Energy bank peakshaving gas helps keep Chicago warm

The problem in supplying Chicago's 900,000 customers with gas energy year-round lies in predicting when the winter's subzero cold waves will hit and how long they will last. Peoples Gas's underground aquifer-type storage reservoirs resolve that problem by serving as an energy bank - receiving gas deposits in the summer and sending out 20-30 billion CF of withdrawals in the winter. On very cold days, the percentage of peak demand met by storage gas can reach 68.5%. The Manlove storage field in central Illinois, which lies under 23,000 acres of fertile farmland, can supply up to 800 million CF/day out of its 45 billion CF inventory. (An aboveground LNG facility adds another 300 million CF/day from its 2 billion CF storage capacity). Manlove's 137 injection and withdrawal wells reach 4000 ft down into the Mt. Simon sandstone layers that hold the gas. The storage complex has been under development since 1959.