報告書番号

Y09031

タイトル（和文）

不確実性下の高経年化原子力発電プラントの投資意思決定手法の開発

タイトル（英文）

Development of an Investment Decision Tool for Aged Nuclear Power Plants under Uncertainty

概要 （図表や脚注は「報告書全文」に掲載しております）

収益性についての不確実性の想定の下に，原子力発電プラントの寿命延伸ないしリプレースの投資オプションを評価する手法を考案し，経年プラントの適切なマネジメントにとって参考となる意思決定ツールを提供する．具体的には，「廃止措置」，「廃止措置後に後継プラントを新規設置（リプレース）」に加えて，既存プラントに大規模補修を加えて性能向上を図る「設備更新」の3 種の投資のうち適切なものを選択するモデルを構築した．モデルの試算によれば，原子力の収益性が高まる，具体的には売電価格が上昇するにつれて，廃止措置→リプレース→設備更新→リプレースと，それぞれの投資戦略の価値の大小関係が入れ替わり，選択される戦略が変化する．さらに，各々の2 つの戦略が切り替わる中間領域では，両者の選択の意思決定を延期することが最適であり得る．以上の試算を通じて，本研究が提案する分析手法及び計算モデルが，対象とする投資選択問題に有益な示唆を与えることが示された．

概要 （英文）

The nuclear power generating stock in Japan, which provides 30% or more of the nationwide electricity supply in recent years, is heading into the era of plant aging as those units over 40 years of operation emerge in 2010 and onward. Under accumulating uncertainties surrounding investment decisions, one of the key questions is how best to manage the existing capacity by choosing a wisest option among dismantling, refurbishment, and replacement. This report attempts to develop a methodology to analyze investment decision on aged nuclear units based on real-option analysis, and then presents illustrative simulation runs to demonstrate functions of the numerical models. Major findings are summarized as follows:
a) When compared with the conventional net present value (NPV) method, the proposed model is capable to deal with uncertainty explicitly by taking volatility in the formula. Also, for the replacement option, one can choose optimal timings of the dismantling and new plant installation independently.
b) As the profitability increases, the model suggests different investment option as optimal, starting from dismantling to replacement, further to refurbishment, and again to replacement as the most basic pattern. Additionally, where two of the strategies have similar values, postponement of both decisions can be optimal.
Through these exercises, the proposed methodology proved itself capable for raising valuable implications to investment decisions in managing the production fleet.

報告者

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