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To protect against market volatility, one powerful tool used across financial markets — and increasingly in BESS — is the Swap Contract.

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The Structure of a Swap

A swap contract is an agreement between two parties to exchange future payment streams. The two components are:
  • The floating leg: A payment stream whose value is volatile and unpredictable — tied to a fluctuating market price, such as real-time electricity prices or variable ancillary services revenues. For a BESS, this is the dynamic income generated by operating the asset in live markets.
  • The fixed leg: A payment stream that is contractually defined at a set, predetermined price that does not change regardless of how the underlying market performs.

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Who Swaps What, and Why?

Swap contracts work because the two parties have opposing risk preferences:
  • Selling volatility: A BESS asset owner who is overexposed to volatile market risk and needs stable revenue to cover fixed costs is willing to receive a fixed sum in exchange for offloading the unpredictable market upside (and downside) onto a counterparty.
  • Buying volatility: A counterparty who is underexposed to market risk — or believes they can generate higher returns through active trading — agrees to pay a fixed sum in exchange for receiving the floating market revenues.

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Swaps Are a Risk Tool, Not a Revenue Enhancer

Swap contracts do not create new money. They simply exchange pre-existing revenue streams between two parties. An asset owner entering a swap should generally expect to give up some upside compared to what they might earn through full market exposure at peak conditions.
The reason asset owners are willing to accept this is straightforward:
  • Certainty over maximisation: They are exchanging potentially large but uncertain revenues for less money in total — but in a fixed, reliable, and bankable format.
  • Facilitating debt financing: Predictable revenue is far more attractive to lenders than volatile market returns. A swap can be the difference between a project being financeable and not.
  • Covering fixed costs: Swap contracts allow asset owners to reliably cover their fixed obligations — debt repayments, O&M contracts, lease agreements — without constant anxiety about market fluctuations.
  • Enabling portfolio growth: By de-risking one project’s cash flow, asset owners can more confidently invest in additional BESS projects, growing their portfolio in a way that full market exposure would make too risky.
There are numerous benefits to exchanging a floating leg for a fixed leg — reliability, bankability, and better long-term financial planning — but additional income is not one of them. Swaps are about optimising the risk profile of existing revenue, not increasing it.
Last modified on April 20, 2026