Sustainable Marine Structures

Multi-Criteria Site Suitability Assessment for Nearshore Floating Solar Photovoltaic Systems in the Gulf of Thailand: Integrating Hydrodynamic, Economic, and Environmental Factors

Kornpaphop Ruttanawijit

Department of Energy Technology, Faculty of Engineering and Industry Technology, Rambhai Barni Rajabhat University, Chanthaburi 22000, Thailand

Taweesup Desua

Department of Energy Technology, Faculty of Engineering and Industry Technology, Rambhai Barni Rajabhat University, Chanthaburi 22000, Thailand

Yodchai Tiaple

Department of Maritime Engineering, Faculty of International Maritime Studies, Kasetsart University, Sriracha Campus, Chonburi 20230, Thailand

DOI: https://doi.org/10.36956/sms.v8i2.3210

Received: 20 March 2026 | Revised: 6 April 2026 | Accepted: 15 April 2026 | Published: 7 May 2026

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Abstract

The paper provides a macro-level screening procedure for nearshore floating photovoltaic (N-FPV) suitability using province-level analysis based on Analytic Hierarchy Process (AHP)-Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) multi-criteria decision making supported by entropy objective weighting validation. The study assesses nine coastal provinces based on the following factors: irradiance, wave height, wind velocity, tidal range, coastal erosion, current velocity, proximity to existing grids, and industrial demand utilizing ERA5 reanalysis data (2019–2023) validated by 31 in-situ stations in the region. The inter-factor independence is confirmed with Pearson correlation analysis (|r| < 0.70 for all pairings), and asymmetric wind factor penalties are introduced to improve the physical realism of the ranking. Rayong (Ci = 0.741) and Chonburi (Ci = 0.682) are selected as tier 1 regions because of their high irradiance levels (5.15–5.29 kWh/m²/day), moderate waves (Hs = 0.48–0.52 m), and high-quality industrial infrastructure along the Eastern Economic Corridor. The results are further validated with ViseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) cross-checking, entropy weighting, demand proxy analysis, and criteria structure modification. The proposed approach shows strong stability to weight perturbations of up to ±22%. A techno-economic analysis of a 10 MWp system results in a range of Levelized Cost of Electricity (LCOE) values between $0.096–$0.111/kWh (Monte Carlo 50th percentile (P50): $0.097–$0.112/kWh). The scale analysis reveals a 12–18% reduction in costs per kilowatt of output at 5–50 MWp capacity levels. Project feasibility relies heavily on corporate power purchase agreements at or above $0.12/kWh; currently, the feed-in tariff is at $0.08/kWh, which leads to negative returns. Carbon credits can provide additional income. The results can be interpreted as provincial tiers before the actual screening of site locations; Geographic Information System (GIS) exclusion mapping and extreme-event studies should be considered mandatory.

Keywords: AHP-TOPSIS; Province-Level Pre-Screening; Eastern Economic Corridor; Levelized Cost of Electricity; Corporate Power Purchase Agreement; Marine Renewable Energy

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