報告書番号

U02050

タイトル（和文）

水封式圧縮空気貯蔵の実証 --横坑での気密試験--

タイトル（英文）

Experimental study on water confining of high-pressure air in an unlined underground cavern - Air leakage test with a lateral cavern -

概要 （図表や脚注は「報告書全文」に掲載しております）

将来の電力貯蔵技術として有望視される圧縮空気貯蔵ガスタービン発電システム(CAES)を我が国で実用化しようとする場合、圧縮空気貯槽の経済的な建設が必要となる。これに応える技術として地下貯槽空洞の壁面を無覆工としたまま、周囲の地下水により気密性を確保する方式、いわゆる水封方式による高圧の圧縮空気地下貯蔵を提案してきた。本報告は、この水封機能を実際の貯槽形式となる横坑においても確保可能であることを実証するために、現地で実施した実証実験結果について述べるものである。現場は神岡鉱山内にあり、片麻岩を主に構成された岩盤を対象とした。水没していた旧坑道に新しく掘削した横坑(3.2m x 3.2m x 51m)をプラグで閉塞した無覆工の貯槽空洞に、地上より高圧空気を給気して貯蔵実験を行った。貯蔵圧力と漏洩量の関係を繰り返し求め、水封式圧縮空気貯蔵技術を実証した。

概要 （英文）

Electric power consumption in Japan has a trend to concentrate early in the afternoon. Especially in summer the peak of the consumption often becomes more than double of the lowest. So electric energy storage is a major issue of Japanese power suppliers. In addition to pumped hydro power stations, middle-sized storage systems are required for efficiency these days. From this point a compressed air energy storage (abbreviated as CAES) system has been studied recently as an effective option. In this system, during the low consumption time, we drive a compressor and store highly compressed air into storage caverns. In daytime we retrieve and use the stored compressed air for power generation. Foregoing CAES systems in Germany and the U.S. have the storage caverns constructed in salt dome. As unfortunately we don't have such salt dome in Japan, a large amount of highly compressed air should be stored in deep excavated caverns without lining in order to make the CAES system more economical and more feasible in Japan. In this case, the air leakage would be prevented by surrounding underground water (this can be called as "water confining system"). In a series of investigations of the water confining system the air tightness of submerged rock had been confirmed in boreholes in fields. As the last stage of the series of investigation, an empirical study in a field was carried out recently.The test site is located in Kamioka Mine, Gifu Prefecture, Japan. It mainly consists of Paleozoic gneiss. In the test site we had an abandoned investigation gallery at the lowest level. A test chamber (3.2m x 3.2m x 51m) was excavated and left without lining at the end of the existing gallery. The difference in height between the test chamber and the entrance of the gallery was nearly 200m. The test chamber was submerged in the depth of water up to the entrance of the existed gallery. After that compressed air was injected into the test chamber and the pressure of the compressed air was raised up to the pressure equivalent with or more than the pressure of surrounding water pressure. With this empirical study, the feasibility of compressed air storage with the water confining system was demonstrated as well as related fundamental geohydrological characteristics were surveyed.

報告者

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