The complexity and challenges of determining GHG (greenhouse gas) emissions from grid electricity consumption and conservation in LCA (life cycle assessment) – A methodological review

The way in which GHG (greenhouse gas) emissions associated with grid electricity consumption is handled in different LCA (life cycle assessment) studies, varies significantly. Apart from differences in actual research questions, methodological choices and data set selection have a significant impact on the outcomes. These inconsistencies result in difficulties to compare the findings of various LCA studies. This review paper explores the issue from a methodological point of view. The perspectives of ALCA (attributional life cycle assessment) and CLCA (consequential life cycle assessment) are reflected. Finally, the paper summarizes the key issues and provides suggestions on the way forward. The major challenge related to both of the LCA categories is to determine the GHG emissions of the power production technologies under consideration. Furthermore, the specific challenge in ALCA is to determine the appropriate electricity production mix, and in CLCA, to identify the marginal technologies affected and related consequences. Significant uncertainties are involved, particularly in future-related LCAs, and these should not be ignored. Harmonization of the methods and data sets for various purposes is suggested, acknowledging that selections might be subjective.     

Performance analysis and modeling of energy from waste combined cycles

Municipal solid waste (MSW) is produced in a substantial amount with minimal fluctuations throughout the year. The analysis of carbon neutrality of MSW on a life cycle basis shows that MSW is about 67% carbon-neutral, suggesting that only 33% of the CO₂ emissions from incinerating MSW are of fossil origin. The waste constitutes a “renewable biofuel” energy resource and energy from waste (EfW) can result in a net reduction in CO₂ emissions. In this paper, we explore an approach to extracting energy from MSW efficiently – EfW/gas turbine hybrid combined cycles. This approach innovates by delivering better performance with respect to energy efficiency and CO₂ mitigation. In the combined cycles, the topping cycle consists of a gas turbine, while the bottoming cycle is a steam cycle where the low quality fuel – waste is utilized. This paper assesses the viability of the hybrid combined cycles and analyses their thermodynamic advantages with the help of computer simulations. It was shown that the combined cycles could offer significantly higher energy conversion efficiency and a practical solution to handling MSW. Also, the potential for a net reduction in CO₂ emissions resulting from the hybrid combined cycles was evaluated.     

Multi-criteria evaluation for the optimal adoption of distributed residential energy systems in Japan

Evaluation of sustainable residential energy system is complex process, in which not only the economic aspect, but also the energetic and environmental effects should be taken into consideration. In this paper, an integrated design and evaluation model has been developed, by combing linear programming and multi-criteria evaluation method, in order to determine the optimal residential energy system while considering different types of information. As an illustrative example, an investigation is conducted for a typical residential building in Kitakyushu, Japan. A set of residential energy alternatives, including both conventional energy and renewable energy applications, are assumed for adoption. Based on the optimal design results from the linear programming, the various alternatives have been assessed against economic, energetic and environmental criteria. According to the evaluation results, currently, renewable energy systems are not competitive unless strong attention is paid to the environmental benefits. All electric system may be a transitional consideration before reaching an actual low carbon residential energy system. Furthermore, the evaluation result is greatly influenced by the criteria priority, as well as the evaluation method.     

Life cycle assessment in buildings: The ENSLIC simplified method and guidelines

Life Cycle Assessment (LCA) is currently used to a very limited extent in the building sector, for several reasons. Firstly, making an LCA evaluation of a building demands a specific tool to handle the large dataset needed and this tool has to be adaptable to the different decisions taken throughout the life cycle of the building. Such tools have been developed in a few countries, but they are exceptions. However, useful experience has been gained in these countries, providing a valuable source of data for developing guidelines for application in other countries. Since the results of a building LCA may contain complex information, the great challenge is to devise efficient ways for communication of the results to users and clients.The simplified methodology presented in this paper adopt a systematic approach guiding the user through the Life Cycle process and clarifying key issues that usually cause difficulty, e.g. choice of assessment tool, definition of system boundaries, options for simplifying the process, etc. The guidelines were developed within the framework of the ENSLIC Building Project, which was co-funded by the European Commission Intelligent Energy for Europe Programme and by nine European organisations that included more than 15 LCA experts and architects.     

Life cycle assessment of stand-alone photovoltaic (SAPV) system under on-field conditions of New Delhi,India

In this paper, life cycle analysis has been carried out to evaluate overall performance of given rated stand-alone solar photovoltaic (SAPV) in terms of basic energy matrices, life cycle cost analysis, and earned carbon credit. Further, the experimentally calculated actual on-field life cycle performance results of existing outdoor SAPV system (i.e. almost 20 years old) have been represented with respect to the potential (max.) performance of same SAPV system estimated under same environmental conditions of solar intensity, ambient temperature, PV operating temperature as obtained during actual on-field performance evaluation. This new approach of overall performance evaluation by considering the on-field SAPV system installation as new (i.e. with potential/max. performance) and old (i.e. with actual performance) under same environmental conditions provides an inclusive comparative life cycle assessment of on-field PV system.     

Life cycle analysis of retrofitting with high energy efficiency air-conditioner and fluorescent lamp in existing buildings

Life cycle analysis of mercury in discarded low energy efficiency fluorescent lamps (36 W) and of HCFC in air-conditioners (12,000 Btu) removed from service has been conducted in this study. The objective was to find out the environmental impact (EDIP 1997 category, waste evaluation) of the products that appear in the waste stream as a result of facility upgrades. The scope of the study starts from retrofitting of the lamps and air-conditioners through recycling and disposal. For a 36 W fluorescent lamp, the bulk waste 1.64E−5 kg, hazardous waste 1.11E−4 kg, radioactive waste 1.09E−9 kg, and slag–ash 6.02E−7 kg occurred at the end of life of the retrofitting cycle. For a 12,000 Btu air-conditioner, the bulk waste 0.58 kg, hazardous waste 0.11 kg, radioactive waste 0.0002 kg, and slag–ash 0.01 kg also occurred at the end of life of the retrofitting cycle. These small amounts become important when viewed at the country level. These quantities imply that the policy makers who deal with hazardous waste should be aware of this waste-generating characteristic before issuing any pertinent policy. Consideration of this characteristic and planning for appropriate waste management methods at the beginning stage will reduce any future problem of contamination by the hazardous waste.     

Life cycle assessment of MSF,MED and RO desalination technologies

In this work, a comparison of the commonly deployed commercial desalination technologies worldwide—multistage flash (MSF), multieffect evaporation and reverse osmosis (RO)—is assessed by applying life cycle analysis (LCA). LCA, a powerful, and internationally accepted tool used to examine environmental cradle-to-grave consequences of making and using products and services, identifies and quantifies energy and material usage and waste discharges. The International Standard Organization (ISO) 14000 impact factors, which are internationally accepted standard indicators for environmental impact assessment, have been evaluated, and different evaluation methods (Centre for Environmental Studies (CML) 2 baseline 2000, Eco-Points 97 and Eco-Indicator 99) have been applied to different scenarios. The assessment includes the entire life cycle of each desalination process, encompassing extraction and processing raw materials, manufacturing, transportation and distribution, plant operation and final reject disposal.     

Life cycle assessment of a PPV plant applied to an existing SUW management system

The huge amount of wastes produced by modern and developed countries involves important aspects of economical, social and technical fields and also of the environment. For this reason, different technologies have been proposed for trying to reduce the impact of waste management and disposal. Generally waste management system consists of different steps like selective collection, recycling and reuse operation, energy recovery from waste and landfilling. A new technology proposed for thermal waste treatment is the plasma pyrolysis vetrification (PPV). This system seems to have interesting perspective due to the possibility of thermal treatment of dangerous slag or waste producing inactivate vetrified substances that can be landfilled or used as building materials with no impact on the environment. In this study, the effect of the application of a PPV plant on an existing waste management system was evaluated with a life cycle assessment (LCA) analysis. All the activities connected to the existing system have been carefully analysed by collecting a large quantity of experimental data. Some assumptions have been made, in particular, on the PPV plant performance. LCA analysis results illustrate how the environmental benefits arising from the adoption of the new technology, concerns only few aspects of the whole system. Copyright © 2003 John Wiley & Sons, Ltd.     

Evaluation of technical improvements of photovoltaic systems through life cycle assessment methodology

Since solar energy systems feed on a ‘clean’ energy source, they do not produce polluting emissions during their operation. However, they carry the environmental weight of other phases in their life cycle. In order to analyze the energy and environmental profile of these systems, it is necessary to expand the system boundaries, taking into account also the ‘hidden impacts’ related to production, transportation and system disposal at the end of its technical life. Here, the life cycle assessment methodology is applied to derive a complete and extended energy and environmental profile of photovoltaic systems. As reference case, a conventional multi-crystalline building integrated system is selected, retrofitted on a tilted roof, located in Rome (Italy) and connected to the national electricity grid. Then improved configurations of the reference system are assessed, focusing on building integration issues and the operational phase (considering an experimental hybrid photovoltaic system with heat recovery). Environmental ‘pay back times’ of the assessed systems are then calculated for CO₂ equivalent emissions and embodied energy. All the analyzed configurations are characterized by environmental pay back times one order of magnitude lower than their expected life time (3–4 years vs. 15–30 years). Thanks to a wider exploitation of photovoltaic potential during its ‘zero emission operation’, these results are further lowered by photovoltaic hybrid systems (environmental pay back times, depending on heat recovery configuration, go down to 40–50% of the values calculated for the reference case).     

Evaluation of PMSG‐based drivetrain technologies for 10‐MW floating offshore wind turbines: Pros and cons in a life cycle perspective

This paper presents an in depth evaluation and comparison of three different drivetrain choices based on permanent‐magnet synchronous generator (PMSG) technology for 10‐MW offshore wind turbines. The life cycle approach is suggested to evaluate the performance of the different under consideration drivetrain topologies. Furthermore, the design of the drivetrain is studied through optimized designs for the generator and gearbox. The proposed drivetrain analytical optimization approach supported by numerical simulations shows that application of gearbox in 10‐MW offshore wind turbines can help to reduce weight, raw material cost, and size and simultaneously improve the efficiency. The possibility of resonance with the first torsional natural frequency of drivetrain for the different designed drivetrain systems, the influence of gear ratio, and the feasibility of the application for a spar floating platform are also discussed. This study gives evidence on how gearbox can mitigate the torque oscillation consequences on the other components and how the latter can influence the reliability of drivetrain.     

Liquid metal activated hydrogen production from waste aluminum for power supply and its life cycle assessment

Hydrogen energy draws increasing concerns as a kind of renewable and clean energy. Liquid metal (LM) activated Al–H₂O reaction is recently emerging as an alternative for real-time hydrogen production. In this study, the energy consumption and environmental impact of this newly emerging method are evaluated via the life cycle assessment (LCA), which indicates that the utilization of waste Al could significantly relieve the energy and environmental issues. In addition, conceptual experiments were conducted to verify the feasibility of hydrogen generation from waste Al, and to disclose the hydrogen generation performances of Al samples in different forms. To balance the cost of LM and reaction efficiency, the optimum mass ratio of LM to Al were explored, and the reusability of LM was demonstrated. Further, a SWOT analysis is adopted to interpret the Strengths and Weakness of such hydrogen production method, and to evaluate the Opportunities and Threats it confronts. Overall, waste Al could provide an energy-saving and environmentally friendly approach to produce hydrogen, which is expected to exploit a new way towards the green hydrogen era.     

Modeling of phase change materials for applications in whole building simulation

The advanced buildings of tomorrow will need to take advantage of renewable, ambient and waste energy to approach ultra-low energy buildings. Such buildings will need to consider Thermal Energy Storage (TES) techniques customized for smaller loads.Recently, TES has attracted increasing attention due to the potential benefits it can deliver in energy efficiency, shift load from peak to off-peak, economics and environmental impact. Advanced design tools and technical improvements are required in TES technology and systems. Indeed the design of the building and the TES are often not coordinated. A building integrated with distributed thermal storage materials could shift most of peak load to off-peak time period.Even though various tools have been developed to model the behavior of applied phase change materials (PCM), unacceptable accuracy and/or high computational time are addressed as their major drawbacks. This implies that the development of a fast and reliable model is necessary in order to simulate the long-term behavior of these materials, especially for design and optimization.Therefore, a new and fast one-dimensional analytical model is proposed in this paper. The PCM behavior is modeled using a RC-circuit concept containing variable capacities for resistant and capacitor. In this approach, the length of mushy, solid, and liquid phases in each period of time signifies the RC capacity. In order to evaluate the performance of the proposed model, a computational fluid dynamics (CFD) model is then developed. The prediction of the newly developed model is compared with the prediction made by the CFD. There are good agreements between the predictions, and the results clearly show the high performance of the proposed model.     

LCAs of a polycrystalline photovoltaic module and a wind turbine

This study compares the environmental impacts of a polycrystalline photovoltaic (PV) module and a wind turbine using the life cycle assessment (LCA) method. This study models landfill disposal and recycling scenarios of the decommissioned PV module and wind turbine, and compares their impacts to those of the other stages in the life cycles. The comparison establishes that the wind turbine has smaller environmental impacts in almost all of the categories assessed. The disposal stage can become a major contributor to the environmental impacts, depending on disposal scenarios. Recycling is an environmentally efficient method, because of its environmental benefits derived from energy savings and resource reclaimed. The end-of-life recycling scenario for a wind turbine has a significant part on the environmental impacts and should not be ignored. However, many factors also influence the degree to which recycling can be beneficial. With the wind turbine recycling scenario, when large quantities of waste are recycled, the potential savings can be quite large, while with the PV module, small quantities of recycled waste mean that the benefits of recycling are not fully reaped.     

Review and comparison of various hydrogen production methods based on costs and life cycle impact assessment indicators

Hydrogen is a clean, renewable secondary energy source. The development of hydrogen energy is a common goal pursued by many countries to combat the current global warming trend. This paper provides an overview of various technologies for hydrogen production from renewable and non-renewable resources, including fossil fuel or biomass-based hydrogen production, microbial hydrogen production, electrolysis and thermolysis of water and thermochemical cycles. The current status of development, recent advances and challenges of different hydrogen production technologies are also reviewed. Finally, we compared different hydrogen production methods in terms of cost and life cycle environmental impact assessment. The current mainstream approach is to obtain hydrogen from natural gas and coal, although their environmental impact is significant. Electrolysis and thermochemical cycle methods coupled with new energy sources show considerable potential for development in terms of economics and environmental friendliness.