Inventory transition
I_(t+1) = I_t + q_tToday's action changes the inventory available for future decisions.
Power & Commodities
Gas Storage Optionality
Gas storage assets embed an option to shift volume across time, constrained by capacity and injection/withdrawal limits.
Mental model
Stored gas is a sequence of constrained choices to move volume from low-value dates to higher-value dates.
Storage allows injecting gas when prices are low and withdrawing when prices are high, subject to operational limits.
The value of storage depends on term-structure shape, volatility of spreads, and correlations across maturities.
Explore the mechanism
When should inventory be injected, held, or withdrawn after prices and physical constraints are considered?
This diagram shows a gas forward curve, a simple storage policy, and the resulting inventory path. The policy injects when prices are low and withdraws when prices are high; the value is the net spread captured.
Approx. strategy value ≈ -2358 € (per unit of capacity-scale)Max storage level ≈ 75.0 / 100.0 (75% utilised)
Numbers
Total injections ≈ 75.0 units
Total withdrawals ≈ 0.0 units
Strategy value ≈ -2358 €
Interpretation
Storage optionality is the right, not the obligation, to buy in low-price periods and sell in high-price periods within capacity and rate constraints. The triggers here implement a simple heuristic strategy.
The economic value comes from the shape and volatility of the forward curve and from how much inventory and flexibility you have. Real valuation solves a dynamic optimisation problem; this picture keeps the mental model of shifting volume across time to harvest spreads.
UNDERSTAND
What to notice
Pricing and hedging gas storage requires dynamic optimisation, not just static valuation of individual forwards.
The quantitative structure
Notation
I_t- inventory at time t
q_t- signed injection or withdrawal decision
K- storage capacity
Capacity constraint
0 <= I_t <= KEvery exercise policy must remain within physical storage bounds.
This model assumes
- Operational constraints and fees are represented at the decision frequency.
- The price dynamics and terminal inventory treatment match the valuation purpose.
A small example
Use now or preserve inventory
Inventory is 50 units. The facility can withdraw 10 today. Today's net sale margin is 3 per unit; the expected next-period margin is 6.
- Withdrawing today earns 10 * 3 = 30.
- Preserving the 10 units retains a possible next-period margin of 10 * 6 = 60.
- Ignoring uncertainty and other constraints, waiting has 30 more continuation value.
ResultThe example shows why the highest current positive spread need not be the optimal exercise time.
Where it appears
- seasonal gas balancing
- optimizing storage dispatch
- hedging time-spread exposure
Where the intuition breaks
What this view leaves out
- Intrinsic spread value can miss volatility value, but stochastic models can still misstate operational outages, ratchets, fees, and market liquidity.
Common mistakes
“Storage value is just the current winter-minus-summer spread.”
Not quite.Storage is a sequence of constrained future choices, so volatility and the ability to revise decisions create additional value.
Where this concept sits
Follow the strongest prerequisites, applications, extensions, and contrasts.
Connections for Gas Storage Optionality
Gas Storage OptionalityYOU ARE HERE
Built onEconomic OptionalityGas storage is valuable because inventory and injection decisions preserve choices across future price states.
UsesForwards and Futures Pricing (Cost of Carry)Storage value is driven by the ability to move inventory across time in response to forward and spot price spreads.
Related toSwing Options and Volume FlexibilityBoth are multi-exercise commodity optionality problems with intertemporal constraints and state-dependent decisions.
ExtendsOption Payoff Types and Path DependenceStorage is a real option whose value depends on a sequence of inventory and price decisions rather than a single terminal payoff.
Related toOptimal Execution as Stochastic ControlBoth problems choose actions through time under uncertainty subject to state constraints and trading or physical costs.
Built on · Economic Optionality
Gas storage is valuable because inventory and injection decisions preserve choices across future price states.
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