Long-duration energy storage is increasingly vital for maintaining reliability in electricity systems transitioning toward zero-carbon generation. However, uncertainty in future revenue streams creates a significant barrier to private investment. Policymakers have introduced contractual mechanisms—particularly cap-and-floor schemes—to reduce investor risk, but their true effectiveness remains poorly understood because prior evaluations relied on simplified, externally imposed price assumptions.
Researchers at a leading energy economics group have now developed a more realistic analytical framework. Their two-stage stochastic equilibrium model endogenously captures how contract design, capacity decisions, and financing costs interact. Rather than assuming fixed price distributions, the model allows market outcomes to adjust in response to policy choices, providing a more accurate picture of real-world dynamics.
Applying this framework to a stylized Great Britain system reveals critical insights. Market incompleteness—the inability to hedge all revenue risks—substantially depresses storage investment independent of policy. Zero-premium, centrally administered contracts can restore risk-neutral investment levels by eliminating downside exposure for investors. However, this protection comes at a cost: consumers must absorb substantial expected transfers, and outcomes remain highly sensitive to the specific cap, floor, and risk-sharing parameters chosen.
Bilaterally negotiated contracts present a different trade-off. These arrangements significantly reduce expected consumer transfers and create more robust outcomes across varying parameter assumptions. Yet they provide weaker investment signals, making it harder to achieve targeted deployment levels.
The research underscores that no single contract type optimally balances all objectives. Policymakers must move beyond evaluating contracts in isolation and instead consider how contractual mechanisms interact with broader institutional structures—including market rules, risk management frameworks, and regulatory oversight. A coordinated approach to both contract and institutional design offers the best path forward for mobilizing the storage capacity essential to reliable, decarbonized electricity systems.
