報告書番号

U91058

タイトル（和文）

ＣＡＥＳ－Ｇ／Ｔ発電のための硬岩地下空洞の圧縮空気貯蔵機能評価－ボーリング孔内での水封機能の実証－

タイトル（英文）

AIR TIGHTNESS OF HARD ROCK FOR COMPRESSED-AIR ENERGY STORAGE -AIR TIGHTNESS TEST IN DEEPLY DRILLED HOLE-

概要 （図表や脚注は「報告書全文」に掲載しております）

岩盤内空洞に貯蔵した気体の漏洩を地下水の作用を利用して防止する方式，すなわち，水封方式は，圧縮空気貯蔵ガスタービン発電システムの経済性向上の有利と考えられる。ただし，わが国における水封方式のこれまでの実績は，燃料地下貯蔵を対象とする数気圧までにとどまり，圧縮空気貯蔵（ＣＡＥＳ）を実用化するためには，数十気圧に対しても水封方式が有効であることを確認する必要がある。そこで，本研究では，孔径１５０ｍｍのボーリング孔内で４００ｍの深さまで貯蔵試験が可能な，孔内水封機能試験装置を製作し，これを用いて水封試験として漏気開始圧試験を行った。これより，硬岩の水封機能として，地下水の作用により漏気を生じさせないで貯蔵できる圧力，すなわち漏気開始圧を求め，漏気開始圧はほぼ初期間隙水圧かあるいはそれ以上となることを明らかにした。

概要 （英文）

COMPRESSED-AIR ENERGY STORAGE WITH GAS-TURBINE GENERATORS (CAES-G/T) IS CONSIDERED AN EFFICIENT WAY TO STORE LARGE AMOUNTS OF ENERGY FOR ELECTRICITY LOAD LEVELLING. THE FEASIBILITY OF CAES-G/T DEPENDS ON WHETHER AIR RESEVOIRS CAN BE CONSTRUCTED ECONOMICALLY. SINCE JAPAN HAS NO SALT DOMES LIKE THOSE FOUND IN GERMANY OR THE USA,THE BEST CHOICE MAY BE SITES WITH ABUNDANT GROUND WATER TO STORE COMPRESSED AIR IN UNLINED SUBMERGED HARD-ROCK CAVERNS USING THE SURROUNDING GROUNDWATER PRESSURE HEAD. THE AIR TIGHTNESS DESIGN OF ROCK CAVERNS USING GROUND WATER IS NOT FULLY ACCEPTED IN JAPAN. SECURING AIR TIGHTNESS USING GROUND WATER HAS PROVED EFFECTIVE FOR FUEL STORAGE,BUT THE STORAGEPRESSURE IS ONLY 2 TO 10 ATM,WHICH IS LOWER THAN THE PRESSURE OF 40 TO60 ATM USED FOR CAES. IN THIS CONTEXT,FIELD WORK HAS BEEN CARRIED OUT TO EXAMINE THE AIR TIGHTNESS OF A ROCK MASS USING SPECIALLY-DESIGNED TEST APPARATUS IN A DEEPLY-DRILLED HOLE. SOME OF THE RESULTS ARE AS FOLLOWS: (1) AN AIR TIGHTNESS TEST APPARATUS HAS BEEN DEVELOPED TO EXAMINE THE AIR TIGHTNESS IN A DEEPLY-DRILLED HOLE. IT CAN BE INSTALLED AT 400 METERS IN A DRILLED HOLE WITH A DIAMETER OF 150 MM. THE TEST PRESSURE CAN BE INCREASED TO MORE THAN 40 KGF/CM2. (2) THE TEST-SITE ROCK IS COMPOSED OF CM GRANODIORITE IN TERMS OF CRIEPI S ROCK CLASSIFICATION WITH A 60 TO 70-M WEATHERED LAYER ON TOP. THE PERMEABILITY OF THE ROCK VARIES FROM DEPTH-TO-DEPTH WITH VALUES OF 10**-4 TO 10**-7 CM/S. THE IN-SITU PORE WATER PRESSURE IS DISTRIBUTED ALMOST HYDROSTATICALLY TO A DEPTH OF 400 METERS. (3) THE AIR TIGHT PRESSURES WERE MEASURED BY THE TEST APPARATUS AND WERE CONFIRMED TO BE ALMOST EQUAL TO OR GREATER THAN THE PORE WATER PRESSURE AT EACH DEPTH.

報告者

キーワード