報告書番号

Y10023

タイトル（和文）

東京都排出量取引制度の実効性について －欧米の経験を通じた考察－

タイトル（英文）

Ex-ante evaluation of Tokyo Cap-and-Trade Program - Key design of the program, lessons learnt from ongoing programs in the U.S. and Europe -

概要 （図表や脚注は「報告書全文」に掲載しております）

本稿では，（1）費用効果的な削減，（2）取引費用の削減，（3）削減目標の達成の三つの視点から，東京都において2010 年4 月に開始された，大規模事業所に対する温室効果ガス排出総量削減義務と排出量取引制度（「新制度」）について検討した．先行事例として，欧米において導入・運用されてきた汚染物質の排出抑制のための施策，具体的には，米国のSO2 およびNOx 排出権取引制度，欧米のCO2 排出権取引制度を取り上げ，これらの制度の運用で明らかとなった排出権取引制度の課題を整理した．その上で，東京都の新制度がこうした課題にどのように対応しているのかをみることにより，制度の特徴や設計上の留意点を検討した．

概要 （英文）

This paper examines challenges of Tokyo Cap-and-Trade Program from the following viewpoints; i) cost-effective CO2 emissions abatement, ii) reduction in transaction costs, and iii) achievement of a numerical target. Firstly as for the cost-effective abatement, effectiveness of the program deeply depends on price effects of ETS, which are not clearly proved in the previously introduced programs such as those in the U.S. and Europe, partly because energy efficiency barriers often hinder cost-effective measures. In Tokyo, however, price effects may work owing to previous so-called CO2 abatement program, which had effectively addressed these barriers. However this fruit of the previous program will vanish in the future, as current scheme does not directly address energy efficiency barriers. Distortion of price effects is another issue, which gives favorable treatment to less effective measures such as solar energy and cogeneration. Secondary as for transaction costs, an ETS can leave severe impacts especially on small business institutes and those with limited room for energy saving. Considering that Tokyo's program covers relatively small institutes, proper coverage will be an important issue. Finally as for numerical targets, a previously-set cap can be modified according to built-in provisions such as baseline reexamination and off-sets mechanisms. Therefore it needs to be carefully examined whether the target shall be achieved, as it highly depends on detailed design and operations of the program.

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