報告書番号

Y13011

タイトル（和文）

米国における電力自由化後の供給力確保に関する制度の比較分析

タイトル（英文）

Comparative Analysis of Institutional Approaches for Ensuring Resource Adequacy after Restructuring of Electricity Market in the US

概要 （図表や脚注は「報告書全文」に掲載しております）

米国では，電力の自由化後，電源投資の資金調達の問題や卸電力市場の構造的な問題で，電源投資が行われにくい状況にあり，十分な供給力確保のため，様々な制度的アプローチを採ってきた。極端に高い卸電力価格を許容してきたテキサスでは，予備率の著しい低下が見込まれており，短期の価格シグナルが機能しない「市場のリスク」がある。容量市場を創設してきた北東部では，容量の価格に影響を与える複雑な制度設計で今も試行錯誤が続いており，「制度設計のリスク」を抱えている。規制の下での電源入札制度を活用してきたカリフォルニアでは，投資が積極的に進められたが，予備率は目標値を大幅に上回り，規制当局主導の計画によって設備形成が非効率となる「規制のリスク」が顕在化している。わが国の供給力確保の仕組みの創設では，こうした様々なリスクを認識して，慎重かつ柔軟な制度設計を進めていくことが重要である。

概要 （英文）

In the U.S., ensuring resource adequacy is an important policy objective in restructuring of electricity industry. New generation capacity investment has been faced with difficulties associated with securing financing without long-term power purchase agreement and so called "missing money" problem in the wholesale energy market. Since there are several institutional approaches to solve these problems, it is important for Japan to learn lessons from the experiences of these different approaches to ensure resource adequacy after the reform. In Texas, where energy-only market approach is taken, reserve margin is expected to be low in the future. Relying on occasional price spikes in wholesale electricity market is not only increasing risks but it is inherently difficult to differentiate scarcity pricing from price manipulation by dominant generators with market power. In the Northeast, ISO/RTOs operate centralized capacity markets. Although the capacity market helps ensuring resource adequacy, the market design is so complex that it is inevitable that the parameters for the market are subject to constant reviews by stakeholders. In California, the regulator offers long-term contracts through regulated electricity distribution utilities to support new investment. While its resource adequacy program was successful in attracting new investment, it has resulted in excess capacity, indicating that it is subject to regulatory risk. In addition, it is not consistent with retail market liberalization. In the case of California, It is important to recognize that the market mechanism may not bring benefits to the society unless the risk of institutional design is well managed.

報告者

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