Beyond Operational Energy Efficiency: A Balanced Sustainability Index from a Life Cycle Consideration

Most deep energy renovation projects focus only on an operating energy reduction and disregard the added embodied energy derived from adding insulation, window/door replacement, and mechanical system replacement or upgrades. It is important to study and address the balance and trade-offs between reduced operating energy and added embodied energy from a whole life cycle perspective to reduce the overall building carbon footprint. However, the added embodied energy and related environmental impact have not been studied extensively. In response to this need, this paper proposes a holistic sustainability index that balances the trade-off between reduced operating energy and added embodied energy. Eight case projects are used to validate the proposed method and calculation. The findings demonstrate that using a balanced sustainability index can reveal results different from a conventional operating energy-centric approach: (a) operating energy savings can be offset by the embodied energy gain, (b) the operating energy savings do not always result in a life cycle emissions reduction, and (c) the sustainability index can vary depending on the priorities the decision makers give to operating carbon, embodied carbon, and operating cost. Overall, the proposed sustainability score can provide us with a more comprehensive understanding of how sustainable the renovation works are from a life cycle carbon emissions perspective, providing a more robust estimation of global warming potential related to building renovation.

Download Full-text

Strategies to Improve the Energy Performance of Buildings: A Review of Their Life Cycle Impact

Buildings ◽

10.3390/buildings8080105 ◽

2018 ◽

Vol 8 (8) ◽

pp. 105 ◽

Cited By ~ 14

Author(s):

Nadia MIRABELLA ◽

Martin RÖCK ◽

Marcella Ruschi Mendes SAADE ◽

Carolin SPIRINCKX ◽

Marc BOSMANS ◽

...

Keyword(s):

Life Cycle ◽

Case Studies ◽

Environmental Impacts ◽

Energy Use ◽

Ghg Emissions ◽

Energy Performance ◽

Environmental Benefits ◽

Embodied Energy ◽

Trade Offs ◽

Operational Energy

Globally, the building sector is responsible for more than 40% of energy use and it contributes approximately 30% of the global Greenhouse Gas (GHG) emissions. This high contribution stimulates research and policies to reduce the operational energy use and related GHG emissions of buildings. However, the environmental impacts of buildings can extend wide beyond the operational phase, and the portion of impacts related to the embodied energy of the building becomes relatively more important in low energy buildings. Therefore, the goal of the research is gaining insights into the environmental impacts of various building strategies for energy efficiency requirements compared to the life cycle environmental impacts of the whole building. The goal is to detect and investigate existing trade-offs in current approaches and solutions proposed by the research community. A literature review is driven by six fundamental and specific research questions (RQs), and performed based on two main tasks: (i) selection of literature studies, and (ii) critical analysis of the selected studies in line with the RQs. A final sample of 59 papers and 178 case studies has been collected, and key criteria are systematically analysed in a matrix. The study reveals that the high heterogeneity of the case studies makes it difficult to compare these in a straightforward way, but it allows to provide an overview of current methodological challenges and research gaps. Furthermore, the most complete studies provide valuable insights in the environmental benefits of the identified energy performance strategies over the building life cycle, but also shows the risk of burden shifting if only operational energy use is focused on, or when a limited number of environmental impact categories are assessed.

Download Full-text

The importance of embodied energy in carbon footprint assessment

Structural Survey ◽

10.1108/ss-01-2013-0012 ◽

2014 ◽

Vol 32 (1) ◽

pp. 49-60 ◽

Cited By ~ 31

Author(s):

Zaid Alwan ◽

Paul Jones

Keyword(s):

Life Cycle ◽

Carbon Footprint ◽

Embodied Energy ◽

Total Carbon ◽

Design Team ◽

Content Type ◽

Operational Energy ◽

The Impact ◽

Whole Life Cycle

Purpose – The construction industry has focused on operational and embodied energy of buildings as a way of becoming more sustainable, however, with more emphasis on the former. The purpose of this paper is to highlight the impact that embodied energy of construction materials can have on the decision making when designing buildings, and ultimately on the environment. This is an important aspect that has often been overlooked when calculating a building's carbon footprint; and its inclusion this approach presents a more holistic life cycle assessment. Design/methodology/approach – A building project was chosen that is currently being designed; the design team for the project have been tasked by the client to make the facility exemplary in terms of its sustainability. This building has a limited construction palette; therefore the embodied energy component can be accurately calculated. The authors of this paper are also part of the design team for the building so they have full access to Building Information Modelling (BIM) models and production information. An inventory of materials was obtained for the building and embodied energy coefficients applied to assess the key building components. The total operational energy was identified using benchmarking to produce a carbon footprint for the facility. Findings – The results indicate that while operational energy is more significant over the long term, the embodied energy of key materials should not be ignored, and is likely to be a bigger proportion of the total carbon in a low carbon building. The components with high embodied energy have also been identified. The design team have responded to this by altering the design to significantly reduce the embodied energy within these key components – and thus make the building far more sustainable in this regard. Research limitations/implications – It may be is a challenge to create components inventories for whole buildings or for refurbishments. However, a potential future approach for is application may be to use a BIM model to simplify this process by imbedding embodied energy inventories within the software, as part of the BIM menus. Originality/value – This case study identifies the importance of considering carbon use during the whole-life cycle of buildings, as well as highlighting the use of carbon offsetting. The paper presents an original approach to the research by using a “live” building as a case study with a focus on the embodied energy of each component of the scheme. The operational energy is also being calculated, the combined data are currently informing the design approach for the building. As part of the analysis, the building was modelled in BIM software.

Download Full-text

Energy performance of an exhibition hall in a life cycle perspective: embodied energy, operational energy and retrofit strategies

Energy Efficiency ◽

10.1007/s12053-017-9521-8 ◽

2017 ◽

Vol 10 (6) ◽

pp. 1343-1364 ◽

Cited By ~ 6

Author(s):

Giancarlo Paganin ◽

Adriana Angelotti ◽

Chiara Ducoli ◽

Monica Lavagna ◽

Cinzia Talamo ◽

...

Keyword(s):

Life Cycle ◽

Energy Performance ◽

Embodied Energy ◽

Exhibition Hall ◽

Life Cycle Perspective ◽

Operational Energy

Download Full-text

The Life-Cycle Energy Consumption Distribution of Buildings in China

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1008-1009.1320 ◽

2014 ◽

Vol 1008-1009 ◽

pp. 1320-1325

Author(s):

Zhao Dong Li ◽

Yu Rong Yao ◽

Geng Dai ◽

Yi Chu Ding

Keyword(s):

Life Cycle ◽

Energy Consumption ◽

Energy Distribution ◽

Building Materials ◽

Policy Formulation ◽

Embodied Energy ◽

Practical Significance ◽

Operational Energy ◽

Materials Recycling ◽

Material Energy

In recent years, continues development of China urbanization gradually increases the energy consumption of buildings. Studies on the life cycle energy distribution of buildings have practical significance to determine energy policy formulation and adjustment. Based on previous studies and the composition of the life cycle energy consumption of buildings, this article constructed a life-cycle energy consumption model, and established the calculation methods of initial embodied energy, operational energy, reset embodied energy ,dismantle embodied energy and recycle embodied energy separately. Based on ICE material energy data and combined rating per machine per team, this article calculated the life cycle energy distribution of a building in Nanjing. We found that the life cycle energy of buildings obeyed normal distribution, the operational energy accounts for a large proportion and it decreases with the decreased life cycle of buildings. The recovery of operational energy can reduce the proportion of the initial embodied energy. Considering the studies, in order to meet the characteristic of the buildings in China which have short life cycle, we should focus on the development of building materials recycling and reusing.

Download Full-text

Environmental Performance Measures to Assess Building Refurbishment from a Life Cycle Perspective

Energies ◽

10.3390/en12020299 ◽

2019 ◽

Vol 12 (2) ◽

pp. 299 ◽

Cited By ~ 4

Author(s):

Helena Nydahl ◽

Staffan Andersson ◽

Anders Åstrand ◽

Thomas Olofsson

Keyword(s):

Life Cycle Assessment ◽

Life Cycle ◽

Environmental Performance ◽

Ghg Emissions ◽

Assessment Method ◽

The European Union ◽

Building Stock ◽

Life Cycle Perspective ◽

Building Refurbishment ◽

Operational Energy

Energy efficiency investments in existing buildings are an effective way of reducing the environmental impact of the building stock. Even though policies in the European Union and elsewhere promote a unilateral focus on operational energy reduction, scientific studies highlight the importance of applying a life cycle perspective to energy refurbishment. However, life cycle assessment is often perceived as being complicated and the results difficult to interpret by the construction sector. There is also a lack of guidelines regarding the sustainable ratio between the embodied and accumulated operational impact. The scope of this study is to introduce a life cycle assessment method for building refurbishment that utilizes familiar economic performance tools, namely return on investment and annual yield. The aim is to use the introduced method to analyze a case building with a sustainability profile. The building was refurbished in order to reduce its operational energy use. The introduced method is compatible with a theory of minimum sustainable environmental performance that may be developed through backcasting from defined energy and GHG emissions objectives. The proposed approach will hopefully allow development of sustainable refurbishment objectives that can support the choice of refurbishment investments.

Download Full-text

Life Cycle Energy and CO2 Emissions of Residential Buildings in Bandung, Indonesia

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.689.54 ◽

2013 ◽

Vol 689 ◽

pp. 54-59 ◽

Cited By ~ 3

Author(s):

Usep Surahman ◽

Tetsu Kubota

Keyword(s):

Life Cycle ◽

Energy Consumption ◽

Co2 Emissions ◽

Residential Buildings ◽

Embodied Energy ◽

Data Availability ◽

Assessment Model ◽

Output Analysis ◽

Simple Medium ◽

Operational Energy

This study aims to develop a simplified life cycle assessment model for residential buildings in Indonesia, which can be used under relatively poor data availability conditions. In order to obtain material inventory data and household energy consumption profiles for constructing the above model, a survey was conducted in Bandung in 2011. This paper analyzes life cycle energy and CO2 emissions employing an input-output analysis-based method within unplanned houses (n=250), which are classified into three categories, namely simple, medium and luxurious houses. The results showed that the average embodied energy of simple, medium and luxurious houses was 36.3, 130.0 and 367.7 GJ respectively. The cement consumed the largest energy and emitted the most CO2 emissions among all materials. The annual average operational energy of simple, medium and luxurious houses varied widely at 11.6, 17.4 and 32.1 GJ/year respectively. The energy consumption for cooking accounted for the largest percentage of operational energy. The profiles of life cycle CO2 emissions were similar with those of life cycle energy. The factors affecting embodied, operational and life cycle energy were also studied.

Download Full-text

Income Dynamics and the Life Cycle

Journal of Social Policy ◽

10.1017/s0047279406009858 ◽

2006 ◽

Vol 35 (3) ◽

pp. 411-435 ◽

Cited By ~ 20

Author(s):

JOHN RIGG ◽

TOM SEFTON

Keyword(s):

Life Cycle ◽

Life Events ◽

Financial Impact ◽

Panel Survey ◽

Income Dynamics ◽

Poverty Dynamics ◽

Partnership Formation ◽

Life Cycle Perspective ◽

Whole Life Cycle ◽

The Welfare State

This article argues that our understanding of income and poverty dynamics benefits from taking a life-cycle perspective. A person's age and family circumstances – the factors that shape their life cycle – affect the likelihood of experiencing key life events, such as partnership formation, having children, or retirement; this in turn affects their probability of experiencing rising, falling, or other income trajectories. Using ten waves of the British Household Panel Survey, we analyse the income trajectories of people at different stages in their lives in order to build a picture of income dynamics over the whole life cycle. We find that particular life events are closely associated with either rising or falling trajectories, but that there is considerable heterogeneity in income trajectories following these different events. Typically, individuals experiencing one of these life events are around twice as likely to experience a particular income trajectory, but most individuals will not follow the trajectory most commonly associated with that life event. This work improves our understanding of the financial impact of different life events and provides an indication of how effectively the welfare state cushions people against the potentially adverse impact of these events.

Download Full-text

On the Retrofit of Existing Buildings with Aerogel Panels: Energy, Environmental and Economic issues

Energies ◽

10.3390/en14051276 ◽

2021 ◽

Vol 14 (5) ◽

pp. 1276

Author(s):

Paola Marrone ◽

Francesco Asdrubali ◽

Daniela Venanzi ◽

Federico Orsini ◽

Luca Evangelisti ◽

...

Keyword(s):

Life Cycle ◽

Energy Demand ◽

Net Present Value ◽

Energy Savings ◽

Cost Benefit Analysis ◽

Cost Benefit ◽

Tax Incentive ◽

Lump Sum ◽

Assessment Approach ◽

Whole Life Cycle

Among the super insulating materials, aerogel has interesting properties: very low thermal conductivity and density, resistance to high temperatures and transparency. It is a rather expensive material, but incentives in the field can improve its economic attractiveness. Starting from this, the thermal behavior of a test building entirely insulated with aerogel panels was investigated through an extended experimental campaign. A dynamic simulation model of a case study building was generated to better comprehend the energy savings obtained through aerogel in terms of energy demand over a whole year. The investigation was completed by computing the carbon and energy payback times of various retrofit strategies through a life cycle assessment approach, as well as by a cost-benefit analysis through a probabilistic financial framework. Compared to conventional insulation materials, aerogel is characterized by a higher energy and carbon payback time, but it guarantees better environmental performance in the whole life cycle. From an economic-financial perspective, the aerogel retrofit is the best in the current tax incentive scenario. However, due to its higher lump-sum investment, aerogel’s net present value is very sensitive to tax deductions, and it is riskier than the best comparable materials in less favorable tax scenarios.

Download Full-text

Life cycle energy analysis of a green building in Vietnam

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1212/1/012004 ◽

2022 ◽

Vol 1212 (1) ◽

pp. 012004

Author(s):

D L Le ◽

T Q Nguyen ◽

H C Pham

Keyword(s):

Life Cycle ◽

Energy Analysis ◽

Green Building ◽

Green Buildings ◽

Convincing Evidence ◽

Simulation Software ◽

Embodied Energy ◽

Operational Energy ◽

Life Cycle Energy Analysis

Abstract The paper presents the life cycle energy analysis (LCEA) of an office green building in Hanoi, Vietnam to prove the advantages of green buildings regarding energy efficiency and environmental effects. The case study building is a concrete structured one, which consists of 3 basements, 17 floors, and 1 attic with a gross area of 14,112 m2. In the study, the building’s embodied energy is determined based on the contained energy coefficient of the ith material and its quantity needed. Whereas, the operating energy is computed according to the annual energy consumption of the building, which is stimulated by the EnergyPlus simulation software. Relying on the relative share of the demolition energy with the life cycle energy that has been proposed by previous publications, this category will be estimated. Results showed that the initial embodied energy contributed the largest share to the life cycle energy (61.37%), followed by operational energy (27.61%). It also indicated that the percentage share of the operational energy of a green building is much lower than that of other buildings. The primary reason for this is associated with the usage of environmentally friendly materials and energy-saving equipment in the design option of the green building. Therefore, it can be convincing evidence that may help to change the mindset of decision-makers in Vietnam about green buildings.

Download Full-text

A LIFE CYCLE ENERGY COMPARISON OF THREE WORLD EXPO BUILDINGS

Journal of Green Building ◽

10.3992/jgb.6.3.151 ◽

2011 ◽

Vol 6 (3) ◽

pp. 151-167 ◽

Cited By ~ 1

Author(s):

Shanshan Shen ◽

Brenda Vale ◽

Robert Vale

Keyword(s):

Energy Efficiency ◽

Life Cycle ◽

Energy Demand ◽

Energy Use ◽

Embodied Energy ◽

Environmental Damage ◽

Building Performance ◽

Energy Flows ◽

World Expo ◽

Whole Life Cycle

Over the last hundred years the booming exhibition industry has promoted development, which in turn has led to environmental damage. The construction of exhibition buildings has been part of this phenomenon. At first sight improvement in energy efficiency techniques would seem to offset the increased energy demand from both exhibitions and exhibition buildings. However, whether energy efficiency technologies truly help to improve building performance to the point where a building is ‘environmentally friendly’ throughout its whole life-cycle is uncertain. This research is part of investigating whether energy efficiency technologies are really the easiest means to lower costs and energy requirements when the whole useful life of an exhibition building is considered. This article investigates the energy use of three case study buildings based on their operating and embodied energy flows. The results suggest that modern technologies for making exhibition buildings more sustainable may not be as effective as the simpler strategies used over 100 years ago. This suggests a different approach may be needed for sustainable development in the twenty first century.

Download Full-text