報告書番号

Y03010

タイトル（和文）

電力と二酸化炭素排出権の取引市場によるコスト削減効果 -―取引実験による分析―-

タイトル（英文）

Market Trading Experiments and Analyses of Their Impacts on Gains from Trade

概要 （図表や脚注は「報告書全文」に掲載しております）

電気事業が、電力の供給義務を果たしつつCO2排出量を削減するためには、電源構成の変更や市場取引の活用を図る必要がある。このとき電力会社が直面する新たなリスクやコストの増大等の問題に対応するために、我々は電力とCO2排出権を同時に扱う取引モデルを開発し、改良を重ねてきた。本報告では、この取引モデルを用いて①電力のみの取引、②排出権のみの取引、③電力及び排出権を同時に取引の三つのケース設定で取引実験を行い、取引なしケースと比べた費用削減効果が①電力のみ取引、②排出権のみ取引、③両方取引の順に大きくなることを確認した。実験では、取引機会が増えることで(1)市場全体での新規投資の抑制、(2)両市場での価格変動が小さくなることによる取引リスクの軽減、(3)CO2排出削減目標の遵守企業数の増加、などが顕著な効果として現れ、これらがコストの削減に寄与した。

概要 （英文）

How does CO2 emission trade contribute to reduction of abatement costs? Does this effect vary depending on the scheme designed? With awareness of these issues, we conducted several experiments assuming utility firms as main (and only) players in an emission trading market. Although closed emission market is unfeasible, our simulation is distinctive in the sense that we introduce two complementary markets, characterizing the electricity market as a primary products market and the emissions market as a bi-products market.A company that faces shortage of emission allowances can take following three alternative actions to meet both an emission reduction target and responsibility to meet energy demand, at the same time: (i) to purchase CO2 emission in the emission trading market; (ii) to purchase electricity in the electricity market and reduce power generation; and/or (iii) to install new facilities that generate electricity more efficiently with less CO2 emission. This game is complex because we assume uncertainty of electricity demand and the third option proves to be effective with a designed time lag.Market trades are generally considered to achieve greater efficiency when both electricity and emission allowances are tradable, compared with the situation where either one of the two alone is tradable. Results of experiments show: i) more than 90 percent of firms gain from trade if CO2 allowances become tradable in addition to electricity; ii) two markets function as price stabilizers by complementing each other; ii) an emission reduction target becomes easily achievable by utilizing market trade of either electricity or emission allowances. If both markets are available, it may be more easily achieved; and iv) although few suppliers dominate most quota in the market due to presumption of experiments, we observed very little surplus-profits received by these companies.

報告者

キーワード