Fungibility

The property of being interchangeable — where individual units of a good or asset are essentially indistinguishable from one another.

From Latin 'fungi' (to perform, take the place of). In economics and law, fungible goods (oil, currency, grain) can be substituted unit-for-unit.

"The fungibility of climate finance flows means that funding earmarked for African renewable generation often substitutes — rather than supplements — domestic budgets for grid infrastructure."