Techno-economic assessment of hybrid PV/diesel/battery hybrid power systems based on actual performance in Thailand’s national parks

This paper provides a techno-economic analysis of six hybrid PV–diesel–battery systems implemented in remote ranger stations across Thailand’s national parks and wildlife sanctuaries. These systems were designed to replace or reduce diesel-only generation, combining PV arrays of 4.5–25 kWp, battery storage of 20–240 kWh, and diesel generators of 10–48 kW. Modular mounting structures and corrosion-resistant components were used for coastal sites, and all systems were monitored using SCADA and RS485-linked loggers to ensure continuous tracking of operational performance and fuel consumption. Twelve months of operating data formed the basis for a 20-year economic projection, calculating levelized cost of energy (LCOE), net present cost (NPC), and payback periods using actual field performance as the foundation for all assumptions.

The technical assessment found that the off-grid PV/diesel/battery hybrid systems delivered reliable performance under real operating conditions, as shown in Table 1. Data were analyzed according to IEC 61724 standards to derive normalized performance parameters. The annual performance ratio (PR) averaged 72%, with monthly values ranging from 66% during the monsoon season to 78% in the dry season, while final yields (Yf) ranged from 2.9 to 3.4 h/day. Lower PR values were largely caused by PV curtailment when batteries reached a high state of charge, forcing inverters to throttle output an off-grid limitation that contrasts sharply with on-grid systems capable of feeding surplus electricity back to the grid. Capture losses averaged 1.0–1.3 h/day, and system losses were 0.09–0.15 h/day, reflecting the unique operational constraints of isolated hybrid power systems. The economic analysis showed that hybridization provided significant cost advantages. Levelized cost of energy (LCOE) ranged from 0.37 to 0.41 USD/kWh, markedly lower than diesel-only generation (0.90 USD/kWh), while the net present cost (NPC) averaged 65,000 USD per site with a simple payback of 5–7 years. Lower PR values (66–78%) from the performance study slightly increased LCOE by about 0.02 USD/kWh compared to a grid-tied system, yet hybrid operation still displaced over 31,000 liters of diesel annually and avoided approximately 84 tons of CO₂ emissions.

Table 1 provides a consolidated economic summary for each installation site, detailing capital investment, NPC, LCOE, and payback period, offering clear evidence of the systems’ financial viability. Together, these visuals confirm the strong technical reliability and economic competitiveness of hybrid PV/diesel/battery hybrid systems and underscore their potential as scalable models for replication in other national parks and remote conservation areas across Thailand. The proven performance and cost savings provide a compelling framework for wider adoption, supporting the transition toward sustainable, low-carbon electrification in the country’s most isolated regions. This research was financially supported by the Energy Regulatory Commission of Thailand (ERC) under the Section 97(4).