Cost-Optimised Design of Hybrid Solar–Wind–Battery Power Systems for Autonomous Communication Towers in Latvia

The study presents a computational framework for optimising hybrid solar–wind–battery power systems for autonomous communication towers under Latvian climatic conditions. A Python-based model, incorporating pvlib, windpowerlib, and meteorological datasets (ERA5, NEWA), is used to simulate hourly energy generation, battery state of charge, and system costs across a three-dimensional parameter space of solar capacity, wind capacity, and battery storage. The primary objective is to identify the least-cost configurations that ensure at least 99 % tower uptime. Detailed results are demonstrated for one specific communication tower site in Latvia, where pronounced non-linear behaviour is observed between equipment cost and achievable uptime: initial investments yield rapid reliability gains, while approaching 99 % uptime requires disproportionately higher costs due to rare but prolonged energy deficit periods. For the built experimental reference tower, the globally optimal configuration achieving 99 % uptime includes approximately 36.7 kW of solar PV, 5.9 kW of wind, and 54 kWh of battery storage at a total cost of €45,000, while additional constrained scenarios with fixed existing solar or wind capacity are also evaluated. The results highlight the need for balanced scaling of all three components and provide spatially interpolated maps of optimal system parameters at over 10,000 points, supporting technically and financially sound design of off-grid communication tower solutions in Latvia.