Offshore wind is expected to become the largest energy source in the Netherlands. However, its economic viability has come under increasing pressure. Integrating energy storage with wind generation offers a potential solution by enhancing system flexibility and enabling additional revenues through multi-market participation. Hybrid Power Plants (HPPs) combine generation and storage technologies within a single system. This study investigates how the integration of short- and long-duration energy storage affects the profitability of wind-based HPPs operating across multiple electricity markets.
Short-duration lithium-ion (Li-ion) battery storage was compared with long-duration Liquid Piston Compressed Air Energy Storage (LPCAES). Lithium-ion batteries were evaluated while explicitly accounting for degradation, whereas LPCAES represents an emerging near-isothermal CAES technology with improved compression efficiency. Both technologies are evaluated across different energy capacities and charge/discharge rates within a multi-market framework, including participation in the day-ahead and automatic Frequency Restoration Reserve (aFRR) markets. Profitability is assessed using operational revenues and a Net Present Value analysis.
Results show that economic performance strongly depends on market conditions, storage sizing, degradation effects, and investment assumptions. Without degradation, Li-ion batteries generally outperform LPCAES in terms of profit due to higher efficiency and power capability. When degradation is considered, outcomes become year-dependent: LPCAES can achieve higher profitability under moderate price conditions and larger storage sizes, whereas Li-ion remains superior in high-price years. Overall, no single technology is universally optimal; the economically preferred option depends on the specific market environment and system configuration.