報告書番号

Y99014

タイトル（和文）

確率的フロンティア分析による日米電気事業の生産性比較 -汽力発電所と送配電部門を対象として-

タイトル（英文）

Relative Performance of US and Japanese Electric Utilities-An Application of Stochastic Frontier Analysis-

概要 （図表や脚注は「報告書全文」に掲載しております）

わが国の電気事業の生産性や効率性に対する関心は高いものの、その国際比較を詳細に行った研究はまだ少ない。そこで本研究では、日本と米国の私営垂直統合型電力会社の1990年から1997年までのデータを利用して、汽力発電所と送配電部門における生産性を確率的フロンティア分析と呼ばれる手法を用いて比較分析を行った。その結果、汽力発電所においても送配電部門においても、日本の電力会社が経営形態の比較的近い米国の電力会社と比べて非効率が大きいとはいえず、高い効率性を維持してきた可能性が示唆される。ただし、送配電部門においては日本の電力会社の毎年の技術進歩率は米国を下回っており、効率性を改善する余地も出てきている。汽力発電所の効率性の格差はほぼ一定で、技術進歩率は両国とも小さく、大きな差がなかった。

概要 （英文）

Although the electricity industry in Japan has been an object of efficiency and productivity analysis for a long time, only few attempts have so far been made at international comparison. This paper estimates and compares productive efficiency of U.S. and Japanese electric utilities during 1990-1997 using a stochastic frontier approach. Our focus is on steam power production and network services (transmission and distribution) of major vertically integrated, investor-owned utilities. We employ a translog production function to represent the technology of steam power production and a translog labor requirement function for the technology of network services. For the network services, we have several alternative models with respect to outputs and inputs other than labor. Applying the stochastic frontier analysis to panel data, we examine the temporal pattern of relative (technical) efficiency and technical change. For steam power production, we also estimate Malmquist productivity index. Empirical results from various specifications of the stochastic frontier (one of which allows mean inefficiency to vary between the two countries) show that Japanese electric utilities are relatively more efficient in both steam power production and network services. The differences in relative efficiency in steam power production between the two countries are about the same during the sample period, while the inefficiency of Japanese utilities in network services has been increasing since 1995. The technical progress in steam power production for the sample period is very small in both countries, if any. The rate of technical progress in network services is higher for US electric utilities than for Japanese utilities.

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