Objective. The objective of this review article is to understand the current status of the development of scenario analysis methodologies applying LCA, and scenario-based LCA.
Results and Discussion. Scenario analysis is increasingly utilized in LCA related studies. This echoes need of introducing life cycle thinking in a wider dimension of decisions that require participation of multiple stakeholders. Scenario analysis naturally deals with future situations, and introduces time dimensions in the analysis. Thus, both inventory and impact assessment stages require enhancements. In this article, the status quo of such discussions is reviewed. In addition, use of life cycle thinking to generate scenarios in scenario analyses for technology innovation is introduced to demonstrate the wider potential of LCA in non-LCA studies.
Conclusions. The review shows several new directions in the research needs in the field of Scenario-based Life Cycle Assessment.
Purpose. Consequential LCA（CLCA）is becoming widely used in the scientific community as a modelling technique which describes the consequences of a decision. However, despite the increasing number of case studies published, a proper systematization of the approach has not yet been achieved. This paper investigates the methodological implications of CLCA and the extent to which the applications are in line with the theoretical dictates. Moreover, the predictive and explorative nature of CLCA is discussed, highlighting the role of scenario modelling in further structuring the methodology.
Methods. An extensive literature review was performed, involving around 60 articles published over a period of approximately 18 years, and addressing both methodological issues and applications. The information was elaborated according to two main aspects: what for（questions and modes of LCA）and what（methodological implications of CLCA）, with focus on the nature of modelling and on the identification of the affected processes.
Results and discussion. The analysis points out that since the modelling principles of attributional LCA（ALCA）and CLCA are the same, what distinguishes the two modes of LCA is the choice of the processes to be included in the system（i. e., in CLCA, those that are affected by the market dynamics）. However, the identification of those processes is often done inconsistently, using different arguments, which leads to different results. We suggest the use of scenario modelling as a way to support CLCA in providing a scientifically-sound basis to model specific product-related futures with respect to technology development, market shift, and other variables.
Conclusions. The CLCA is a sophisticated modelling technique that provides a way to assess the environmental consequences of an action/decision by including market mechanisms into the analysis. There is still room for improvements of the method and for further research, especially in relation to the following aspects: clarifying when and which market information is important and necessary; understanding the role of scenario modelling within CLCA; and developing a procedure to support the framing of questions to better link questions to models. Moreover, we suggest that the logic of mechanisms could be the reading guide for overcoming the dispute between ALCA and CLCA. Going further, this logic could also be extended, considering CLCA as an approach – rather than as a modelling principle with defined rules – to deepen LCA, providing the conceptual basis for including more mechanisms than just the market ones.
Scenario planning is the useful strategic planning tool in the uncertain age. Developed by Royal Dutch Shell in 1970s, it deals with multiple plausible futures, fostering objective thinking among strategy planners. It also triggers constructive dialogue among multiple stakeholders by having them suspend their beliefs. By focusing on the future uncertainties and multiple aspects to form the future states, scenarios delineate the futures vividly in the form of narratives. Due to those details, people involved in scenario planning can discuss right strategic direction easily. It is a powerful planning tool, especially for public theme such as environmental issues since it fosters immediate actions to create a better future by identifying critical issues to overcome and pitfalls to avoid well in advance.
Objective. The objective of this article is to provide the readers with a general knowledge about the energy system model MARKAL, which has been used in many technology evaluation and scenario studies worldwide.
Results and Discussion. In the first place, MARKAL variants supported by Energy Technology Systems Analysis Program（ETSAP）are described briefly. The outline of AIST version MARKAL, which is a Japanese version standard MARKAL, is the second topic. Finally, two recent studies conducted by using AIST MARKAL are shown as example.
Conclusions. This article shows what MARKAL model is and how it is used for scenario studies.
Objective. Scenario building has widely been used to help make decisions in an uncertain world. Nowadays it is often applied to sustainability issues, such as the IPCC’s greenhouse gas emissions scenarios, aiming to delineate possible images of, and pathways to, a sustainable society. Many researchers have developed methods and tools for scenario building activities. However, few papers have discussed research agendas regarding the support of scenario building. Based on a literature review of existing studies, this paper aims to clarify requisites and challenges for supporting scenario building, especially in the context of sustainability issues.
Results and Discussion. A scenario is, in general, created through iterative cycles composed of three steps; i. e.,（a）idea generation,（b）idea integration and scenario description, and（c）scenario evaluation. Focused on existing scenarios dealing with sustainability issues, quantitative simulations are often used to underpin scenario descriptions. Given a scenario is used as a means of generating and communicating ideas by involving multiple participants, the paper identifies requirements for helping the participants undertake the steps（a）-（c）for scenario building. The requirements here include:（i）to represent a scenario in a way that allows for a common understanding among the participants,（ii）to provide methods and tools for executing the processes of the steps（a）-（c）, and（iii）to make existing scenarios and their associated simulators reusable in order to encourage developing new scenarios. The results of our literature review show that a number of methods and tools are available to support some parts of the three steps（a）-（c）. Nevertheless, there are several challenges remaining to approach research tasks（i）-（iii）. As a trial toward a holistic support of scenario building, a brief introduction is given regarding Sustainable Society Scenario（3S）Simulator, which is a system developed by the authors to help scenario designers create and analyze scenarios. 3S Simulator enables to clarify the logical structure of scenarios for a better understanding, and accumulate various scenarios and simulators with the aim to promote the development and what-if analysis of new scenarios.
Conclusions. The paper reviews existing studies relevant to the support of scenario building. Although many useful methods and tools exist, there are research issues to be further addressed in supporting scenario building. For example, it is needed to ensure the transparency of the underlying logics of scenarios to facilitate communication among participants involved. In addition, the accumulation of knowledge should be promoted in the form of scenarios and simulators, while many researchers in the LCA community are engaged in developing a variety of quantitative simulation models, such as material flow models and input-output models.
The objective of this paper is to introduce the practice of scenario planning in Royal. Dutch. Shell Group. Discussed in detail is the framework and contents of “New Lens Scenario, 2013”. This paper aims at offering first hand materials accrued by long-time practitioner in Shell scenario team, the author, to academia and general public.
The objective of this article is to describe the latest trends and requirements for the scenario analysis of electric energy. A power system has been evolving so as to realize sustainable demand and supply of total energy where economy, security of supply, reduction of environmental impacts are targeted. On the demand side, in addition to the essential energy efficiency, electrification is the major resource for energy efficiency. EV and heat pump water heater, electrification of mobility and heat supply, offer the possibility of demand shift（demand activation）. On the supply side, the output of some of the major renewable energy sources such as photovoltaic and wind generation have a nature of variability and uncertainty due to fluctuation of sunshine and wind velocity. The variable and uncertain features of renewable generation gradually occur challenges of an operation of a power system according as their penetration increases, and additional balancing capability（flexibility）of a power system are required as the penetration of the variable renewable generations. In a power system there are several possibilities of flexibility of traditional generation fleet, modification of renewable generation, demand activation, energy storage, and interconnections between power systems. In a power system the enhanced operation methodologies is being established through the integration of flexibilities and renewable energy generation forecast including operation of wholesale and retail power market. The scenario analysis of electric energy is supposed to include the features and requirements of a power system including a functionality to be a sophisticated communication tool between stakeholders to analyze problems with complication and uncertainty.
Objective. The objective of this paper is introduction of “Low Carbon Society Scenarios” in the world, Asia and Japan.
Results and Discussion. The long term target for the global mean temperature is set to be lower than 2 degree centigrade compared to the pre-industrial level, and the IPCC 5th Assessment Report introduced the emission levels in 2050 and 2100 to achieve this target. In order to achieve the emission target, the mitigation pathways in Asia and Japan were investigated under the research programs of the Environment Research and Technology Development Fund, the Ministry of the Environment. For Asian region and Japan, the 10 actions and the 12 actions were proposed, respectively. Although the mitigation targets in Asian countries are not sufficient to achieve the 2 degree target, some of the countries have attempted to assess the mitigation actions toward the 2 degree target using their own integrated assessment model. In the case of Japan, the low carbon society scenarios in 2050, and the corresponding mitigation target in 2020, have been assessed quantitatively. After the East Japan Great Earthquake, the mitigation target for 2020 is revised to 3.8% reduction compared to the 2005 level under the condition of zero electricity generation from nuclear power plants. From the viewpoint of long-term target of Japan, this new target for 2020 does not seem to be sufficient.
Conclusions. The Low Carbon Society Scenarios have been globally shared, but actual pathways toward the low carbon society are not yet concrete. In order to realize the Low Carbon Society, we will have to take substantial measures immediately.
This article introduced examples of the development of multiple scenarios on resource cycling and waste management. Various factors discussed in the course of these scenario development were examined, particularly factors that can strongly affect future resource cycling and waste management. Then the relations among these factors and LCA were described. Examples of the development of multiple scenarios on resource cycling and waste management include the development of ‘reference scenarios’ showing potential changes in the socio-economic environment in the future, the development of ‘policy scenarios’ showing potential policies according to ‘visions’ as objective conditions, and the development of both as packages. These scenarios should be developed according to their respective purposes. However, ‘reference scenarios’ are necessary for the development of ‘policy scenarios’. Based on these examples, the following factors are inferred as important for future resource cycling and waste management: changes in ‘industries’, ‘trade schemes’, ‘legal schemes and regulations’, ‘local government finances and systems’, ‘resource prices’, and ‘technology’. These factors should be considered when establishing a system of analytical subjects and developing scenarios in LCA. Causal relations among various factors that are used for the development of reference and policy scenarios are also very useful when conducting consequential LCA.
Objective. Modern wooden houses are constructed from various materials, some of which result in high CO2 emissions during factory production. We have to clearly understand the environmental impact of modern wooden houses. Most researchers focus only on CO2 emissions from energy consumption in a household after construction. There is little research focused on the CO2 emissions from actual home construction. Most researchers in Japan calculate CO2 emissions using construction material measurements from housing blueprints. However, these values are not accurate. These inaccuracies stem from the difficulty in calculating the total weight of construction materials from blueprints. This leads to a difference between the weight based on actual measurements and the estimated weight based on calculations. We measured all weights of the construction materials and waste. We chose four target houses: one high-foundation wooden house (House A), two two-story wooden houses (Houses B and C) and one three-story wooden house (House D). We compared the weight of construction materials and waste between these four houses. Next, we calculated CO2 emissions using the weight in construction materials we measured. Results and Discussion. We obtained the weight of four houses, accurate data of construction material and waste. The number of different construction materials used for the target houses was between 840 and 1525. House A’s weight per floor of construction materials and waste were 997.4kg/m2 and 12.9kg/m2, respectively. House B’s weight per floor of construction materials and waste were 751.5kg/m2 and 14.2kg/m2, respectively. House C’s weight per floor of construction materials and waste were 707.1kg/m2 and 24.9kg/m2, respectively. House D’s weight per floor of construction materials and waste were 725.0kg/m2 and 24.3kg/m2, respectively. We compared the weight in construction materials per construction area for every job type. Most of these values varied because of the differences in house specification. The four values of interior finish work were close. The amount of CO2 emissions due to construction materials could then be calculated depending on the exact weight. Conclusions. We clarified the actual weight in construction materials and waste for the four houses. We were able to calculate CO2 emissions based on the actual weight. In order to more fully understanding, we must now gather more data from other construction companies.
Objective. The objective of this paper is to analyze the effect of GHG accounting for each sector by industrial and urban symbiosis system. GHG accounting to calculate Scope 1,2,3 is a buzz word in the field of LCA, but accounting method of recycling system have not been discussed fully. We designed non-recycling scenario and industrial and urban symbiosis scenario to estimate the Scope of each sector as a case study. Results and Discussion. The results of GHG accounting (Scope1,2,3) showed those value of each sector was fully different as far as the reduction of CO2 of the whole system was stable. Energy intensive industries and waste management sector in municipalities reduced Scope1 though they increased Scope3 slightly. On the other hand, industries emitting industrial waste reduced Scope3 as the result of recycling the emitting wastes. The sum of GHG reduction of each sector would be more than the reduction of the whole system due to double counting. However the aim of GHG accounting is incentive to reduce GHG of each sector, so double counting would be approval.
Although the visualization of the CO2 emission for the menu in the restaurant is thought to be important as the basic data when we consider the sustainable life style, it seems to be almost impossible to calculate them because the energy consumption to cook each menu is not disclosed to the public. In this paper the estimation method for the CO2 emission of the menu in the restaurant is proposed, which is based on the CO2 emission to cook the same menu in the household. First, the CO2 emission of the menu cooked in household was estimated. Second, “the annual CO2 emission per the annual sales”, i.e. “the CO2 emission per yen”, for 9 companies operated as chain-restaurants was calculated using information presented in their CSR reports, and then, the CO2 emission to cook each menu was estimated multiplying “the CO2 emission per yen” by “price of menu”, which correspond to the allocation method of the total energy consumption of the company to each menu based on the monetary, but which is thought to include the CO2 emissions such as for lighting, transportation of foodstuffs and managing/operating company. As the results to compare “the CO2 emission for the menu in the restaurant (for the production of foodstuffs + cooking)” to that in the household, the scale factor from the household to the restaurant was defined to be around 1.42. This method is very rough, but it is useful to estimate the order of magnitude of the CO2 emission of the menu in the restaurant comparing the CO2 emission in the households.
Objective. Global warming is exerting a damaging effect on human health. This damage is not only influenced by future climate conditions, but also projected economic development and population growth. That being said, there are no health damage factors related to CO2 emissions which take into account future socioeconomic scenarios in life cycle impact assessment (LCIA). Thus the purpose of this research is to calculate human health damage factors based on special report on emission scenarios (SRESs) developed by IPCC. Materials and Methods. The procedure used to calculate the SRES-based damage factors is as follows. First, a framework was developed to calculate damage factors based on multiple parameters: rise in temperature, relative risk increase, mortality rate increase, rise in number of deaths, and disability-adjusted life year (DALY) increase. Secondly, these parameters were calculated for each individual SRES based on the relationship among the parameters and CO2 emissions, GDP, and population values of each scenario. Finally, the damage factor for each SRES was calculated by multiplying all the parameters that had been calculated based on the CO2 emission, GDP and population data in the corresponding scenarios. Results and Discussion. Using this method, the human health damage factors for four SRESs (A1B, A2, B1, and B2) were calculated. The damage factors consisted of six different items: malaria, diarrhea, cardiovascular disease, malnutrition, coastal flooding, and inland flooding. The calculated results by scenario were 2.0×10-7, 6.2×10-7, 2.1×10-7 and 4.2×10-7 DALY/kg-CO2, respectively. The damage caused by malnutrition is the greatest, followed by diarrhea. The projected future mortality rate and DALY per death based on future GDP per capita contributed significantly to the differences among the four damage factors, while the difference of temperature rise among scenarios depended on future CO2 emission is not influential to the damage factors. Conclusions. The human health damage factors related to CO2 emissions for four SRESs were estimated. As a result of differences between future socioeconomic scenarios, the largest amount of damage per CO2 emission unit was 3 times greater than the smallest amount. Therefore, sensitive analysis is highly recommended when seeking to compare damage caused by global warming and other impact categories.
Background, Aim and Scope. It is vital to quantify the potential impacts of water consumption for sustainable development. Since water has uneven distributions with time, place, and origin, simple summation of water consumption may mislead as an indicator of the environmental impacts. This paper proposes a concept for weighting uneven distribution of water and characterizing water consumption into potential impacts from viewpoints of hydrology and life cycle assessment. Materials and Methods. The concept for weighting water resources and converting water consumption into potential impacts on freshwater availability was proposed, based on an assumption that the impact is proportional to the catchment land area or time period required to obtain a unit amount of water from each water source. The Water Availability Factor (fwa) was defined based on global mean precipitation by a global hydrological modeling system to reflect the variability of maximum renewable water resources with location and source of water at global resolution 0.5×0.5 degrees. This concept can be understood instinctively and provide various types of characterization factor based on user’s demands. Results and Discussion. The fwa for precipitation (fwap) tended to be smaller than that for surface or groundwater, based on the principle of water balance. Higher values of fwap were found in dry areas such as the Sahara, Arabian Peninsula, South Africa, interior China, the American Midwest and Australia. Three types of weighted average fwa were presented by country, for entire countries, rainfed cropland, and irrigated cropland. Values of fwap for agricultural use tended to be lower than those for entire countries in arid countries. It can be thought that croplands appear more selectively distributed in areas with sufficient water accessibility. Conclusions. The current work showed that the Water Availability Factor can be estimated based on land area or time period required for obtaining a unit amount of water from each source. It can be provided with any spatial resolution such as by grid, continent, country, or basin. The grid-scale data permits local conditions to be depicted and potential impacts evaluated in exacting detail. The result of proposed characterization can be understood intuitively by using the concept of land area or time period required and the global annual precipitation. It is applicable in terms of robustness of the factors, and can be adopted in life cycle impact assessment of freshwater use. Recommendations and Perspectives. There is room for argument regarding the validation of fwa uncertainties, because it is possible that fwa varies considerably with different meteorological forcing data or hydrologic models. Further study to increase temporal resolution of fwa is expected to reflect seasonal differences of renewable water resources. Actual midpoint characterization on a global scale should be performed using this concept. It will facilitate clarification of locations and magnitudes of potential impacts caused by nations, products, and individuals.