Banking

Banking allows firms to save surplus allowances or carbon credits earned in one compliance period and use them in a future period. It is one of the key design features that determines how flexible — and how efficient — an ETS is.

Why banking improves efficiency

Without banking, unused allowances expire worthless at the end of each period. This creates perverse incentives: firms race to use or sell allowances before the deadline, often causing a price crash at period end. Banking smooths out this behaviour by giving surplus allowances a persistent value.

Banking also lowers the total cost of meeting a long-run emissions pathway. Firms can over-abate cheaply today and bank the credits for an expensive period later — or simply smooth out year-to-year variation in their emissions.

Multi-year banking vs. one-cycle banking

• Multi-year banking: credits bank across all periods indefinitely. This gives firms maximum flexibility and is the standard in the EU ETS.
• One-cycle banking (India CCTS default): credits can only be carried forward into the next period, not beyond. This limits speculative hoarding and keeps each period's market relatively self-contained — important when the regulator is still learning how to calibrate the scheme.

Borrowing

The opposite of banking — using next period's allowances early — is called borrowing. Most schemes prohibit it outright, since it undermines the environmental integrity of the current period's cap.

In the simulator

When banking is enabled you can carry surplus credits into future periods. Toggle between multi-year and one-cycle banking to see how it affects strategy and end-of-period prices.