Energy arbitrage is a key activity in privately-owned energy storage system portfolios. However, the profitability of battery energy storage systems in this domain is limited by two primary challenges: the high cost of battery manufacturing and the insufficient temporal volatility of electricity prices within individual bidding area.

In this context, this study explores the economic viability of relocating the utility-scale battery energy storage systems. To enhance profitability, the proposed portable energy storage system integrates a semi-empirical battery degradation model to accurately account for degradation costs, while its mobility
allows for travel between different bidding zones to exploit inter-zonal electricity price differences.

A mixed-integer linear programming model is built to optimize the system’s daily charging/discharging and transportation scheduling. The system’s daily operations within the Norwegian day-ahead market are simulated using a Python model.

The investigation includes comparative analyses to assess how battery location, chemistry, and degradation models influence system profitability. The study compares stationary and portable battery energy storage systems: in the stationary case, it evaluates profitability with different battery chemistries (lithium ferrophosphate and lithium manganese) in different locations, while the portable case explores the impact of different battery chemistries and degradation models (semi-empirical vs. conventional energy throughput).

The findings reveal that none of the stationary energy storage systems can achieve break-even through conventional temporal arbitrage in the Norwegian day-ahead market. In contrast, relocating the battery proves profitable for all four portable energy storage systems.

Additionally, the application of the depth-of-discharge-aware semi-empirical model enhances profitability of portable systems with both battery chemistries, with the lithium manganese system showing a more than 15% increase in investment return rate. This makes lithium manganese a more attractive option than the lithium ferrophosphate battery due to its lower investment cost, shorter payback period, and higher return on investment.