Floatovoltaics is rapidly emerging as a novel type of sustainable energy technology, in which solar photovoltaic installations are sited directly on open-water spaces. As an agro-renewable energy-generation technology, it makes dual use of water to generate revenue from under-utilised irrigation water surfaces while also offering mutually beneficial layers of land-saving, environmental conservation and water-preservation benefits. Standardised metrics for ground-mounted photovoltaic projects, however, do not properly account for the technology’s extended range of resource-use-efficiencies and impact-effect-positives. Such knowledge gaps hinder evidence-based scientific assessments in regulatory project permissions mandated by law. Technology planning and impact assessment practices can benefit from a computer-aided technique to characterise floatovoltaic performance profiles. This paper introduces a conceptual empirical modelling framework, a holistic system dynamics-thinking methodology and a computer synthesis model to empirically predict the performance and sustainability profiles of prospective floatovoltaic installations. By inherently exploring the techno-economic and techno-environmental externalities of floatovoltaic enterprises, it translates performance profiles into sustainability indicators, articulated as WELF-nexus parameters. The paper details the integrated analytical framework, mathematical modelling formulation and digital computer synthesis model towards quantitative floatovoltaic energy system planning and sustainability assessments. The study’s main finding is that an integrated techno-enviro-economic floatovoltaic assessment methodology can be successfully modelled as a context-sensitive synthesis technique in a system dynamics modelling environment. The proposed technique can find utility in solving real-world problems with assessments in efficiency, feasibility and sustainability for agricultural floatovoltaics.