報告書番号

Y98003

タイトル（和文）

わが国における原子力発電のコスト構造分析 -電力九社の財務諸表に基づく経済性評価-

タイトル（英文）

Cost Structure Analysis of Commercial Nuclear Power Plants in Japan -Based on Corporate Financial Statements of Electric Utility Companies-

概要 （図表や脚注は「報告書全文」に掲載しております）

電力会社九社の財務諸表に基づいて、わが国の原子力発電のコスト構造についての評価分析を試みた。原子力発電コスト（kWhあたり）は、1980年代後半以降は連続的に低下し、他電源と比較して経済的優位性はむしろ高まっている。その原因として、kWhあたりの資本費、とりわけ支払利息の低下が挙げられる。他方、運転管理費と燃料サイクル費の原子力発電コストに占める割合は、増加傾向にあり、それらの費用の相対的重要性が増してきている。この結果から、資本費については、今後多数の新規建設等がない限り、長期的に徐々に低下し続けるものと考えられる。しかし、既存プラントの高経年化に伴って運転管理費とくに修繕費が、および不確実な要素が多い燃料サイクル費が、各々今後上昇する可能性が考えられ、今後の原子力発電の経済性を良好に維持していくためには、これらの費用に対して十分に注意を払う必要がある。

概要 （英文）

As the Japanese electric power market moves toward the deregulation in recent years, the cost reduction becomes a more imperative issue for the electric utility industry. Given this and as the number of new orders of nuclear power plants is declining toward the future, it is becoming more important for corporate management to assess the real trends of cost structure of existing nuclear power plants, instead of estimated cost of model plant, to keep its competitiveness. We therefore analyzed past and current cost structure of commercial nuclear power plants in Japan based on annual corporate financial statements reported by the Japanese electric utility companies from 1971 to 1996. The conclusions of this study are summarized as follows. (1) Nuclear power generation cost has remained stable since 1980. Although it was higher than other power generation in 1988-1989, since then it has been declining. (2) The main reason for this decline is decrease of capital cost, in particular, interest payment. (3) The shares of capital cost excluding interest payment and O&M cost in total nuclear power generation cost have increased steadily throughout the past 26 years. (4) Although total repair expenses have increased continuously throughout the past, repair cost per kWh has remained stable since 1980. (5) Fuel cycle cost is greatly influenced by the fuel cycle back-end cost, especially reprocessing cost. Based on these findings, we conclude that cost estimate based on financial statements is worthwhile. Unless there will be many new construction of power plants, rise of interest rate or replacement of large equipment, capital cost will continue to decline as it did in the past. On the other hand, as the vintage of nuclear power plants in operation grows older, O&M cost, especially repair expenses, is rather likely to increase, as well as fuel cycle back-end cost, which is associated with many uncertainties. Although such upward trends are not identified in this study, electric power companies should take more efforts to reduce these costs in order to keep competitiveness of nuclear power in Japan toward the future.

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