The "Stocks Relative to Heating Season Demand" ratios are calculated for each year as the proportion of working gas storage as of the end of October relative to consumption for the period November through March.

• As stocks have declined relative to consumption, the resulting change in the market role of storage has resulted in greater price volatility. Lower initial stock volumes when used intensely, especially early in the winter, require replenishment or supplies may become scarce later – for example, the winter of 1995/96 saw persistent low temperatures that did not allow stock replacement as intended, resulting in high prices late in the winter.

• Lower storage volumes have not compromised supply security, but the markets rely increasingly on prices signals to allocate available supplies to consumers.

• These trends show the pivotal role of storage gas as a buffer supply to balance demand and supply shifts.

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