Life cycle cost analysis of energy efficiency design options for refrigerators in Brazil

The purpose of this paper was to present the results of a life cycle cost analysis concerning the purchase and operation of a more efficient popular refrigerator model compared with a baseline design in Brazil. The summarized results may be useful for organizations working to promote sustainable energy development. This paper specifically focuses on refrigerators, since their energy consumption is predicted to constitute over 30% of the total average domestic electricity bill in Brazilian households. If all new Brazilian refrigerators had an energy efficiency at the level consistent with the least life cycle cost of ownership, it would result in an annual savings of 2.8 billion dollars (US$) in electricity bills, 45 TWh of electricity demand, and 18 Mt of CO₂ emissions, with a respective payback period of 7 years which is less than half the average estimated lifetime of a refrigerator. The analysis was conducted following the guidelines of similar analyses available from the US Department of Energy and the Collaborative Labeling and Appliance Standards Program.

Life cycle analysis of energy use and greenhouse gas emissions for road transportation fuels in China

Life cycle analysis is considered to be a valuable tool for decision making towards sustainability. Life cycle energy and environmental impact analysis for conventional transportation fuels and alternatives such as biofuels has become an active domain of research in recent years. The present study attempts to identify the most reliable results to date and possible ranges of life cycle fossil fuel use, petroleum use and greenhouse gas emissions for various road transportation fuels in China through a comprehensive review of recently published life cycle studies and review articles. Fuels reviewed include conventional gasoline, conventional diesel, liquefied petroleum gas, compressed natural gas, wheat-derived ethanol, corn-derived ethanol, cassava-derived ethanol, sugarcane-derived ethanol, rapeseed-derived biodiesel and soybean-derived biodiesel. Recommendations for future work are also discussed.     

Life cycle energy analysis of a residential building with different envelopes and climates in Indian context

In this paper life cycle energy (LCE) demand of a residential building of usable floor area about 85.5 m² located at Hyderabad (Andhra Pradesh), India is evaluated under different envelopes and climates in Indian context. The house is studied with conventional (fired clay) and alternative wall materials (hollow concrete, soil cement, fly ash and aerated concrete) under varying thickness of wall, and insulation (expanded polystyrene) on wall and roof. The house is modelled for five different climatic zones of India, i.e. hot and dry, warm and humid, composite, cold and moderate. Study suggests that alternative wall materials alone (without insulation) reduce LCE demand of the building by 1.5-5%. Aerated concrete (AC), as wall material, has better energy performance over other materials. LCE savings are significant when insulation is added to external wall and roof. It varies from 10% to 30% depending on the climatic conditions. Maximum LCE savings with insulation are observed for warm and humid climate and least for moderate climate. For same thickness of insulation, LCE savings are much more with roof insulation than wall insulation. But wall insulation is found to be preferable to a thicker wall. It is also observed that there is a limit for thickness of insulation that can be applied on external walls and roof from life cycle point of view. This limit is found to be about 10 cm for composite, hot and dry, warm and humid, and cold climates and 5 cm for moderate climate.     

Factors influencing energy efficiency investments in existing Swedish residential buildings

We used the data from a survey conducted in 2008 of 3,000 owners of detached houses to analyse the factors that influence the adoption of investment measures to improve the energy efficiency of their buildings. For the majority of Swedish homeowners, it was important to reduce their household energy use, and most of them undertook no-cost measures as compared to investment measures. Personal attributes such as income, education, age and contextual factors, including age of the house, thermal discomfort, past investment, and perceived energy cost, influence homeowners’ preference for a particular type of energy efficiency measure. The implications for promoting the implementation of energy efficiency investment measures are discussed.     

Life cycle assessment of a solar thermal collector: sensitivity analysis, energy and environmental balances

Starting from the results of a life cycle assessment of solar thermal collector for sanitary warm water, an energy balance between the employed energy during the collector life cycle and the energy saved thanks to the collector use has been investigated. A sensitivity analysis for estimating the effects of the chosen methods and data on the outcome of the study was carried out. Uncertainties due to the eco-profile of input materials and the initial assumptions have been analysed.Since the study is concerned with a renewable energy system, attention has been focused on the energy indexes and in particular the “global energy consumption”. Following the principles of Kyoto Protocol, the variations of CO₂ emissions have also been studied.     

Development of a new energy efficiency rating system for existing residential buildings

Building energy efficiency rating systems have been established worldwide to systematically manage the energy consumption of existing buildings. This study aimed to develop a new energy efficiency rating system for existing residential buildings from two perspectives: (i) establishment of reasonable and fair criteria for the building energy efficiency rating system; and (ii) establishment of comparative incentive and penalty programs to encourage the voluntary participation of all residents in the energy saving campaign. Based on the analysis of the conventional energy efficiency rating system for existing residential buildings, this study was conducted in five steps: (i) data collection and analysis; (ii) correlation analysis between the household size and the CO₂ emission density (i.e., CO₂ emission per unit area); (iii) cluster formation based on results of the correlation analysis using a decision tree; (iv) establishment of a new energy efficiency rating system for existing buildings; and (v) establishment of incentive and penalty programs using advanced case-based reasoning. The proposed system can allow a policymaker to establish a reasonable and fair energy efficiency rating system for existing residential buildings and can encourage the voluntary participation of all residents in the energy saving campaign.     

Life cycle energy and greenhouse emissions analysis of wind turbines and the effect of size on energy yield

Wind turbines, used to generate renewable energy, are typically considered to take only a number of months to produce as much energy as is required in their manufacture and operation. With a life expectancy of upwards of 20 years, the energy produced by wind turbines over their life can be many times greater than that embodied in their production. Many previous life cycle energy studies of wind turbines are based on methods of assessment now known to be incomplete. These studies may underestimate the energy embodied in wind turbines by more than 50%, potentially overestimating the energy yield of those systems and possibly affecting the comparison of energy generation options. With the increasing trend towards larger scale wind turbines, comes a respective increase in the energy required for their manufacture. It is important to consider whether or not these increases in wind turbine size, and thus embodied energy, can be adequately justified by equivalent increases in the energy yield of such systems. This paper presents the results of a life cycle energy and greenhouse emissions analysis of two wind turbines and considers the effect of wind turbine size on energy yield. The issue of incompleteness associated with many past life cycle energy studies is also addressed. Energy yield ratios of 21 and 23 were found for a small and large scale wind turbine, respectively. The embodied energy component was found to be more significant than in previous studies, emphasised here due to the innovative use of a hybrid embodied energy analysis approach. The life cycle energy requirements were shown to be offset by the energy produced within the first 12 months of operation. The size of wind turbines appears to not be an important factor in optimising their life cycle energy performance.     

Life cycle assessment of high temperature electrolysis for hydrogen production via nuclear energy

A life cycle assessment (LCA) of one proposed method of hydrogen production—the high temperature electrolysis of water vapor—is presented in this paper. High temperature electrolysis offers an advantage of higher energy efficiency over the conventional low-temperature alkaline electrolysis due to reduced cell potential and consequent electrical energy requirements. The primary energy source for the electrolysis will be advanced nuclear reactors operating at temperatures corresponding to those required for the high temperature electrolysis. The LCA examines the environmental impact of the combined advanced nuclear-high temperature electrolysis plant, focusing upon quantifying the emissions of carbon dioxide, sulfur dioxide, and nitrogen oxides per kilogram of hydrogen produced. The results are presented in terms of the global warming potential (GWP) and the acidification potential (AP) of the system. The GWP for the system is 2000 g carbon dioxide equivalent and the AP, 0.15 g equivalents of hydrogen ion equivalent per kilogram of hydrogen produced. The GWP and AP of this process are one-sixth and one-third, respectively, of those for the hydrogen production by steam reforming of natural gas, and are comparable to producing hydrogen from wind- or hydro-electricity powered conventional electrolysis.     

The issue-attention cycle: a question of impact on energy conservation policy in West Germany

In the 1970s energy was one of the most prominent political topics — in the 1980s it has been replaced as the major debate by employment, microelectronics, the environment and the search for peace. The implementation of energy conservation programmes decided upon at the height of the energy debate is, however, still underway and only partly successful. The impact of the changes in the general political climate upon energy conservation policy in the 1980s will be analysed and discussed with special reference to West Germany.     

Life cycle energy,environment and economic assessment of soybean-based biodiesel as an alternative automotive fuel in China

Life cycle energy, environment and economic assessment for conventional diesel (CD) and soybean-based biodiesel (SB) in China was carried out in this paper. The results of the assessment have shown that compared with CD, SB has similar source-to-tank (StT) total energy consumption, 76% lower StT fossil energy consumption, 79% higher source-to-wheel (StW) nitrogen oxides (NO_X) emissions, 31%, 44%, 36%, 29%, and 67% lower StW hydrocarbon (HC), carbon monoxide (CO), particulate matter (PM), sulfur oxides (SO_X), and carbon dioxide (CO₂) emissions, respectively. SB is thus considered to be much more renewable and cleaner than CD. However, the retail price of SB at gas stations would be about 86% higher than that of CD without government subsidy according to the cost assessment and China had to import large amount of soybean to meet the demand in recent years. Therefore, although SB is one of the most promising clean and alternative fuels, currently it is not a good choice for China. It is strategically important for China to diversify the feedstock for biodiesel and to consider other kinds of alternative fuels to substitute CD.     

Life cycle assessment of photovoltaic electricity generation

The paper presents the results of a life cycle assessment (LCA) of the electric generation by means of photovoltaic panels. It considers mass and energy flows over the whole production process starting from silica extraction to the final panel assembling, considering the most advanced and consolidate technologies for polycrystalline silicon panel production. Some considerations about the production cycle are reported; the most critical phases are the transformation of metallic silicon into solar silicon and the panel assembling. The former process is characterised by a great electricity consumption, even if the most efficient conversion technology is considered, the latter by the use of aluminium frame and glass roofing, which are very energy-intensive materials. Moreover, the energy pay back time (EPBT) and the potential for CO₂ mitigation have been evaluated, considering different geographic collocations of the photovoltaic plant with different values of solar radiation, latitude, altitude and national energetic mix for electricity production.     

Life cycle assessment and evaluation of energy payback time on high-concentration photovoltaic power generation system

In this study, the environmental load of photovoltaic power generation system (PV) during its life cycle and energy payback time (EPT) are evaluated by LCA scheme. Two hypothetical case studies in Toyohashi, Japan and Gobi dessert in China have been carried out to investigate the influence of installation location and PV type on environmental load and EPT. The environmental load and EPT of a high-concentration photovoltaic power generation system (hcpV) and a multi-crystalline silicon photovoltaic power generation system (mc-Si PV) are studied. The study shows for a PV of 100 MW size, the total impacts of the hcpV installed in Toyohashi is larger than that of the hcpV installed in Gobi desert by 5% without consideration of recycling stage. The EPT of the hcpV assumed to be installed in Gobi desert is shorter than EPT of the hcpV assumed to be installed in Toyohashi by 0.64 year. From these results, the superiority to install PV in Gobi desert is certificated. Comparing with hcpV and mc-Si PV, the ratio of the total impacts of mc-Si PV to that of hcpV is 0.34 without consideration of recycling stage. The EPT of hcpV is longer than EPT of mc-Si PV by 0.27 year. The amount of global solar radiation contributing to the amount of power generation of mc-Si PV is larger than the amount of direct solar radiation contributing to the amount of power generation of hcpV by about 188 kW h/(m² year) in Gobi desert. Consequently, it appears that using mc-Si PV in Gobi desert is the best option.     

Implementation of energy efficiency standards of household refrigerator/freezer in China: Potential environmental and economic impacts

Due to the rapid economic development, living standards in China are improving fast. Chinese families are having more household electrical appliances, among which refrigerators are indispensable. Energy consumption of refrigerators is huge in China and causes environmental concerns. China has issued the national energy efficiency standards of household refrigerators, GB12021.2-2003 and GB12021.2-2008 to promote high-efficiency refrigerator production and use. This study evaluated the impacts of the standards on the environment, manufacturers and consumers over a long-term period of 2003–2023. It first evaluated the potential electricity conservation and GHG emission reduction resulting from energy efficiency improvements driven by the standards. Next, manufacturers’ technological and economic concerns about complying with the standards were discussed. Some efficiency improving design options were considered and the resulting increases in manufacturing cost and retail price were estimated. The return of consumers from invest in efficiency was analyzed based on lifecycle cost saving of the improved models. The economical viability of the standards was then evaluated by national consumer costs and benefits. Results showed that the considered efficiency standards will potentially save a cumulative total of 588–1180 TWh electricity, and reduce emission of 629–1260 million tons of CO₂, 4.00–8.04 million tons of SO_x and 2.37–4.76 million tons of NO_x by 2023, depending on sale share of models by efficiency. In a more environmentally optimal case (75% sale share of high-efficiency models), the national consumer benefits are 121 billion RMB (discounted), with the benefit/cost ratio of consumer’s expenditure being 1.45:1. However, the preference to high-efficiency models is substantial influenced by consumer’s expectation on return from the additional cost on efficiency.     

Potential problems and limitations of energy conservation and energy efficiency

We discuss that whilst energy conservation and energy efficiency both ultimately have the same goal they attempt to achieve this via very different approaches. We then discuss how both options face significant barriers to ultimately successfully reduce electricity consumption.     

Life cycle analysis and cost of a molten carbonate fuel cell prototype

The LCA is a method enabling the performance of a complete study on the environmental impacts of the product, taking into consideration all its life cycle (“from the cradle to the tomb” or, better “from the cradle to the cradle” when also the maximum recycling/reusing of the materials is provided. There are many procedures to perform an LCA of the consumers’ products. In particular, the SUMMA method (Sustainability Multi-criteria Multi-scale Assessment) allows obtaining a number of indices of efficiency and environmental sustainability which make the LCA assessment much more complete and significant. LCA method often represents the basis for an additional assessment of industrial products and processes, the LCC (Life Cycle Costing) which, allowing the association of economic variables to any phase of the life cycle, represents a useful tool for financial planning and management. The case study analysed in the present work concerns an LCA analysis, using the SUMMA method and the LCC of one small size molten carbonate fuel cell, 2.5 kW, assembled in the Fuel Cells Laboratory within the Educational Pole of Terni at the Università degli Studi di Perugia. For sake of completeness of the results, the methods Ecoindicator99 and Impact2002 + were used in the analysis, as implemented in the used calculation software, the SimaPro 7.1 by PRè Consultants. From the registered results, it emerges that the environmental energy sustainability of the analysed element enables its widespread and in-depth employment in the phase subsequent to the optimisation of the connected economic frame; the scenarios opened by the present work envisage great margins of improvements of said aspects in the future experiments.     

Life cycle environmental loads and economic efficiencies of apartment buildings built with plaster board drywall

Due to the ease of remodeling apartment buildings, as well as the increased lifespans and performances required of apartment buildings, the demand for new plaster board drywall materials with outstanding flexibility is growing, and the importance of assessing the associated environmental load is increasing. This study evaluates the CO₂ generated during the life cycle of a building (LCCO₂) and its economic efficiency to assess the environmental loads and costs of buildings that use plaster board drywall.A typical concrete bearing wall structure for an apartment building was defined as case 1, and comparisons were performed with alternative samples (cases 2, 3, and 4) containing different ratios of plaster board drywall on top of case 1. The structural safety of each sample building was considered along with the legal incentives according to the use of variable type wall. In addition, life cycle assessments of both CO₂ and economic efficiency were conducted according to stage, including the construction stage, operation/maintenance stage, and demolition/waste stage. Data including quantity of construction material, amount of energy usage, repair rate, and repair period (all of which are required during each stage of assessment) were utilized for the assessment of both CO₂ and economic efficiency.As a result, in flat-type structures, the CO₂ reduction rates of cases 2, 3, and 4 compared to case 1 were 1.0%, 4.5%, and 5.4%, respectively. In the assessment of cost, the reduction rates compared to case 1 were −0.01%, 5.8%, and 6.0%, respectively. Also, in the tower-type structure, the CO₂ reduction rates of cases 2, 3, and 4 compared to case 1 were 1.3%, 4.9%, and 5.5%, respectively. In cost assessment, the reduction rates compared to case 1 were −1.1%, 3.3%, and 3.5%, respectively.     

Life cycle cost analysis of alternative vehicles and fuels in Thailand

High crude oil prices and pollution problems have drawn attention to alternative vehicle technologies and fuels for the transportation sector. The question is: What are the benefits/costs of these technologies for society? To answer this question in a quantitative way, a web-based model (http://vehiclesandfuels.memebot.com) has been developed to calculate the societal life cycle costs, the consumer life cycle costs and the tax for different vehicle technologies. By comparing these costs it is possible to draw conclusions about the social benefit and the related tax structure. The model should help to guide decisions toward optimality, which refers to maximum social benefit. The model was applied to the case of Thailand. The life cycle cost of 13 different alternative vehicle technologies in Thailand have been calculated and the tax structure analyzed.     

Life cycle energy consumption and GHG emissions of hydrogen production from underground coal gasification in comparison with surface coal gasification

Developing underground coal gasification (UCG)-based hydrogen production (UCG-H₂) is expected to alleviate hydrogen supply and demand contradiction, but its energy consumption and environmental impact need to be clarified. In this paper, comparative study of energy consumption and greenhouse gas (GHG) emissions between UCG-H₂ and typical surface coal gasification (SCG)-based hydrogen production (SCG-H₂) is carried out using life cycle assessment method. Result shows energy consumption of UCG-H₂ is only 61.2% of that of SCG-H₂, which is 1,327,261 and 2,170,263 MJ respectively, reflecting its obvious energy saving advantage. 80% capture rate can achieve an appropriate balance between energy consumption and emissions. Under this capture rate, emissions of UCG-H₂ and SCG-H₂ are roughly equivalent, which are 207,582 and 197,419 kg CO₂-eq respectively. Scenario analysis indicates energy consumption in hydrogen industry can reduce by 38.8% when hydrogen production is substituted by UCG with CCS to fully meet demand of 21 Mt in 2030.     

Life cycle analysis of processes for hydrogen production

Hydrogen is considered to be an ideal energy carrier in the foreseeable future and can play a very important role in the energy system. A variety of technologies can be used to produce hydrogen. One of the most remarkable methods for large-scale hydrogen production is thermo-chemical water decomposition using heat energy from nuclear, solar and other sources. Detailed simulations of the two most promising water splitting thermo-chemical cycles (the Westinghouse cycle and the Sulphur-Iodine cycle) were performed in Aspen Plus code and obtained results were used for life cycle analysis. They were compared with two different processes for hydrogen production (coal gasification and coal pyrolysis). Some of the results obtained from LCA are also reported in the paper.     

Load and energy requirements in residential buildings in Saudi Arabia: A comparative study

The load and energy requirements in residential buildings vary according to a number of factors. One of these factors is the geographical location in which the building is situated. Using a detached single-family house, the DOE2.1C load and energy analysis program was used to investigate the effect of the geographical location on the load and energy requirements. Four different cities, namely Dhahran, Riyadh, Jeddah and Khamis-Mushayt, representing four different climatic locations, are considered in this study. The analysis shows that the building parameters having the greatest impact on load are conduction through walls and roof, glazing area and infiltration level. The capacity requirements of the equipment and the total energy requirement for year-round air conditioning were calculated for a house in each city. A comparison shows that the city of Khamis-Mushayt has the lowest energy consumption and Jeddah has the highest energy consumption. The equivalent uniform annual cost (EUAC) method was also used to compare the economic performances of typical houses in the four cities. The comparison shows that the district of Khamis-Mushayt has the lowest EUAC, but the difference between the other cities is not significant. Furthermore, it shows that there is a significant difference between the government's and customers' EUACs.