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Research paper : Modeling the social acceptance of industrial technologies (M. Matsumoto et al.)−31−Synthesiology - English edition Vol.2 No.1 (2009) The maximum number of diffusion of energy-saving air conditioner was set at approximately 130 million, which was the number of current diffusion of home-use air conditionersNote 5). For innovation coefficient and imitation coefficient, coefficient values (Table 2) extracted from past diffusion curves of air conditioners were used. We applied the learning curve model, and assumed that the 50,000 yen price difference between eco-products and traditional products contracts by learning curve constant 0.1. The effect of CO2 reduction per diffusion of one eco-product was 115 kg-CO2/year by converting 8,000 yen difference in electricity cost. These are summarized in Table 3.Three scenarios of granting subsidy money to energy-saving air conditioner were set. We assumed subsidy of 20,000 yen per conditioner. First scenario was provision of subsidy from FY 2008 to 2030, and this was compared with basic case to investigate the effect of the subsidy. Second and third scenarios were subsidy provision period from FY 2008 to 2013 and FY 2015 to 2020, and the effects of periods of subsidy provision were compared.7.2 ResultsFigure 8 shows the distribution of consumer preference in basic case and subsidy provision case. In the basic case, of the 1,112 sample consumers (conjoint analysis respondents), there were 675 consumers who preferred energy-saving air conditioner to traditional air conditions (consumer i that satisfied Ui, EAC – Ui, TAC > 0) (H0 = 675/1112 = 0.61). About 60 % of the consumers preferred energy-saving air conditioner (Fig. 8). The preference distribution when the product price decreased 20,000 yen due to subsidy was Ht = 751/1112 = 0.68 (Fig. 8).Using these data in equation (4), the diffusion transition of energy-saving air conditioner was simulated. The result is shown in Fig. 9. In the basic case, eco-product reached 49 % (64 million conditioners) in year 2020, 87 % (110 million conditioners) in 2030, and reached saturation in 2040. The effect of CO2 reduction by diffusion was 7.4 million ton-CO2 in 2020, and 14 million ton-CO2 in 2040. In the subsidy scenario (2008-2030), diffusion was 57 % (74 million conditioners) in 2020 and reached 92 % (120 million conditioners) in 2030.In case the subsidy period was 2008-2013 and 2015-2020, diffusion reached almost same number for both cases after 2020. However, since diffusion occurred earlier in the former case, the number of subsidized air conditioners would be less than the latter case. The total number of subsidies in former case would be about 2/3 of the latter case, and the burden of cost was also 2/3. The result indicated that the provision of subsidy was more efficient when started in the early stage of diffusion.8 Result and issuesA model of social acceptance of eco-products that contribute to global warming countermeasure was constructed. We aim to develop this research further, and to use this model as a component of the larger model of interaction of technology and society.One of the issues of this research is the investigation of adequacy of the integration method (equation (4)) of the Bass model and consumer preference model that was hypothesized in this research. It is necessary to consider the method to verify the adequacy of the integration method from the perspective of projection accuracy. Second, since the objective of this study was long-term diffusion analysis, the model was created based on the Bass model, and setting of diffusion coefficients (p, r, and N of equation (4)) were done in reference to the diffusion coefficients of past similar products. In this research, the person conducting the analysis selected the similar products, but it is desirable to have a standard for similarity. We shall consider some guideline for selecting products to be references of coefficient values.In the future, we aim to develop the model of interaction of technology and society by including corporate decision-making, results of government policy on industrial technology, and social impact assessment of public research institutes[11] that were not included in this model.20002040203020202010208060400100Basic caseSubsidySubsidy : 2008-2013Subsidy : 2015-202012010080604020012340-1-2-3-4Basic caseSubsidy scenarioFig. 8 Distribution of consumer preference.Horizontal axis: Ui, EAC − Ui, TAC; vertical axis: number of people (total 1,112 people).Fig. 9 Result of diffusion analysis for energy-saving air conditioner.Vertical axis: % (100 % is 130 million conditioners, and CO2 reduction effect at that moment is about 15 million t-CO2 (over 1 % of total CO2 of Japan)).

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