Integrating life cycle assessment and costing in organic rice systems: scenario-based evaluation of water management and clean energy strategies in Thailand

This study evaluates the environmental and economic performance of organic rice production in northern Thailand by integrating life cycle assessment (LCA) and life cycle costing (LCC). The objective was to determine whether alternate wetting and drying (AWD) and solar pump irrigation (SPI) enhance sustainability in smallholder organic systems. A cradle-to-farm gate boundary was applied with a functional unit of 1 kg paddy rice. Three mitigation scenarios were compared with the baseline: AWD (Sc1), SPI (Sc2), and an integrated AWD–SPI system (Sc-Integrated). Primary data were collected from certified farms in Uttaradit Province, while background processes were modeled using Ecoinvent v3.8 and Thai databases. Environmental impacts were assessed using ReCiPe 2016, and GHG emissions were estimated using IPCC Tier 1 methods adapted to Thai conditions. The LCC was conducted over a 10-year horizon with a 5% discount rate. Field methane emissions dominated the baseline footprint (1.16 kg CO2 eq/kg-rice). Relative to baseline, Sc1 reduced GHG emissions by 23% and LCC by 27%, Sc2 by 8% and 59%, and Sc-Integrated by 31% and 61%. Sc2 delivered the highest benefit–cost ratio (1.53) and internal rate of return (20%), while Sc-Integrated achieved the more balanced environmental and economic gains. AWD and SPI are complementary climate-smart practices. Their integration maximizes environmental benefits and cost savings, while the combined LCA–LCC framework provides a replicable tool to guide sustainable rice production and green economy transitions.