An Economic Analysis of Policies for Reducing Global-Warming-Gas Emission in Japan

本研究评估了政府政策，支持太阳能光伏（PV）系统在日本住宅部门的扩散。我们估计了一个结构性的需求和供应模型的光伏系统使用市场水平的数据和模拟的光伏系统的扩散路径，如果过去的政府补贴计划没有提供。模拟结果表明，补贴改变了光伏发电的需求函数，使光伏发电装机量大幅增加。我们还评估了新的上网电价计划，通过模拟几种情况下的电价和预设的未来光伏生产成本。结果表明，上网电价可能有助于扩大光伏系统。然而，它的成本太高，我们发现，在社会福利方面，很难证明上网电价，除非我们最大限度地估计二氧化碳的货币价值。

This research evaluates the government policies in supporting the diffusion of Solar Photovoltaic (PV) systems in the residential sector of Japan. We estimate a structural demand and supply model of PV systems using market-level data and simulate diffusion paths of PV systems if the past government subsidy program had not been offered. The simulation result reveals that the subsidy shifted the demand function ofPV, and increased the amount of PV installed considerably. We also assess the new feed-in-tariff program by simulating several scenarios on electricity pricing and presupposed future production costs of PV. The result indicates that the feed-in-tariff is likely to contribute to expand PV systems. However, it costs too much and we found that, in terms of social welfare, it is difficult to justify the feed-in-tariff unless we estimate the monetary value of CO2 maximally.