報告書番号

Y98013

タイトル（和文）

わが国電気事業の部門別効率性の時系列分析

タイトル（英文）

Intertempral Efficiency Analysis of Japanese Electric Utilities --Efficiency of Generation, Network and Administration Sectors--

概要 （図表や脚注は「報告書全文」に掲載しております）

電気事業における規制緩和を背景に、わが国一般電気事業者はこれまで以上の経営効率化が求められており、その成果の計測方法も重要な課題となっている。本稿では、より実態に即した時系列的な技術効率性計測のために、各主体の技術非効率を考慮しつつ、時系列的な分析を可能とするマルムキスト指標を使用し、わが国一般電気事業者9社の部門別の効率性分析を行うとともに、当該指標の効率性計測に当たっての有用性を検証する。また、配分効率性についても、その変化率に注目して計測する。計測結果より、これらの指標は各部門の実態をおおよそ反映したものであることが示された。今後効率性向上施策の成果を捉えるに際し、これらの指標の活用が期待される。また、過去15年間の計測期間においては、施設の無人化等を背景としたネットワーク部門の効率性向上が見られた一方で、一般管理部門の効率性改善率が低く、当該部門における効率性改善の余地が示された。

概要 （英文）

Since Japanese electric power industry is now being deregulated, electric utilities are gradually exposed to competition. In a competitive environment, utilities are required to improve their management efficiency more than before. Therefore, it becomes more important for them to measure their performance and to improve it. To measure their performance, however, the productivity index usually used does not take account of inefficiency of each observation, and the efficiency index measured for each period by Data Envelopment Analysis (DEA) has a limit to be applied to intertemporal efficiency analysis. Considering these problems, this paper applied Malmquist index, which can measure technical inefficiency of each observation and be applied to intertemporal analysis, in order to measure the efficiency trend of Japanese electric utilities between 1983 and 1997. In this study, each utility was separated into 3 sectors, generation, network and administration, and then Malmquist index, which includes technical efficiency change and technical progress, and allocative efficiency index were calculated based on the growth rate respectively for each sector. Furthermore, regression analysis was applied to verify what influenced on these efficiency scores. The results of calculation showed that 1) calculated Malmquist index and allocative efficiency index reflected actual trend of performance in each sector, implying that these indices are useful to measure companies’ performance, 2) the performance of network sector improved most for the observed period, which could be caused by unmanned network facilities and decreasing investments, 3) performance of administration sector showed least progress, which could be caused by large growth of investment and employees during observed period, 4) generation sector’s performance was mainly based on the trend of technical efficiency change, not technical progress, 5) allocative efficiency index improved only for generation sector, which could be caused by the decline of the fuel price in 1986, and 6) most of efficiency scores were influenced by the technical factors such as capacity utilization, fuel efficiency and transmission loss.

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