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Is the environmental opportunity of retrofitting the residential sector worth the life cycle cost? A consequential assessment of a typical house in Quebec
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... Many scholars have discussed the opportunities and barriers to adopting and implementing resilience and sustainability practices in the adaptation and retrofitting of existing buildings as well as new buildings in both developed and developing nations, but not many studies are context-specific. In the developed world, for example, Ahn et al. (2013), Bertone et al. (2018), and Hwang and Tan (2012) discussed the opportunities and barriers in the U.S., Australia, and Singapore, respectively, Lindkvist et al. (2014) discussed the barriers in Norway and Sweden, Haeyeon (2014) in Finland, andSunil (2012) in the U.K., and Miu et al. (2018) and Pedinotti-Castelle et al. (2019) studied the opportunities in the U.K. and Canada, respectively. In the developing world, Nikyema and Blouin (2020) explored the barriers and opportunities in Burkina Faso, Aktas, and Ozorhon (2015) in Turkey, and Serin Abraham and Gundimeda (2018) in India, while Masrom et al. (2017) explored the barriers to sustainable building retrofits and refurbishment in Malaysia. ...
... Social sustainability promises a more equitable and better quality of life (Karji et al., 2020), and therefore contributes to social resilience when sustainability is seen as a component of resilience and vice versa (Marchese et al., 2018). Enhancing social awareness is a solution to foster and promote sustainable construction (Ahn et al., 2013;Aktas & Ozorhon, 2015;Karji et al., 2020;Pedinotti-Castelle et al., 2019;Remøy & Van Der Voordt, 2014b) and sustainable construction can also be an opportunity through raising awareness of resilience and sustainability practices (Aktas & Ozorhon, 2015). According to Expert 7, people sometimes need to see something before they decide to invest in it, especially with regard to major sustainable building retrofit strategies that are unknown to many. ...
... Findings also highlight that although there are common obstacles between developing and developed countries, developing countries take the lead when it comes to the number and severity of barriers due to more economic, environmental, and social complications (Aktas & Ozorhon, 2015;Bertone et al., 2018;Bruce et al., 2015;Cassino et al., 2013;Hwang & Tan, 2012;Lindkvist et al., 2014;Nikyema & Blouin, 2020;Serin Abraham & Gundimeda, 2018). Barriers in developed countries are made up of financial obstacles, scarcity of available sustainable and resilient materials, time constraints, complicated building regulations, as well as the lack of professionals and local awareness (Ahn et al., 2013;Bertone et al., 2018;Bruce et al., 2015;Hwang & Tan, 2012;Pedinotti-Castelle et al., 2019). Developing countries face additional barriers such as poor infrastructure and the high level of non-compliance with building regulations, lack of cooperation between the different stakeholders involved in sustainable and resilient retrofit work, lack of sustainable and resilient building regulations and codes in the case of adaptation and building retrofits, and lastly, the lack of financial support and incentives provided by governments (Aktas & Ozorhon, 2015;Nikyema & Blouin, 2020;Serin Abraham & Gundimeda, 2018). ...
Today's hazards and stressors threaten individuals, infrastructure, and buildings - all of which become 'vulnerable' when they lack the resilience to cope, adapt, and recover. With emerging global challenges, including severe natural disasters, conflicts, and resource shortages, greater resilience is needed than ever before. Globally, very little work has been conducted on buildings in contrast to the urban level and none in Jordan. This research aims to contribute to the understanding of what defines resilience at the level of buildings in Jordan, based on its complex socio-ecological resilience challenges and increasing building retrofits. The thesis used an exploratory research design employing multiple methods: 1) mainly qualitative, including literature reviews, policy analysis, questionnaires targeted at local experts, interviews and focus groups, and case study analysis of real-world building retrofits; 2) quantitative, including the word-frequency method of analysis of relevant policy and literature. The study first explored how to define resilience at both the urban and building level, and then identified and established a deeper understanding of Jordan's key shocks and stressors and examined relevant policies. It then investigated the increasing trend in Jordan of retrofitting existing buildings and identified challenges and opportunities around resilience. In addition, it presented several multi-hazard resilient strategies for existing building retrofits, investigated their implementation in a wide range of real-world case studies in Jordan, and validated their applicability with local experts. The outcome(s) of this work revealed that achieving resilience requires substantial changes in policymaking and resource management, with the participation of both government and non-government organisations, to establish a solid policy and technical, and socio-ecological infrastructure that can drive multi-hazard resilience-thinking in building retrofits. The research demonstrates that, although some efforts exist in Jordan to include resilience in policy and building retrofit practices, progress has been gradual and slow due to a lack of clarity about how resilience is employed and interpreted in 'action'. This study shows that there is a good potential for implementing resilient building retrofits with several locally applicable strategies. It establishes a foundation that assists policymakers in developing future multi-hazard building retrofit guidelines to be used in the building industry in Jordan and beyond. Keywords Multi-hazard resilience; Resilient buildings; Jordan; Retrofitting for resilience; Resilience strategies.
... LCA + LCC are applied to answer a wide range of questions, from the determination of payback periods for energy retrofits [47], finding optimal solutions for one building part (e.g., insulation thickness [51]) to optimizing an entire design space [58,64] or a group of building types [45]. Prevalent topics are the implications of LCA + LCC for retrofit solutions [6,48,55,61,67,69,73] and the trade-offs between environmental and economic considerations in building design [45,49,65,69]. ...
... Any systems which are the same for all options can be excluded, as they are irrelevant to the relative comparison. For instance, some studies are limited to the building skin [52,53,59,61,67,80] or a part of it [65], as they consider its influence on operational energy use, but not on other building systems. However, limited system boundaries miss information on the relevance of the study scope. ...
... Two studies include appliances [47,51] and eight studies include energy-related systems. Six of these studies include the respective embedded environmental impacts [6,8,45,54,64,67], whereas two studies include building systems only in LCC calculations [58,69]. In general, very little information is provided on the systems included or variations thereof. ...
With increasing environmental damage and decreasing resource availability, sustainability assessment in the building sector is gaining momentum. A literature review shows that the related methods for environmental and economic performance, Life Cycle Assessment (LCA) and Life Cycle Costing (LCC), show great potential for answering a multitude of questions related to building performance. Prevalent topics are the implications of LCA and LCC for retrofit solutions and the trade-offs between environmental and economic considerations in building design. A detailed review of 30 case studies shows the range of differing result integration methods and sheds light on the use of monetary valuation of environmental indicators for an integrated assessment. While a quasi-dynamic approach, accounting for the changing value of money over time, is common in LCC, such an approach is largely absent from LCA. The analysis of common metrics shows that the studies employ strongly differing system boundaries and input parameters. Moreover, a clear description of the methodological framework is missing in most studies. Therefore, this research develops an “Eco2” framework, integrating LCA and LCC for application in building design. Potential further developments for Eco2 building assessment are related to extending the system boundaries by including mechanical systems and end-of-life phases, data collection and structuring, and streamlining the approach for continuous application to all stages of building design processes. Additionally, the influence on design decisions of employing temporal parameters in both LCA and LCC and of choosing particular result integration methods should be investigated further.
... In fact, contemporary approaches to support design decision-making already consider properly balanced costs and environmental impacts over the lifespan, together with functional requirements (Wang et al., 2010;Oliveira et al., 2013Rohden & Garcez, 2018Pedinotti-Castelle et al., 2019). Thus, despite not being originally developed in an environmental context, LCC has been used as an economic sustainability indicator (Ahmad & Thaheem, 2018) applied to quantify the costs of whole buildings, systems, and/or components and materials. ...
... Wang et al. (2010) report that energy consumption related to building construction and operation accounts for almost half of the annual energy consumption in China. Heating and cooling represent 40% of energy consumption in Canadian buildings (Pedinotti-Castelle et al., 2019). In a global level, buildings and construction industry consumed about 36% of the total final energy use in 2016, according to the UN Environment and IEA (2017) program towards a zeroemission, efficient, and resilient buildings and construction sector. ...
This paper aims at contributing to the dissemination of Life Cycle Cost as a management tool to face current construction market challenges in terms of economic performance. Recent developments, methodology, advantages, weaknesses, and potential benefits of performing an LCC analysis are presented and discussed. A simplified case study illustrates detailed economic performance calculations for a hypothetical office building whose results presented in Net Present Value are discussed and complemented with case studies reported in the literature. Operation costs related to electric energy consumption for heating and cooling are commonly the main contributors to the LCC of buildings, followed by maintenance costs, which evidences the need to equate costs and energy efficiency, especially to meet the objectives of a sustainable construction market. LCC plays an important role in minimizing costs throughout building's lifespan when performed in the building design phase.
... Gross energy use kWh [37] (over 50 year life), [44], [45], [47], [48], [53], [55], [57], [58], [59], [86], [90], [98], [99], [103], [106], [108], [109], [111], [118], [120], [125], [126], [127] [29], [35], [42], [45], [48], [60], [85], [88] (district heating), [113], [125], [126] [53], [90] [76], [103] (one summer/one winter week) ...
... Energy demand kWh/m 2 (often representing heating and/or cooling demand) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 30 J/m 2 [32], [36], [112], [115] Emissions Kg CO2-e [53], [88], [111], [126], [124] Kg CO2e/m 2 [53], [67], [69], [73], [112], [121] ...
The existing residential building stock accounts for a substantial portion of worldwide energy consumption and greenhouse emissions. Improvements to the thermal performance of existing buildings is a vital activity to mitigate climate change, and often has additional benefits in the form of improved comfort, health and well-being for occupants. Despite the extensive body of literature in this area, it remains a difficult task to assess the performance of retrofit packages in occupied residential buildings. Experimental methods often fail to isolate the effect of retrofits from the numerous confounding factors, while modelling studies are prone to uncertainties and simplifications. The aim of this paper is to provide a critical review of previous studies that have applied experimental and simulation techniques to evaluate thermal retrofits, with a focus on data collection and simulation methods. Specifically, we compare monitoring campaigns in terms of monitored parameters, duration of monitoring campaign, temporal resolution and data application. Additionally, we investigate how data-driven building performance simulation may be used to improve predictive capacity and develop robust retrofit solutions. We identified a range of approaches within the literature, with a bias towards simulating simple performance models over detailed data-driven analysis. A recommendation is provided for a systematic approach that employs both intensive monitoring campaigns and robust prediction methods to improve retrofit evaluation, and support assessment of the reliability and shortcomings of evaluation data.
... Promising to keep the global temperature rising to 1.5 0 C above the preindustrial levels, is one of the major outputs of the 2015 United Nations Paris Agreement (Shubbar et al. 2021). As a result, strong measures are required for decarbonization to keep the global temperature rise to 1.5 0 C (Pedinotti-Castelle et al. 2019). However, the energy crisis and climate change continue to be major issues for humanity's development worldwide (Ascione et al. 2020;Assimakopoulos et al. 2020;Toufeili et al. 2022). ...
Carbon emission is a huge challenge for the world to combat climate change and achieve the Paris Agreement targets. To address this challenge, it is important to retrofit existing buildings towards net zero carbon (NZC). Many studies have focused on different aspects of building retrofitting towards NZC. However, a study that systematically examines the knowledge domain of building retrofitting towards NZC is lacking. This study aims to analyze the existing research domain of NZC retrofitting through a bibliometric analysis and provide pathways for future research. Based upon 517 relevant articles identified from Scopus, bibliometric analysis was conducted using the VOSviewer and Gephi software tools. Findings revealed the collaboration networks between authors, countries, organizations, and keywords in this research domain. R.F. De Masi and G.P. Vanoli are the two authors with the highest link strength, while the University of Naples Federico II has the highest number of NZC retrofitting publications. In addition, Italy is the country with the highest number of publications, but China is the most productive country when it comes to both publications and citations combined. "Energy efficiency", "energy saving", "nearly zero energy building", "net zero energy", and "renewable energy" are the most prioritized research areas. Based on identified gaps, future research directions are proposed to include (1) integration of modern technology to simulate NZC retrofitting; (2) optimization of sustainable measures to achieve NZC buildings; and (3)quantification of drivers and benefits of NZC retrofitting. The findings of this study would be useful to researchers, policymakers, and practitioners who are interested in NZC retrofitting.
... Likewise, inclusion of pre-1960 construction may provide more nuanced detail, especially as research comparing the impact of new construction with renovation of the existing built environment may yield useful insights in Montreal. While this study only accounts for new construction, many have shown the importance of considering refurbishment of the built environment [71,72]. Further investigation into the turnover rate of Montreal's current built form and dwellings more suitable to refurbishment than replacing may yield variations in the results shown here. ...
Engineered wood (EW) has the potential to reduce global carbon emissions from the building sector by substituting carbon-intensive concrete and steel for carbon-sequestering wood. However, studies accounting for material use and embodied carbon in buildings rarely analyze the city-scale or capture connections between the city and supplying hinterlands. This limits our knowledge of the effectiveness of decarbonizing cities using EW and its potential adverse effects, such as deforestation. We address this gap by combining bottom-up material accounting of construction materials with life cycle assessment to analyze the carbon emissions and land occupation from future residential construction in Montreal, Canada. We compare material demand and environmenetal impacts of recent construction using concrete and steel to construction using EW at the neighborhood, urban scales under high- and low-density growth scenarios. We estimate that baseline embodied carbon/capita across the Agglomeration of Montreal is 3.2 tonnes/carbon dioxide equivalents (CO2eq.), but this ranges from 8.2 tonnes CO2eq./capita in areas with large single-family housing to 2.0 tonnes CO2eq./capita where smaller homes predominate. A Montreal-wide transition to EW may increase carbon footprint by up to 25% under certain scenarios, but this varies widely across the city and is tempered through urban densification. Likewise, a transition to EW results in less than 0.001% land transformation across Quebec’s timbershed. Moreover, sustainable logging practices that sequester carbon can actually produce a carbon-negative building stock in the future. To decarbonize future residential construction, Montreal should enact policies to simultaneously promote EW and urban densification in future construction and work with construction firms to ensure they source timber sustainably.
... Policy information studies compare various options for obtaining a policy goal. Pedinotti-Castelle et al. (2019) illustrate this by evaluating whether retrofitting the residential sector would improve the environmental and economic impacts more than installing new power plants to replace fossil-fuel energy sources. All four policy information studies have buildings as their assessment target, while the policy development studies are distributed among eight material-and seven building-oriented studies. ...
Purpose
The built environment has demonstrated the limited nature of applications of consequential LCA (LCA), whereas attributional LCA (ALCA) is applied in most situations. Therefore, this study aims to clarify the contexts in which CLCA might be applied and the state of CLCA on buildings by examining the following research questions: (i) How are the goal, scope and methodological aspects and associated gaps of CLCA of buildings addressed in the literature? (ii) How can these insights guide the applications of CLCA on buildings?
Methods
The study employed the Systematic Literature Review methodology, which yielded 37 relevant studies. The study examined the sample regarding intended applications, the contexts of micro or meso/macro decision-making support, and the consequential life-cycle inventory modelling (CLCI) of time horizons, market delimitations, market volume trends, affected suppliers, constrained supplies and substitution. Furthermore, the basis for choosing either an ALCA or a CLCA approach was evaluated based on the ILCD Handbook.
Results and discussion
Many studies include an empirical assessment, yet with half of those combining it with an evaluation of selected methodological aspects, thus CLCA on buildings seems to still be in the earlier exploration phase. In general, the empirical CLCAs emphasize the decision-making aspect in the stated application of the study. Furthermore, CLCA studies show an almost equal distribution of focus between the micro and meso/macro levels of decision support. This entails that CLCA on buildings currently applies to both material- and building-level assessments and policy situations. The inclusion of CLCI modelling elements varies: e.g., nine studies only include substitution as the single CLCI element. Additionally, modelling methods are described at various levels of detail, and with critical differences in the transparency of documentation. This, therefore, suggests that the consistency of included CLCI elements is inadequate, as is how they should be modelled.
Conclusions and recommendations
Building on the ILCD Handbook, this study presents a proposal for deciding when to select CLCA on buildings. This is a proposal for a simple and clear distinction threshold between the micro and meso/macro levels. Additionally, CLCA on buildings need a more harmonized approach to CLCI modelling to increase and improve, which the built environment community could achieve by settling on a standard for the inclusion of CLCI elements and associated modelling methods.
... This work showed that the net energy produced with a repurposed 1500 m well (Scenario A) and the best configuration (HDPE-A) is around 15 990 MWh over 30 years of continuous operation at its optimal fluid flow rate (2 L s − 1 ). This corresponds to the heat consumption of 21 average households over 30 years in southern Québec, based on the average energy consumption provided in Pedinotti-Castelle et al. (2019). If a 3000 m deep well is available, a maximum of 28 780 to 36 300 MWh of net energy could be produced over 30 years depending on the length of the casing (1000 or 2000 m) and choice of the inner pipe. ...
Heating performance of deep borehole heat exchangers (DBHEs) is heavily impacted by its design and operating flow rate. Here, various designs of coaxial DBHEs were numerically simulated and compared for 1 year of continuous operation in a cold sedimentary basin using the FEFLOW software. Factors affecting performance, including: (1) depth, (2) repurposing an oil and gas (O&G) well or drilling a larger one, (3) repurposing options, (4) inner pipe material, made of either vacuum insulated tubing (VIT) or high-density polyethylene and (5) grout with different thermal conductivity were evaluated. Where an O&G well is available, the most cost-efficient option is repurposing, with the best performance obtained from the deepest and largest diameter wells. While VIT inner pipes performed better in some designs, their performance did not compensate for their cost.
... In addition, economic feasibility analysis and risk assessment are important to comparing the different retrofit alternatives [16] and selecting the most preferable option among them [32]. While the bottleneck of retrofitting existing residential building rest with the owners as a result of the high up-front cost [7], studies have demonstrated that suitable retrofit measures can lead to a significant improvement in energy and environmental performance including reasonable economic return [10,33]. For instance, upgrading single glazing to double or triple glazing for single-family housing is beneficial to energy reduction in all climatic zones in the United States, irrespective of the window orientations and sizes [34]. ...
Sustainable building retrofit can provide a great opportunity to reduce the energy consumption of existing buildings to commensurate the climate policies and enhance the building energy performance. Given it strategic importance, there is no shortage of research studies on sustainable building retrofit globally in particular the retrofit measures and technologies for different types of buildings. Despite that, sustainable building retrofit is climate and location specific, and decision-makers are still facing challenges to identify an optimum set of retrofit measures for different climatic conditions according to the trade-off between energy saving and retrofit cost. One reason for that is because of the lack of available information especially those related to the cost of sustainable building retrofit measures. This study aims to develop an integrated energy-cost model for selecting the optimal retrofit solutions for existing high-rise residential buildings in various climatic zones in China. Based on in-depth literature review and analysis of published reports, different alternative retrofit measures for wall, window, shading system, heating and cooling systems, and renewable energy technologies for buildings in different climate zones of China are identified. The retrofit costs related to the identified sustainable building retrofit measures are analyzed by referring to the local renovation techniques and cost in each zone through developing a set of equations. A total 28 practical sustainable building retrofit measures along with a set of retrofit options are identified. A deterministic decision framework is developed to facilitate decision-makers achieving a specific energy saving target and evaluating the associated costs based on the identified retrofit measures for high-rise residential buildings in the studied climatic zones. The practical implications of the deterministic decision framework are examined through the prototype buildings in climatic zones being studies. The findings not only actively support the selection of cost-effective sustainable retrofit measures for high-rise residential buildings in China, but the methodological framework and its implications are also equally applicable to other countries with diverse climatic characteristics and standards of living.
... Finally, economic factors strongly affect policy decisions. Thus, having CLCC as a part of assessment is highly desired, especially the positive externalities often are not internalized [84]. By expanding system boundary to focusing the study to the consequences expected to be the most important, CLCC could bring more insights to have a comprehensive assessment. ...
Buildings are accountable for much of the resource consumption and CO2 emissions generated from human activities. Nonetheless, the focus of building life cycle assessment (LCA) studies to evaluate the environmental footprint are more commonly adopted in an attributional approach. Nevertheless, understanding a direct and indirect consequences in larger system using consequential approach is also needed for policy-making. Rather small body of existing literature has been found on the implementation of consequential LCA and life cycle costing (LCC) in the building sector. In this study, attributional and consequential approach are performed for hybrid wood multistorey building. The results showed that with attributional approach, the phase that contributed the environmental impacts the most in climate change category is the production phase yet it became the use phase if consequential approach is used. By performing consequential LCA-LCC the possible hidden impacts can be uncovered and sufficient insights into the indirect impacts can be seen, thereby offering stakeholders the opportunity to avoid such future consequences.
... Zheng et al. (2019a) conducted a similar building energy study based on a techno-economic-risk analysis. Previous studies indicated that multi-criteria decision-making and multi-objectives optimization methods have been used to determine optimal retrofit strategies (He et al., 2019;Zheng et al., 2019b), with economic feasibility analysis (Menassa, 2011) and risk assessment (Ascione et al., 2019b) also used to select the most preferable sustainable retrofit strategy (Pedinotti-Castelle et al., 2019). All enable a significant improvement in energy and environmental performance and economic revenue caused by reduced energy cost (Zheng et al., 2019a). ...
Sustainable building retrofitting has attracted serious research attention in recent years as it can significantly reduce energy consumption and thus help achieve energy reduction targets set by governments around the world. In this paper, a sustainable retrofit decision-making model is developed to uncover the optimal set of retrofit solutions according to local climatic conditions, building features, and retrofit costs. Net present value (NPV), a common method for analyzing the feasibility of a building retrofit solution, is used to determine the optimal retrofit solution of existing high-rise residential buildings in a temperate zone and hot summer-cold winter zone, involving prototypical 1990s apartments of 116 and 53 m2 floor areas respectively. This reveals that the lighting system, wall insulation, and upgraded window glazing are essential optimal retrofit measures for the temperate zone, whereas the heating system and shading devices are also essential for the hot summer-cold winter zone. The results indicate that the optimal NPV can be obtained by pursuing a 40% energy saving, as it can result in energy saving of up to 50 kWh/m2/year and 95 kWh/m2/year at an average retrofit cost of approximately USD 1.30 and 3.20 m2/year in the temperate and hot summer-cold winter zones respectively. The sensitivities associated with the most influential optimal NPV and energy savings input parameters are critically analyzed; these can be used by decision-makers to determine the risks and uncertainties related to various cost-effective retrofit measures. The model can help in devising the most suitable sustainable retrofit measures for existing buildings commensurate with the energy reduction targets of policy and decision-makers in the two climate zones. It is also amenable to being adapted for other climatic zones to identify the most appropriate sustainable building retrofit for particular local climatic conditions and building characteristics.
... On the other hand, economic feasibility analysis (Liu et al., 2018) and risk assessment have also been employed to compare different retrofit alternatives (Ascione et al., 2019b) and select the most preferable retrofit options (Menassa, 2011). While the high upfront cost restricts the owners from retrofitting existing residential buildings (Pardo-Bosch et al., 2019), several studies have demonstrated that suitable retrofit measures can lead to significant improvement in energy and environmental performance including reasonable economic return (Mata et al., 2019;Pedinotti-Castelle et al., 2019). Based on the life-cycle cost and Monte Carlo analysis, a model for screening multiple energy retrofit measures package was developed (Zheng et al., 2019b), and a similar study was conducted by Elisa (2019). ...
Considering the significant consumption of energy in existing building stocks, effective retrofitting has great potential for reducing such consumption and promoting sustainability in existing buildings. This study aims to develop a sustainable retrofit decision-making mechanism for high-rise buildings in Hong Kong, China, by uncovering the optimum set of retrofit solutions based on the local climatic conditions, building features and cost. Based on a prototype building in Hong Kong, the study employed the net present value (NPV) to unveil the most suitable solutions to maximise the energy efficiency of existing buildings and minimise their retrofit costs, integrating the energy simulation. This study revealed that it is desirable to adopt an optimal set of measures for achieving a 40% energy improvement since the energy conservation can be as much as 82 (kWh/m²)/year with the optimal NPV of more than US$3300 over a 20 year life span. However, the cooling system, building energy management system and thickness of wall insulation are the most influential factors to the optimum NPV and energy conservation in Hong Kong. The identified optimal set of cost-effective retrofit measures can be effectively implemented for sustainable retrofit projects in the existing building, and the developed methodological framework can be suitably adapted for sustainable building retrofit projects in different climatic zones. The decision-making model is validated by the process of calculating energy consumption, selecting practical retrofit measures and analysing retrofit benefits when taking the local building standards into account.
... A life cycle assessment of the sustainability and cost-effectiveness of different types of deep retrofits in the residential sector in Quebec, Canada is described in [61]. Several retrofit measures including ASHP installation, and a combined scenario with improved insulation and ASHP are reviewed. ...
The electrification of home heating is proposed as a low carbon solution in climate change action plans. It is therefore important to understand the energy efficiency and capability of heat pumps when deployed in the homes of end users. This paper presents a systematic literature review of Air Source Heat Pumps (ASHP) field studies. The papers are reviewed with respect to the field study focus, and analysed in terms of the field study design, and the analysis methodologies applied to the gathered data. The review finds three main areas of focus: defrosting management, ASHP system management, and ASHPs as smart grid demand response components. The review also identifies what ASHP data is publicly available to assist other researchers in building, testing and analysing ASHP efficiency models. Finally, future research topics on the use of ASHPs in home heating are identified.
... The optimum insulation thickness value is assessed through the life-cycle cost analysis (LCCA), a useful economic assessment tool to achieve sustainable objectives that lead to better long-term performance of the building with lower operating costs [36,37]. In the past few decades, this method has been widely used because it allows to make rational and accurate decisions, also in the building retrofitting field [38]. This systematic approach, used to optimize the thermal thickness, takes into account local weather conditions, fuel price, heating system efficiency and characteristics of the building. ...
The enhancement of energy performance of historic buildings is not a completely resolved theme because both the tools and European directives available to the designer are mainly designed to meet the needs of the new buildings. To improve the energy efficiency of this buildings built without technical installations and designed to exploit the climatic characteristics and local resources, it is necessary to investigate the key parameters that constitute the building envelope. This study presents a multidisciplinary approach allowing to compare the optimum insulation thickness determined from the transmittance values of historical walls measured in situ with the one calculated through literature data. In detail, the methodology includes a preliminary analysis of the historical envelope needed to carry out the in situ measurements of the thermal transmittance and an analysis of insulation material and its thickness to determine the optimal combination between the energy performance of the building and the investment cost for thermal insulation and environmental impact through the life-cycle cost analysis. After applying the methodology to a case study located in Italy, the results revealed that the exclusive use of literature data for the preparation of an energy recovery project for an existing historic building can lead to significant errors.
Egg production is amongst the most rapidly expanding livestock sectors worldwide. A large share of non-renewable energy use in egg production is due to the operation of heating, ventilation, and air conditioning (HVAC) systems. Reducing energy use, therefore, is essential to decreasing the environmental impacts of intensive egg production. This review identifies market-ready alternatives (such as heat pumps and earth–air heat exchangers) to traditional HVAC systems that could be applied in the industrial egg sector, specifically focusing on their use in temperate and continental climates. For this analysis, energy simulations were run to estimate the typical thermal loads of caged and free-run poultry housing systems in various Canadian locations, which were used as examples of temperate and continental climates. These estimations were then used to evaluate alternative HVAC systems for (1) their capability to meet the energy demands of egg production facilities, (2) their environmental impact mitigation potential, and (3) their relative affordability by considering the insights from a systematic review of 225 relevant papers. The results highlighted that future research should prioritize earth–air heat exchangers as a complementary system and ground source heat pumps as a stand-alone system to reduce the impacts associated with conventional HVAC system operation in egg production.
Operational energy use in buildings, accounts for 28% of global energy demand. One method to reduce operational energy is upgrading old appliances to more efficient ones. In Australia, the most common residential heating type is reverse-cycle heating, followed by gas heating. This research paper aims to determine the energy balance resulting from a gas heating upgrade through a life cycle assessment (LCA). Extensive primary data was collected for operational energy performance of 61 ducted gas heating upgrades. To address the scarcity of data on material composition, one ducted gas heater was deconstructed and assessed in terms of material composition (types and weights). The comparison between embodied energy and operational energy savings allows us to establish whether operational energy savings offset the embodied energy
incurred with the upgrade. The end of life stage of the old appliance, as well as the production, construction and use stage of the new appliance were assessed. Results show that operational energy savings offset the following impact categories: global warming, ozone layer depletion, aquatic acidification, non-renewable energy, and carcinogens. Only the mineral extraction is not offset by the operational energy savings.
Results clearly demonstrate that operational energy savings outweigh the embodied energy and therefore contribute positively to the environment. This study is the first to focus on the LCA of building services through extensive primary data collection and a focus on a high number of appliances. This supports ongoing energy efficient upgrades in Australia and pave the way for further, similar studies to confirm or disprove these
findings in other parts of the world.
To achieve the new European targets concerning CO2 emission reduction, the concept of a post-carbon city has been promoted, which is focused on low-energy and low-emission buildings provided with intelligent heating and cooling systems, electric and hybrid cars, and better public transport. This paradigm entails the inclusion of aspects not strictly related to energy exploitation but referring to environmental, social, and economic domains, such as improvement in local en-ergy security, people’s opinion on different energy solutions, economic co-benefits for private us-ers, environmental externalities, and so on. In this domain, it is of particular importance to pro-vide the decision makers with evaluation tools able to consider the complexity of the impacts, thus leading to the choice of the most sustainable solutions. The paper aims to investigate the sci-entific literature in the context of evaluation frameworks for supporting decision problems relat-ed to the energy transition. The review is carried out through the scientific database SCOPUS. The analysis allows for systematizing the contributions according to the main families of evaluation methodologies, discussing to what extent they can be useful in real-world applications. The paper also proposes emerging trends and innovative research lines in the domain of energy planning and urban management. While the energy transition is an important trend, the analysis showed that few studies were conducted on the evaluation of projects, plans, and policies that aim to reach post-carbon targets. The scales of application refer mainly to global or national levels, while few studies have been developed at the district level. Life cycle thinking techniques, such as life cycle assessment and cost–benefit analysis, were widely used in this research field.
Reduction of energy for space heating through retrofit interventions is imperative to meet carbon reduction targets in many temperate climates. A Life Cycle approach to retrofit design has the potential to reveal the balance between projected operational energy savings, and embodied energy invested in an intervention, and therefore optimise the extent of retrofit. However, life cycle energy analysis (LCEA) suffers from inconsistent methodologies across studies, and is rarely used for retrofit projects. A preliminary meta-analysis was conducted, drawing on LCEA data from domestic new builds and retrofits from the last twenty years. Whilst recent literature conversations indicate that embodied energy increases with decreasing operating energy, the meta-analysis is inconsistent with this. This review critiques the limitations and sources of variation in LCEA, focuses on how these compromise its value as part of the building design process and when comparing between projects, and recommends approaches which add value for building designers. This review has identified a need for research to elucidate a transferrable approach for determining the lowest life cycle energy for any retrofit, and also a need for a more robust data set of domestic retrofit LCEA.
The inclusion of temporal aspects in the environmental assessment of complex socio-technical systems is crucial. For power systems, such considerations allow computing the environmental impacts related to demand-side management strategies which could not be assessed with static data, such as temporal shifts of part of the demand from one period of the day to another. Several life cycle assessment (LCA) studies have included temporal aspects, but mostly regarding the system's production function. The consumption side of a socio-technical system, however, is also prone to fluctuate in time and its misrepresentation may lead to additional errors. In this study, the residential power demand of a set of Canadians' homes was modeled with a stochastic approach. Then, three different LCA approaches are compared: the use of an average or a marginal electricity mix and a combination of the two. The influence of the temporal granularity of data (yearly average or hourly data) on LCA results was also investigated. The case study of a simple demand-side management strategy illustrates the method. Results show that the assumption of a constant demand leads to errors regarding environmental impacts assessment, which may be as high as 136% depending on the period of the year assessed. Moreover, the wrong assumption regarding the nature of power demand leads to sub-optimal results for demand-side strategy: the use of an average electricity mix slightly increases greenhouse gas emissions, whereas applying a marginal mix decreases emissions by 10%.
Current anthropogenic climate change is the result of greenhouse gas accumulation in the atmosphere, which records the aggregation of billions of individual decisions. Here we consider a broad range of individual lifestyle choices and calculate their potential to reduce greenhouse gas emissions in developed countries, based on 148 scenarios from 39 sources. We recommend four widely applicable high-impact (i.e. low emissions) actions with the potential to contribute to systemic change and substantially reduce annual personal emissions: having one fewer child (an average for developed countries of 58.6 tonnes CO2-equivalent (tCO2e) emission reductions per year), living car-free (2.4 tCO2e saved per year), avoiding airplane travel (1.6 tCO2e saved per roundtrip transatlantic flight) and eating a plant-based diet (0.8 tCO2e saved per year). These actions have much greater potential to reduce emissions than commonly promoted strategies like comprehensive recycling (four times less effective than a plant-based diet) or changing household lightbulbs (eight times less). Though adolescents poised to establish lifelong patterns are an important target group for promoting high-impact actions, we find that ten high school science textbooks from Canada largely fail to mention these actions (they account for 4% of their recommended actions), instead focusing on incremental changes with much smaller potential emissions reductions. Government resources on climate change from the EU, USA, Canada, and Australia also focus recommendations on lower-impact actions. We conclude that there are opportunities to improve existing educational and communication structures to promote the most effective emission-reduction strategies and close this mitigation gap.
PurposeThis study aims at accounting for the variation in electricity production, processes and related impacts depending on season (heating, cooling), day of the week (tertiary building) and hour of the day. In this context, this paper suggests two alternative methods to integrate grid-building interaction in life cycle assessment of buildings and districts. Methods
An attributional dynamic method (AD) and a marginal dynamic method (MD) are compared with an annual average method (AA), representative of standard practice, using electric space heating as an illustrative case. The different methods are based on a dispatch model simulating electricity supply on an hourly basis, averaging historically observed climatic and economic variability. The meteorological inputs of the model are identical to those of the building energy simulation. Therefore, the environmental benefits from smart buildings and onsite renewable energy production are more accurately evaluated. Results and discussionUsing electricity production (or supply) data for a specific past year is a common practice in building LCA. This practice is sensitive to economic and meteorological hazards. The suggested methodology is based on a proposed reference year mitigating these hazards and thus could be seen as more representative of average impacts. Depending on the chosen approach (average or marginal) to evaluate electricity supply related impacts, the carbon footprint of the electric space heating option for the studied low-energy house in France is evaluated to 61.4 to 84.9 g CO2eq kWh−1 (AA), 78.8 to 110.2 g CO2eq kWh−1 (AD) and 765.1 to 928.7 g CO2eq kWh−1 (MD). Compared to wood and gas boiler, 22–107 and 218–284 g CO2eq kWh−1 respectively, the ranking between the different technical options depends on the chosen approach. Uncertainty analysis does not undermine the interpretation of the results. Conclusions
The proposed electricity system model allows a more precise and representative evaluation of electricity supply related impacts in LCA compared to standard practices. Two alternative methods are suggested corresponding to attributional and consequential LCA. The approach has to be chosen in line with the assessment objectives (e.g. certification, ecodesign). Prospective assessment integrating long-term evolution of the electric system and influence of global warming on buildings behaviour are identified as relevant future research subjects.
PurposeA systematic comparison is made of attributional and consequential results for the same products using the same unit process database, thus isolating the effect of the two system models. An analysis of this nature has only recently been made possible due to the ecoinvent database version 3 providing an access to both unallocated and unlinked unit process datasets as well as both attributional and consequential models based on these datasets. The analysis is therefore limited to the system models provided by ecoinvent. Methods
For both system models, the analysis was made on the life cycle inventory analysis (LCIA) results as published by ecoinvent (692 impact categories from different methods, for 11,650 product/activity combinations). The comparison was made on the absolute difference relative to the smallest absolute value. Results and discussionThe comparison provides quantified results showing that the consequential modelling provides large differences in results when the unconstrained (marginal) suppliers have much more/less impact than the average, when analysing the by-products, and when analysing determining products from activities with important amounts of other coproducts. Conclusions
The analysis confirms that for consequential studies, attributional background datasets are not appropriate as a substitute for consequential background. The overall error will of course depend on the extent to which attributional modelling is used as part of the overall system model. While the identified causes of differences between the attributional and consequential models are of general nature, the identified sizes of the errors are specific to the way the two models are implemented in ecoinvent.
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Purpose
Electricity is one of the main contributors to global environmental impacts, and its role as an energy carrier is expected to grow substantially. Consequently, reliable and accurate inventories of material and energy flows associated with electricity supply are essential in environmental assessments. This article aims to summarize existing challenges and opportunities in the modeling of life cycle inventories (LCIs) of electricity supply from a data quality perspective.
Methods
We systematically review the state-of-the-art in LCI modeling of current and future electricity supply worldwide. The analysis is structured according to the data quality characteristics proposed in ISO 14044: 2006: representativeness, completeness, consistency, reproducibility, uncertainty, data sources, and precision.
Results and discussion
Looking at existing LCIs through the lens of data quality, we observe difficulties in obtaining temporally and technologically representative data, while geographically representative data is still unavailable for some regions. Moreover, meta-analyses encountered issues of reproducibility combined with a lack of consistency across studies, impeding interstudy comparability. Additionally, some flows such as upstream fugitive emissions have been underestimated. The aforementioned issues have a negative impact on the quality of LCIs. Here, we provide recommendations on how several methods such as equilibrium models, regression, or parameterization can be used to improve data quality, underpinned by more powerful data formats. Open-source models, data platforms, as well as a list of key parameters to be reported are suggested to facilitate reproducibility and enhance transparency of electricity LCIs.
Conclusions
There are several methods and resources that can be used to improve LCIs of electricity supply, enabling more ambitious and powerful analyses. Nonetheless, special care should be taken concerning tradeoffs between different data quality aspects. For instance, more complex and accurate models may result in a loss of transparency and reproducibility unless additional reporting efforts are conducted. Other approaches, such as systematic parameterization do not compromise data quality and should be used to improve the consistency and reproducibility of inventories.
Purpose
Good background data are an important requirement in LCA. Practitioners generally make use of LCI databases for such data, and the ecoinvent database is the largest transparent unit-process LCI database worldwide. Since its first release in 2003, it has been continuously updated, and version 3 was published in 2013. The release of version 3 introduced several significant methodological and technological improvements, besides a large number of new and updated datasets. The aim was to expand the content of the database, set the foundation for a truly global database, support regionalized LCIA, offer multiple system models, allow for easier integration of data from different regions, and reduce maintenance efforts. This article describes the methodological developments.
Methods
Modeling choices and raw data were separated in version 3, which enables the application of different sets of modeling choices, or system models, to the same raw data with little effort. This includes one system model for Consequential LCA. Flow properties were added to all exchanges in the database, giving more information on the inventory and allowing a fast calculation of mass and other balances. With version 3.1, the database is generally water-balanced, and water use and consumption can be determined. Consumption mixes called market datasets were consistently added to the database, and global background data was added, often as an extrapolation from regional data.
Results and discussion
In combination with hundreds of new unit processes from regions outside Europe, these changes lead to an improved modeling of global supply chains, and a more realistic distribution of impacts in regionalized LCIA. The new mixes also facilitate further regionalization due to the availability of background data for all regions.
Conclusions
With version 3, the ecoinvent database substantially expands the goals and scopes of LCA studies it can support. The new system models allow new, different studies to be performed. Global supply chains and market datasets significantly increase the relevance of the database outside of Europe, and regionalized LCA is supported by the data. Datasets are more transparent, include more information, and support, e.g., water balances. The developments also support easier collaboration with other database initiatives, as demonstrated by a first successful collaboration with a data project in Québec. Version 3 has set the foundation for expanding ecoinvent from a mostly regional into a truly global database and offers many new insights beyond the thousands of new and updated datasets it also introduced.
Existing tool for environmental impact assessment of buildings and districts according to the LCA procedure are based upon a static method, considering yearly average processes and impacts. A dynamic method has been developed in order to model the temporal variation of electricity production and allocate environmental impacts to different uses. It allows to evaluate low-energy and plus energy buildings on a more precise basis. Based upon data from the French electricity grid manager, the model evaluates the production mix in terms of temperatures in French climates and several periodic functions corresponding to variation frequencies identified by a Fourier analysis. In a second step, specific production mixes are derived for different uses: heating, cooling, domestic hot water, domestic appliances and office appliances.
Purpose
This discussion article aims to highlight two problematic aspects in the International Reference Life Cycle Data System (ILCD) Handbook: its guidance to the choice between attributional and consequential modeling and to the choice between average and marginal data as input to the life cycle inventory (LCI) analysis.
Methods
We analyze the ILCD guidance by comparing different statements in the handbook with each other and with previous research in this area.
Results and discussion
We find that the ILCD handbook is internally inconsistent when it comes to recommendations on how to choose between attributional and consequential modeling. We also find that the handbook is inconsistent with much of previous research in this matter, and also in the recommendations on how to choose between average and marginal data in the LCI.
Conclusions
Because of the inconsistencies in the ILCD handbook, we recommend that the handbook be revised.
In this study, slinky (the slinky-loop configuration is also known as the coiled loop or spiral loop of flexible plastic pipe)type ground heat exchanger (GHE) was established for a solar-assisted ground source heat pump system. System modelling is performed with the data obtained from the experiment. Artificial neural network (ANN) and adaptive neuro-fuzzy inference system (ANFIS) are used in modelling. The slinky pipes have been laid horizontally and vertically in a ditch. The system coefficient of performance (COPsys) and the heat pump coefficient of performance (COPhp) have been calculated as 2.88 and 3.55, respectively, at horizontal slinky-type GHE, while COPsys and COPhp were calculated as 2.34 and 2.91, respectively, at vertical slinky-type GHE. The obtained results showed that the ANFIS is more successful than that of ANN for forecasting performance of a solar ground source heat pump system.
LCA has evolved from its origins in energy analysis in the 1960s and 70s into a wide ranging tool used to determine impacts of products or systems over several environmental and resource issues. The approach has become more prevalent in research, industry and policy. Its use continues to expand as it seeks to encompass impacts as diverse as resource accounting and social well being. Carbon policy for bioenergy has driven many of these changes.
Enabling assessment of complex issues over a life cycle basis is beneficial, but the process is sometimes difficult. LCA's use in framing is increasingly complex and more uncertain, and in some cases, irreconcilable. The charged environment surrounding biofuels and bioenergy exacerbates all of these. Reaching its full potential to help guide difficult policy discussions and emerging research involves successfully managing LCA's transition from attributional to consequential and from retrospective to prospective.
This paper examines LCA's on-going evolution and its use within bioenergy deployment. The management of methodological growth in the context of the unique challenges associated with bioenergy and biofuels is explored. Changes seen in bioenergy LCA will bleed into other LCA arenas, especially where it is important that a sustainable solution is chosen.
This paper presents a techno-economic analysis of deep energy retrofit strategies aimed at improving a typical existing home to a Net Zero Ready (NZR) level. Three distinct pathways are selected to examine the impact of modifying the mechanical system and building envelope. Each pathway is analyzed in TRNSYS for both the Montreal and Vancouver regions using a validated housing model. A techno-economic analysis methodology then combines the calculated annual energy costs with the associated material and labour costs for each option. Results show that high performance heat pump systems are the preferred option in both cities, highlighting the potential of these technologies in reducing residential energy use in Canada.
This paper presents an analysis of five energy efficient heating and cooling systems for a high performance mid-rise apartment in two Canadian regions: Calgary and Montreal. The analysis was performed using the TRNSYS simulation tool comparing the annual primary and secondary energy consumption, utility costs and greenhouse gas emissions of proposed technologies as well as the 20 year life cycle cost. The five systems selected for comparison include (1) a conventional mid-rise apartment heating and cooling system, (2) boiler/cooling tower water source heat pumps, (3) ground source heat pumps, (4) a cogeneration unit sized to meet the heating load of the building and (5) a cogeneration plus electric driven heat pump system. In Calgary, the cogeneration only system demonstrated the greatest primary energy savings, utility cost savings and greenhouse gas emission reductions of all systems evaluated primarily because of the utility rate structure and electricity generation in the region. The ground source heat pump system demonstrated the greatest secondary energy savings. In Montreal, the ground source heat pump system was predicted to have the greatest savings in all four categories. Evaluating the 20 year life cycle cost of the systems, the base case proved to be the most economical, demonstrating the challenges of implementing energy efficient systems in Canada due to low utility rates.
This report provides the background for the two guidelines “The product, functional unit, and reference flows in LCA” (Weidema et al. 2003a) and “Geographical, technological and temporal delimitation in LCA” (Weidema 2003). It provides further documentation of the examples provided in these guidelines, as well as additional examples, further explanatory text, scientific background and reference to earlier methodological guidelines. It also expands on specific issues, which were not found to be of sufficient general interest to merit inclusion in the guidelines.
This report and the two guidelines that it supports, carry two key messages:
1. The fundamental rule to apply in all methodological choices in life cycle assessment is that the data used must reflect as far as possible the processes actually affected as a consequence of the decision that the specific life cycle assessment is intended to support. Thus, there is a close link between the goal or application area of the life cycle assessment and the methodological choices. This is elaborated in section 1.1.
2. Life cycle assessments, insofar as they deal with comparing potential choices between alternative products, rely heavily on market information, i.e. information on how the market affects the potential choices and how the markets will react to these choices.
Whenever possible, the above understanding has been converted to practical, step-by-step procedures for including market information when:
• defining the functional unit (chapter 3),
• defining the geographical and technological scope (chapter 4),
• handling co-products (chapter 5),
• forecasting data for processes taking place in the future (chapter 6).
For all these elements of the life cycle assessment methodology, the inclusion of market information leads to improvements, which also reduces the uncertainty of life cycle assessment results. While the methodological improvements are described in this report, the consequences for uncertainty are the topic of a separate report: "Reducing uncertainty in LCI. Developing a data collection strategy" (Weidema et al. 2003).
Due to the growing threat of climate change, we are challenged to find improved assessment practises to recognize solutions for sustainable urban development. The focus of the study is on the life cycle design of a district energy system for a new residential development in Finland. This study analyses LCC (life cycle costs) and carbon emissions (LCA (life cycle assessment)), i.e., the “viability” of different energy systems through a methodological life cycle framework. By combining LCC and LCA, a LCM (life cycle management) perspective is portrayed to support decision-making on a long-term basis. The comparable energy design options analysed are (1) district heating (reference design), (2) district heating with building integrated photovoltaic panels, (3) ground source heat pump, and (4) ground source heat pump with building-integrated photovoltaic panels. The results show that the design option with the highest initial investment (4) is in fact the most viable from a life cycle perspective. This study further strengthens the connection between cost savings and carbon emissions reduction in a life cycle context. Thus, by implementing LCC and LCA analysis in an early design phase, justified economic and environmental design decisions can be identified to develop more sustainable urban areas.
Air emissions from shipping have received attention in recent years and the shipping industry is striving for solutions to reduce their emissions and to comply with stricter regulations. Strategies to reduce emissions can consist of a fuel switch, engine changes, or end-of-pipe technologies, but they do not necessarily imply reduced life cycle emissions. The present paper assesses the environmental performance of marine fuels from well-to-propeller using life cycle assessment (LCA). Four fossil fuels are compared: heavy fuel oil (HFO), marine gas oil, gas-to-liquid (GTL) fuel, and liquefied natural gas (LNG), combined with two exhaust abatement techniques: open-loop scrubber and selective catalytic reduction. LNG and other alternatives that comply with the SECA 2015 and Tier III NO(x) requirements give decreased acidification and eutrophication potentials with 78-90 per cent in a life cycle perspective compared with HFO. In contrast, the use of LNG does not decrease the global warming potential by more than 8-20 per cent, the amount depending mainly on the magnitude of the methane slip from the gas engine. None of the fossil fuels scrutinized here would decrease the greenhouse gas emissions significantly from a life cycle perspective. The study supports the need for LCA when evaluating the environmental impact of a fuel change, e.g. it is found that the highest global warming potential during the whole life cycle is connected to the alternatives with GTL fuel.
Purpose
Sustainability assessment in life cycle assessment (LCA) addresses societal aspects of technologies or products to evaluate whether a technology/product helps to address important challenges faced by society or whether it causes problems to society or at least selected social groups. In this paper, we analyse how this has been, and can be addressed in the context of economic assessments. We discuss the need for systemic measures applicable in the macro-economic setting.
Methods
The modelling framework of life cycle costing (LCC) is analysed as a key component of the life cycle sustainability assessment (LCSA) framework. Supply chain analysis is applied to LCC in order to understand the relationships between societal concerns of value adding and the basic cost associated with a functional unit. Methods to link LCC as a foreground economic inventory to a background economy wide inventory such as an input–output table are shown. Other modelling frameworks designed to capture consequential effects in LCSA are discussed.
Results
LCC is a useful indicator in economic assessments, but it fails to capture the full dimension of economic sustainability. It has potential contradictions in system boundary to an environmental LCA, and includes normative judgements at the equivalent of the inventory level. Further, it has an inherent contradiction between user goals (minimisation of cost) and social goals (maximisation of value adding), and has no clear application in a consequential setting. LCC is focussed on the indicator of life cycle cost, to the exclusion of many relevant indicators that can be utilised in LCSA. As such, we propose the coverage of indicators in economic assessment to include the value adding to the economy by type of input, import dependency, indicators associated with the role of capital and labour, the innovation potential, linkages and the structural impact on economic sectors.
Conclusions
If the economic dimension of LCSA is to be equivalently addressed as the other pillars, formalisation of equivalent frameworks must be undertaken. Much can be advanced from other fields that could see LCSA to take a more central role in policy formation.
Background, aim and scopeThis paper discusses the identification of the environmental consequences of marginal electricity supplies in consequential
life cycle assessments (LCA). According to the methodology, environmental characteristics can be examined by identifying affected
activities, i.e. often the marginal technology. The present ‘state-of the-art’ method is to identify the long-term change
in power plant capacity, known as the long-term marginal technology, and assume that the marginal supply will be fully produced
at such capacity. However, the marginal change in capacity will have to operate as an integrated part of the total energy
system. Consequently, it does not necessarily represent the marginal change in electricity supply, which is likely to involve
a mixture of different production technologies. Especially when planning future sustainable energy systems involving combined
heat and power (CHP) and fluctuating renewable energy sources, such issue becomes very important.
Materials and methodsThis paper identifies a business-as-usual (BAU) 2030 projection of the Danish energy system. With a high share of both CHP
and wind power, such system can be regarded a front-runner in the development of future sustainable energy systems in general.
A strict distinction is made between, on the one hand, marginal capacities, i.e. the long-term change in power plant capacities,
and on the other, marginal supply, i.e. the changes in production given the combination of power plants and their individual
marginal production costs. Detailed energy system analysis (ESA) simulation is used to identify the affected technologies,
considering the fact that the marginal technology will change from one hour to another, depending on the size of electricity
demand compared to, among others, wind power and CHP productions. On the basis of such input, a long-term yearly average marginal
(YAM) technology is identified and the environmental impacts are calculated using data from ecoinvent.
ResultsThe results show how the marginal electricity production is not based solely on the marginal change in capacity but can be
characterised as a complex set of affected electricity and heat supply technologies. A long-term YAM technology is identified
for the Danish BAU2030 system in the case of three different long-term marginal changes in capacity, namely coal, natural
gas or wind power.
DiscussionFour analyses and examples of YAMs have been used in order to present examples of the cause–effect chain between a change
in demand for electricity and the installation of new capacity. In order to keep open the possibilities for further analysis
of what can be considered the marginal technology, the results of four different situations are provided. We suggest that
the technology mix with the installation of natural gas or coal power plant is applied as the marginal capacity.
ConclusionsThe environmental consequences of marginal changes in electricity supply cannot always be represented solely by long-term
change in power plant capacity, known as the long-term marginal technology. The marginal change in capacity will have to operate
as an integrated part of the total energy system and, consequently, in most energy systems, one will have to identify the
long-term YAM technology in order to make an accurate evaluation of the environmental consequences.
Recommendations and perspectivesThis paper recommends a combination of LCA and ESA as a methodology for identifying a complex set of marginal technologies.
The paper also establishes values for Danish marginal electricity production as a yearly average (YAM) that can be used in
future LCA studies involving Danish electricity.
KeywordsConsequential LCA-Danish electricity-Energy systems analysis-Marginal electricity-Methodology
PurposeOver the past two decades, consequential life cycle assessment (CLCA) has emerged as a modeling approach for capturing environmental
impacts of product systems beyond physical relationships accounted for in attributional LCA (ALCA). Put simply, CLCA represents
the convergence of LCA and economic modeling approaches.
MethodIn this study, a systematic literature review of CLCA is performed.
ResultsWhile initial efforts to integrate the two modeling methods relied on simple partial equilibrium (PE) modeling and a heuristic
approach to determining affected technologies, more recent techniques incorporate sophisticated economic models for this purpose.
In the last 3years, Multi-Market, Multi-Regional PE Models and Computable General Equilibrium models have been used. Moreover,
the incorporation of other economic notions into CLCA, such as rebound effects and experience curves, has been the focus of
later research. Since economic modeling can play a prominent role in national policy-making and strategic/corporate environmental
planning, developing the capacity to operate LCA concurrent to, or integrated with, these models is of growing importance.
ConclusionsThis paper outlines the historical development of such efforts in CLCA, discusses key methodological advancements, and characterizes
previous literature on the topic. Based on this review, we provide an outlook for further research in CLCA.
KeywordsExperience curves–CLCA–Partial equilibrium modeling–Computable general equilibrium modeling–Consequential life cycle assessment–Rebound effects
This paper reports a techno-economic comparison between a ground-coupled heat pump (GCHP) system and an air-coupled heat pump (ACHP) system. The systems connected to a test room in Firat University, Elazig (38.41°N, 39.14°E), Turkey, were designed and constructed for space cooling. The performances of the GCHP and the ACHP system were experimentally determined. The experimental results were obtained from June to September in cooling season of 2004. The average cooling performance coefficients (COPsys) of the GCHP system for horizontal ground heat exchanger (HGHE) in the different trenches, at 1 and 2 m depths, were obtained to be 3.85 and 4.26, respectively and the COPsys of the ACHP system was determined to be 3.17. The test results indicate that system parameters can have an important effect on performance, and that GCHP systems are economically preferable to ACHP systems for the purpose of space cooling.
In this study, performance experiments and economic analysis of a horizontal ground source heat pump (GSHP) system have been performed. The horizontal GSHP system connected to a test room, Elazığ (38.41°N, 39.14°E), Turkey, was designed and constructed for space heating. The heating and cooling loads of the test room were 2.5 and 3.1 kW at design conditions, respectively. The performance was determined experimentally under real operational conditions. The experimental results were obtained from 7 November 2002 to 3 May 2003 in the heating season of 2002–2003. A detailed cost analysis was presented and payback periods when substituting for different local fuel/power sources were determined. The GSHP system was compared to conventional heating methods (electric resistance, fuel oil, liquid petrol gas, coal, oil and natural gas) in the economical analysis using an annualised life cycle cost method. It was shown that the GSHP system offers economic advantages over the mentioned first five conventional heating methods. However, it is not an economic alternative system to natural gas.
Several states and countries have adopted targets for deep reductions in greenhouse gas emissions by 2050, but there has been
little physically realistic modeling of the energy and economic transformations required. We analyzed the infrastructure and
technology path required to meet California’s goal of an 80% reduction below 1990 levels, using detailed modeling of infrastructure
stocks, resource constraints, and electricity system operability. We found that technically feasible levels of energy efficiency
and decarbonized energy supply alone are not sufficient; widespread electrification of transportation and other sectors is
required. Decarbonized electricity would become the dominant form of energy supply, posing challenges and opportunities for
economic growth and climate policy. This transformation demands technologies that are not yet commercialized, as well as coordination
of investment, technology development, and infrastructure deployment.
The transition to low carbon societies may increase peak electricity demand, which can be costly to supply with renewable energy, whose availability is uncertain. Buildings are often the main cause of peak demand, and they are believed to hold a large unrealised energy-efficiency potential. If realised, this potential could considerably mitigate the transition costs to low carbon societies, reducing average and peak electricity demands.
Space heating and cooling pose fundamental challenges to the achievement of EU decarbonization targets. A comprehensive review of the recent literature acknowledged that district energy systems contribute substantially to the sustainability of energy in the building sector by improving the efficiency and integration of low energy sources. However, a holistic evaluation of the environmental performance of such systems is advisable during the planning and design stage. In this study, we use life cycle assessment to assess the potential contribution and environmental sustainability of renewable heating and cooling alternatives. The unit of analysis is a residential neighbourhood of 1000 inhabitants (equivalent to 250 apartments), located in Tuscany, Italy, served by a district network that provides heating, cooling and sanitary hot water. A geothermal heat pump and a biomass system are compared to two systems based on natural gas as a fossil fuel: a centrally produced heating and cooling system and a more conventional system with single apartment boilers and air–air heat pumps for cooling. The cradle-to-grave analysis shows significant global GHG emission savings of about 35% for the biomass system and about 20% for the GHP system compared with the centralised benchmark system, increasing to 46% and 34%, respectively, with respect to the conventional standalone appliances system. However, other environmental impact categories show different levels of performance depending on the scenario, and in some cases their impact is even greater than that of the benchmarking scenarios. The contributions from each life cycle stage – assembly, operation and end of life – suggest that an eco-design approach could improve the global performances of each scenario. Recommendations for local planning authorities are drawn accordingly.
The European residential building stock is largely composed of buildings with poor energy performance,
therefore basic retrofit actions could lead to significant energy savings. However, energy refurbishment
measures should be identified in accurate way, taking into account the technical viability and aiming both to
increase the building energy performance and to restrain the costs.
The present article investigates the effects of different measures applied to the Italian residential building
stock by using the building typology, which consists of 120 building types, representative of six construction
ages, four building sizes and five climatic zones. A quasi-steady state model has been used to calculate the
energy performance; the economic evaluation has been carried out as specified in the EU cost-optimal
comparative methodology (Directive 2010/31/EU). The most effective measures and packages of measures, in
terms of energy saving and global cost reduction, are identified and discussed.
The results are addressed to important purposes for energy policy, as for instance: (a) to provide political
authorities with the most effective energy efficiency measures as to encourage retrofit processes through the
allocation of financial incentives, (b) to offer a knowledge-base for developing energy refurbishment scenarios of residential building stocks and forecasting future energy resource demand.
The 62nd life cycle assessment (LCA) forum was held on 9 September 2016 to discuss the state of research and application with regard to consequential life cycle assessment. This conference report presents the highlights of the LCA forum. The state of the art of consequential LCA was presented from different viewpoints. It was pointed out that consequential LCA is more than marginal mixes and avoided burdens and involves causal modelling. It was also said that social responsibility calls for consequential LCA. Currently, different models are used to support decision making. It was suggested to make use of the variety of models to check the conclusiveness of their results and thus the reliability of the LCAs. Current and future implementations of consequential LCI models in background databases and linking algorithms were presented. Several speakers presented consequential LCA case studies covering the sectors energy, transport, housing and mining. Some of the LCA models used in the case studies are complemented with general and partial computable equilibrium models and agent-based models and use environmentally extended input-output data or process-based LCA data. Some of the presentations focused on elements such as constrained production, marginal market mixes and technologies or recycling and system expansion. In three parallel workshops, the needs, contents and methodology, and implementation of consequential LCA approaches were discussed. The participants seemed to generally agree on the basic goal that LCA should be able to reflect the consequences of decisions. The inquiry among the participants showed that the demand for consequential LCA studies is hardly existent. The appropriate implementation of consequential modelling in LCA databases and on the appropriate model to be used in consequential LCA case studies was debated. It revealed a need for further and extensive discussions to be able to reach (minimum) consensus.
There has been significant change in the way buildings are constructed and the way building energy performance is evaluated. Focus on solely the use phase of a building is beginning to be replaced by a life-cycle based performance assessment. This study assesses the environmental impact trade-offs between the heat produced to meet a building's space heating load and insulation produced to reduce its space heating load throughout the whole life-cycle of a building. To obtain a more realistic valuation of this tradeoff, a dynamic heat production model, which accounts for political projections regarding change in Danish energy supply was used in the analysis. This novel approach of generating inventory for Life Cycle Assessment (LCA) helped to refine an understanding of optimal insulation levels. The findings of this study discourage the over-insulation of houses connected to the district heating grid, which is being potentially promoted at present in Danish regulation. It is further concluded that improvement of the mineral wool insulation production process could allow for greater levels of environmentally beneficial insulation and would also help in reducing the overall environmental burden from insulating buildings.
Over the past two decades, the integration of environmental concerns into decision making has been gaining prominence both at national and global levels. Sustainable development now factors into policy design as well as industrial technological choices. For this purpose, Life Cycle Assessment (LCA)–which evaluates environmental impacts of products, processes and services through their complete life cycle–is considered a crucial tool to support the integration of environmental sustainability into decision making. In particular, Consequential LCA (CLCA) has emerged as an approach to assess consequences of change, considering both direct and indirect impacts of changes. Currently, no long-term datasets of Consequential Life Cycle Inventories (CLCI) are available, particularly in the case of electricity production mixes. A first and fundamental step to begin filling this gap is to make available data on national level greenhouse gas emissions from electricity and create a typology of electricity production mixes to support policy making. The proposed typology is based on the analysis of the composition of electricity production mixes of 91 countries producing more than 10 TWh in 2012, on the one hand, and of their calculated greenhouse gas (GHG) emissions (in gCO2eq/kWh) from LCA using IPCC 2013 data, on the other hand. All types of primary energy resources are considered, and some are grouped according to similarities in their emissions intensities. Using graphical observations of these two characteristics and a boundary definition, we create a 4-group typology for GHG emissions per kWh, i.e., very low (0–37 gCO2eq/kWh), low (37–300 gCO2eq/kWh), mean (300–600 gCO2eq/kWh) and high ( 600 gCO2eq/kWh). The typology is based on the general characteristics of the electric power generation fleet, corresponding respectively to power systems heavy on hydraulic and/or nuclear power with the remainder of the fleet dominated by renewables; hydraulic and/or nuclear power combined with a diversified mix; gas with a diversified mix; coal, oil and predominantly fossils. This typology describes the general tendencies of the electricity mix and, over time, it can help point to ways in which countries can transition between groups. Further steps should be devoted to the development of indicators taking into account grid interconnection, energy sector resilience in the quest for a mix optimum.
Energy consumption of existing single family homes in cold climate urban centers needs to be reduced. This research presents a process for developing and analyzing retrofit strategies for specific housing archetypes using Toronto (Canada) as a case study. The process was applied to three Toronto urban archetypes with two separate energy intensity goals for heating and cooling: (1) 75 kWh/m2 and (2) Passive House EnerPHit estimated equivalency. Building data was collected through field study and calibrated baseline energy models (EnergyPlus) were created. Retrofit strategies were identified and costs were estimated in consultancy with several experienced Toronto based retrofit contractors. The process utilized a Brute Force method for retrofit selection considering the cost/benefit of each strategy. Furnace and select building envelope parameters were shown to be priorities while windows were not. Energy use reductions of 64-67% and 88-89% from a baseline were achieved when meeting the 75 kWh/m2 and EnerPHit equivalency targets, respectively. The capital costs of 80,000 to achieve the retrofit targets are likely to be prohibitive for homeowners, suggesting that a government funded program is necessary to achieve deep energy retrofits of this nature and to ensure early adoption leading to wide spread market growth.
The development of on-site renewable energy production and demand management in buildings calls for a deeper understanding of the interaction between building operation and the electricity grid. Electricity consumption in buildings varies in terms of seasons (heating and cooling), day of the week (professional activities) and hour of the day, which is also the case of on-site electricity production (e.g. photovoltaic systems). Centralised electricity production varies as well according to the demand (e.g. during peak hours). This research aims at improving the evaluation of potential environmental impacts of an energy efficient house attributable to electricity consumption and production by taking into account the temporal variation of the electricity production. Electricity end-uses and on-site electricity production were evaluated on an hourly basis in the case of an energy-efficient house. Another objective was to investigate the sources of errors in the assessment. Life cycle assessment was used to evaluate potential environmental impacts based on electricity production data for the year 2013 in France. Results were compared using an annual average electricity supply mix versus hourly data. This case study demonstrates that the use of an annual average mix instead of hourly mix data can lead to underestimation of potential impacts up to 39% for Abiotic Depletion Potential (ADP) and 36% for Global warming potential (GWP) when combining all end-uses. Increase of GWP and ADP when using hourly mix data is mainly explained by higher share of coal and gas power plant in the electricity mix in winter. This coincides with a higher electricity consumption of the studied house in this season due to space heating, electric back-up of the solar water heating system and a lower onsite production (photovoltaic system).
Purpose
Existing computational methods for life cycle costing (LCC) are few and appeared inconsistent with the very definition of LCC. This article improves the common matrix-based approach in life cycle assessment as applied to LCC, correcting previous errors.
Methods
Reusing a simple and hypothetical example, the authors derive the LCC from both the physical and monetary technology matrices. Accounting for the added value of all activities in the life cycle leads to a simplified computational structure for LCC.
Results and discussion
The results show that the definition of LCC and computational structure can be fully harmonized with life cycle assessments (LCAs) and simplified. In addition to eco-efficiency calculations, the vector of added values, if disaggregated over social groups, allows for distributional analysis. It is furthermore shown how LCC can account for costs shifting (economic externalities) in the same way as LCA highlights shifting of environmental externalities between different products, life cycle stages or actors.
Conclusions
Life cycle costing as defined by the sum of the added value over the life cycle is consistent with LCA and cradle to gate assessments in particular. The authors simplified the computation of LCC with either the matrix-based approach or the added values of upstream activities as an elementary exchange vector or matrix.
Distributed generation (DG) using renewable energy systems (RES) can play an important role in reducing greenhouse gas (GHG) emissions. Given that DG could overlap with carbon tax implementation, the objective of this work is to assess the implications of introducing different carbon tax levels (from 0 to 100 US/tonne CO 2 eq (60% reduction). Same trend is observed for other environmental impacts, such as resource, human health and ecosystem quality. These results help in giving more insight on how two overlapping clean air policies interfere and how efficient they are in reducing GHG emissions at the same time.
Biomass energy is expected to play a major role in the substitution of renewable energy sources for fossil fuels over the next several decades. The US Energy Information Administration (EIA 2012) forecasts increases in the share of biomass in US energy production from 8 percent in 2009 to 15 percent by 2035. The general view has been that carbon emitted into the atmosphere from biological materials is carbon neutral – part of a closed loop whereby plant regrowth simply recaptures the carbon emissions associated with the energy produced. Recently this view has been challenged, and the US Environmental Protection Agency (EPA) is considering regulations to be applied to biomass energy carbon emissions. A basic approach for analyses of environmental impacts has been the use of life cycle assessment (LCA), a methodology for assessing and measuring the environmental impact of a product over its lifetime – from raw material extraction through materials processing, manufacture, distribution, use, repair and maintenance, and disposal or recycling. However, LCA approaches vary, and the results of alternative methodologies often differ (Helin et al. 2012). This study investigates and compares the implications of these alternative approaches for emissions from wood biomass energy, the carbon footprint, and also highlights the differences in LCA environmental impacts.
A preliminary techno-economic evaluation of retrofitting reciprocating internal combustion engine based cogeneration into existing Canadian houses for the purpose of achieving or approaching net-zero energy rating is presented. Primary energy and electricity consumption, associated greenhouse gas emissions and tolerable capital cost are used as indicators. A whole building simulation model was used to simulate the performance of a commonly used cogeneration system architecture with thermal storage in “typical” single storey houses located in Halifax, Montreal, Toronto, Edmonton and Vancouver, representing the five major climatic regions of Canada. The system is assumed to sell excess electricity to the grid at the purchase price. A high efficiency auxiliary boiler is included to supply heat when cogeneration unit capacity is not sufficient to meet the heating load. The effect of thermal storage capacity, interest rate and acceptable payback period on the overall performance was evaluated through a sensitivity analysis. The findings suggest that internal combustion engine based cogeneration provides a promising option to achieve net-zero energy rating for Canadian houses, and therefore more detailed studies focusing on the entire Canadian housing stock are needed.
In the modern economy, international value chains—production, use, and disposal of goods—have global environmental impacts.
Life Cycle Assessment (LCA) aims to track these impacts and assess them from a systems perspective, identifying strategies
for improvement without burden shifting. We review recent developments in LCA, including existing and emerging applications
aimed at supporting environmentally informed decisions in policy-making, product development and procurement, and consumer
choices. LCA constitutes a viable screening tool that can pinpoint environmental hotspots in complex value chains, but we
also caution that completeness in scope comes at the price of simplifications and uncertainties. Future advances of LCA in
enhancing regional detail and accuracy as well as broadening the assessment to economic and social aspects will make it more
relevant for producers and consumers alike.
http://www.sciencedirect.com/science/article/pii/S0960148114002389
Electricity supply is frequently cited as a significant hot spot in life cycle assessment (LCA) results. Despite its importance, however, LCA research continues to overuse simplified methodologies regarding electricity supply modeling. This work aims to demonstrate the usefulness of electricity trade analysis (proposed model) for integrating the short-term dynamics of electricity supply and refining LCA results. Distributed generation using renewable energy is applied as a case study to demonstrate how electricity trade analysis provides more refined estimates when environmental impact abatements are assessed compared with the conventional (simplified) approaches in LCA. Grid-connected photovoltaic panel (3 kWp mono- and poly-crystalline) and micro-wind turbine (1, 10 and 30 kW) environmental impact abatements are investigated by determining the displaced marginal electricity production on an hourly basis. The results indicate that environmental impact abatements calculated using the developed short-term time horizon approach can be significantly different (up to 200% difference) from those obtained using a simplified approach. Recommendations are provided to LCA practitioners to address this issue of differing results.
Life cycle assessment (LCA) is generally described as a tool for environmental decision making. Results from attributional LCA (ALCA), the most commonly used LCA method, often are presented in a way that suggests that policy decisions based on these results will yield the quantitative benefits estimated by ALCA. For example, ALCAs of biofuels are routinely used to suggest that the implementation of one alternative (say, a biofuel) will cause an X% change in greenhouse gas emissions, compared with a baseline (typically gasoline). However, because of several simplifications inherent in ALCA, the method, in fact, is not predictive of real-world impacts on climate change, and hence the usual quantitative interpretation of ALCA results is not valid. A conceptually superior approach, consequential LCA (CLCA), avoids many of the limitations of ALCA, but because it is meant to model actual changes in the real world, CLCA results are scenario dependent and uncertain. These limitations mean that even the best practical CLCAs cannot produce definitive quantitative estimates of actual environmental outcomes. Both forms of LCA, however, can yield valuable insights about potential environmental effects, and CLCA can support robust decision making. By openly recognizing the limitations and understanding the appropriate uses of LCA as discussed here, practitioners and researchers can help policy makers implement policies that are less likely to have perverse effects and more likely to lead to effective environmental policies, including climate mitigation strategies.
In 1998 the Canadian government introduced the EnerGuide for Houses (EGH) program, essentially consisting of home energy audits with financial incentives provided to the homeowner upon verification that sufficient auditor-recommended upgrades were undertaken to achieve energy savings. In this study, we analyze the EGH data compiled between October 1998 and September 2005 to determine what types of households chose to participate and what appear to be the main factors underlying retrofit decisions. In the program, homeowners were prescribed specific upgrade types in the first audit. Hence, the decision problem involves whether to retrofit at all and how many of the prescribed upgrades to adopt. Moreover, the second audit that reveals this decision does not reflect the possibility that some homeowners might have undertaken the recommended upgrades but opted not to or have yet to undergo the second audit. We adopt an econometric technique that takes these features of the data into account. We find that energy cost savings, financial incentives, and costs of retrofits are important factors behind retrofit decisions given several other home- and household-specific characteristics.
The development of a simulation tool that can accurately characterize the energy performance of the Canadian housing stock would enable detailed studies to predict the impact of energy saving upgrades and technologies on a national scale. Such a tool requires a detailed database of house descriptions that collectively represent the entire housing stock. Such a database has been assembled by selectively extracting measured and observed data collected by professionals who conducted on-site audits of 200,000 houses. The auditors' data were extracted to statistically match key parameters (location, house type, vintage, geometry and heating system) with a broad-based random survey of the Canadian stock. The result is a database comprised of nearly 17,000 detailed records of single-detached, double and row houses. Each of these house records represents 500 houses in the Canadian stock and contains sufficient data to enable the accurate characterization of its energy performance through building performance simulation.
Carbon dioxide (CO2) emissions from biomass combustion are traditionally assumed climate neutral if the bioenergy system is carbon (C) flux neutral, i.e. the CO2 released from biofuel combustion approximately equals the amount of CO2 sequestered in biomass. This convention, widely adopted in life cycle assessment (LCA) studies of bioenergy systems, underestimates the climate impact of bioenergy. Besides CO2 emissions from permanent C losses, CO2 emissions from C flux neutral systems (that is from temporary C losses) also contribute to climate change: before being captured by biomass regrowth, CO2 molecules spend time in the atmosphere and contribute to global warming. In this paper, a method to estimate the climate impact of CO2 emissions from biomass combustion is proposed. Our method uses CO2 impulse response functions (IRF) from C cycle models in the elaboration of atmospheric decay functions for biomass-derived CO2 emissions. Their contributions to global warming are then quantified with a unit-based index, the GWPbio. Since this index is expressed as a function of the rotation period of the biomass, our results can be applied to CO2 emissions from combustion of all the different biomass species, from annual row crops to slower growing boreal forest.
Renewable distributed electricity generation can play a significant role in meeting today's energy policy goals, such as reducing greenhouse gas emissions, improving energy security, while adding supply to meet increasing energy demand. However, the exact potential benefits are still a matter of debate. The objective of this study is to evaluate the life cycle implications (environmental, economic and energy) of distributed generation (DG) technologies. A complementary objective is to compare the life cycle implications of DG technologies with the centralized electricity production representing the Northeastern American context. Environmental and energy implications are modeled according to the recommendations in the ISO 14040 standard and this, using different indicators: Human Health; Ecosystem Quality; Climate Change; Resources and Non-Renewable Energy Payback Ratio. Distinctly, economic implications are modeled using conventional life cycle costing. DG technologies include two types of grid-connected photovoltaic panels (3Â kWp mono-crystalline and poly-crystalline) and three types of micro-wind turbines (1, 10 and 30Â kW) modeled for average, below average and above average climatic conditions in the province of Quebec (Canada). A sensitivity analysis was also performed using different scenarios of centralized energy systems based on average and marginal (short- and long-term) technology approaches. Results show the following. First, climatic conditions (i.e., geographic location) have a significant effect on the results for the environmental, economic and energy indicators. More specifically, it was shown that the 30Â kW micro-wind turbine is the best technology for above average conditions, while 3Â kWp poly-crystalline photovoltaic panels are preferable for below average conditions. Second, the assessed DG technologies do not show benefits in comparison to the centralized Quebec grid mix (average technology approach). On the other hand, the 30Â kW micro-wind turbine shows a potential benefit as long as the Northeastern American electricity market is considered (i.e., oil and coal centralized technologies are affected for the short- and long-term marginal scenarios, respectively). Photovoltaic panels could also become more competitive if the acquisition cost decreased. In conclusion, DG utilization will represent an improvement over centralized electricity production in a Northeastern American context, with respect to the environmental, energy and economic indicators assessed, and under the appropriate conditions discussed (i.e., geographical locations and affected centralized electricity production scenarios).
PurposeThere has been an increased interest in utilizing renewable energy sources in district heating systems. District heating systems
are centralized systems that provide heat for residential and commercial buildings in a community. While various renewable
and conventional energy sources can be used in such systems, many stakeholders are interested in choosing the feasible option
with the least environmental impacts. This paper evaluates and compares environmental burdens of alternative energy source
options for the base–load of a district heating center in Vancouver, British Columbia (BC) using the life cycle assessment
method. The considered energy sources include natural gas, wood pellet, sewer heat, and ground heat.
MethodsThe life cycle stages considered in the LCA model cover all stages from fuel production, fuel transmission/transportation,
construction, operation, and finally demolition of the district heating system. The impact categories were analyzed based
on the IMPACT 2002+ method.
Results and discussionOn a life-cycle basis, the global warming effect of renewable energy options were at least 200kgeqCO2 less than that of the
natural gas option per MWh of heat produced by the base–load system. It was concluded that less than 25% of the upstream global
warming impact associated with the wood pellet energy source option was due to transportation activities and about 50% of
that was resulted from wood pellet production processes. In comparison with other energy options, the wood pellets option
has higher impacts on respiratory of inorganics, terrestrial ecotoxicity, acidification, and nutrification categories. Among
renewable options, the global warming impact of heat pump options in the studied case in Vancouver, BC, were lower than the
wood pellet option due to BC's low carbon electricity generation profile. Ozone layer depletion and mineral extraction were
the highest for the heat pump options due to extensive construction required for these options.
ConclusionsNatural gas utilization as the primary heat source for district heat production implies environmental complications beyond
just the global warming impacts. Diffusing renewable energy sources for generating the base–load district heat would reduce
human toxicity, ecosystem quality degradation, global warming, and resource depletion compared to the case of natural gas.
Reducing fossil fuel dependency in various stages of wood pellet production can remarkably reduce the upstream global warming
impact of using wood pellets for district heat generation.
KeywordsDistrict heating systems–Environmental impacts–Global warming–Life cycle assessment–Renewable energy–Wood pellets
The "Impact Assessment" of Life Cycle Assessment is a broad topic which is currently being discussed controversally. In the past, impact assessment methods were developed in order to help to derive information from the inventory and in order to attain informed decision making. Due to the fact that volume and content of the Life Cycle Inventories has grown significantly with time, it has become more and more difficult to draw conclusions directly. Thus, impact assessment was invented. Different methodologies were published and SETAC founded working groups on this item in both North America and Europe. Today, "Impact Assessment" is a research topic. With time, people have begun to understand that the impact assessment idea covers more than only the concentration of information coming from the inventory. The more people who have started working with impact assessment, the more the added value of this methodology has come to the surface. Today it is broadly accepted that impact assessment is the only interface of LCA with the environment. Dealing with the potential effects and impacts of the interventions identified in the inventory, impact assessment offers a great opportunity to enlarge the conclusions which can be drawn from the whole LCA and offers a truly iterative nature by setting requirements and providing help as to which data has to be collected due to the respective relevance to the environment.
Before new technologies enter the market, their environmental superiority over competing options must be asserted based on a life cycle approach. However, when applying the prevailing status-quo Life Cycle Assessment (LCA) approach to future renewable energy systems, one does not distinguish between impacts which are ‘imported’ into the system due to the ‘background system’ (e.g. due to supply of materials or final energy for the production of the energy system), and what is the improvement potential of these technologies compared to competitors (e.g. due to process and system innovations or diffusion effects). This paper investigates a dynamic approach towards the LCA of renewable energy technologies and proves that for all renewable energy chains, the inputs of finite energy resources and emissions of greenhouse gases are extremely low compared with the conventional system. With regard to the other environmental impacts the findings do not reveal any clear verdict for or against renewable energies.Future development will enable a further reduction of environmental impacts of renewable energy systems. Different factors are responsible for this development, such as progress with respect to technical parameters of energy converters, in particular, improved efficiency; emissions characteristics; increased lifetime, etc.; advances with regard to the production process of energy converters and fuels; and advances with regard to ‘external’ services originating from conventional energy and transport systems, for instance, improved electricity or process heat supply for system production and ecologically optimized transport systems for fuel transportation.The application of renewable energy sources might modify not only the background system, but also further downstream aspects, such as consumer behavior. This effect is, however, strongly context and technology dependent.
Taking advantage of offshore wind power appears to be of special significance for the climate protection plans announced by the German Federal Government. For this reason, a comprehensive system analysis of the possible CO2 reduction including the consideration of all relevant processes has to be performed. This goal can be achieved by linking a life-cycle assessment model of offshore wind utilisation with a stochastic model of the German electricity market. Such an extended life-cycle assessment shows that the CO2 emissions from the construction and operation of wind farms are low compared with the substitution effects of fossil fuels. Additionally, in the German electricity system, offshore wind energy is the main substitute for medium-load power plants. CO2 emissions from the modified operation and the expansion of conventional power plants reduce the CO2 savings, but the substitution effect outweighs these emissions by one order of magnitude. The assumptions of the model, shown here to be above all CO2 certificate prices, have a considerable influence on the figures shown due to a significant effect on the future energy mix.
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