The clause that carries decades
Long-dated offtake contracts fix a price today for a service delivered over decades. Indexation is how that price moves. Get it right and the revenue tracks the cost base; get it wrong and a margin erodes quietly for twenty years.
What the mechanism should track
The principle is that indexation should follow the costs it is meant to cover. In practice that means splitting the payment and indexing each part differently:
- Fixed capital recovery is generally not indexed, or only partly — the debt it services is fixed
- Operating and maintenance tracks a cost index relevant to the actual expense base, including labour
- Fuel or input costs, where the project bears them, follow their own pass-through rather than a general index
A single blended index applied to the whole payment is simpler to draft and almost always wrong for one component or another.
The currency question
Where costs are incurred partly in a currency other than the payment currency — imported spares, expatriate labour, foreign-denominated service contracts — indexation to a domestic index alone leaves an exposure. Most Gulf currencies are pegged to the dollar, which removes much of this concern, but not where costs arise in euros, yen, or sterling.
Fallbacks that are usually missing
The index ceases to be published. Statistical agencies revise, rebase, and discontinue series. A clause naming an index without a mechanism for its replacement leaves the parties negotiating under pressure.
The index is rebased. Continuity of the series matters more than the absolute value; a rebasing without a linking provision can produce a step change nobody intended.
Publication is delayed. What is used if the figure is not available at the payment date, and how is any adjustment reconciled afterwards.
A short checklist
- Split the payment and index each component to its own cost driver
- Check whether costs arise in a currency the index does not reflect
- Include a replacement mechanism for discontinuation and rebasing
- State what happens if publication is late
- Model the mechanism across a long horizon, including a period of high inflation, before agreeing it
Indexation is one of the few contract terms that compounds. A small error is invisible at signing and material by year fifteen.
