Plant factories with artificial lighting (PFALs) provide year-round production, controllable environments, consistent product quality, and high space-use efficiency, positioning them as an important form of controlled-environment agriculture (CEA) moving toward intensification and digitalization. However, their commercialization has been constrained by high capital investment, electricity dependence, labor and operation-and-maintenance costs, and insufficient realization of market value. Existing studies have typically examined crop yield, light-environment control, energy use, capital cost, or market price in isolation, with limited integration of crop production, control maturity, energy conditions, and market realization into a computable framework. The aim is to identify the profitability boundary of PFAL lettuce, clarify how control maturity affects marketable yield, unit electricity use, labor substitution, annualized capital cost, and unit cost, and identify feasible transition pathways.

A production-side accounting boundary was adopted. Annualized capital cost, maintenance cost, electricity cost, labor cost, nutrient solution and seed costs, and other operating costs were included, whereas cold-chain logistics, retail terminal costs, brand advertising costs, financing costs, and complete channel-organization costs were excluded. Three levels of control maturity, three energy scenarios, and three market scenarios were specified, resulting in 27 deterministic scenarios. The model was constructed following the logic of "scenario input–control mapping–cost–benefit calculation–profitability boundary identification–vulnerability diagnosis". Control maturity was incorporated into the profit function through gross yield, marketable rate, unit electricity consumption per unit of marketable product, labor-substitution coefficient, and unit capital expenditure (CAPEX). An economic vulnerability index (EVI), consisting of profit gap, energy exposure, and carbon-constraint exposure, was further constructed. Local elasticity analysis, weight-robustness tests, and extended scenarios involving policy support and channel costs were used to examine the explanatory boundary of the results.

The economic feasibility of PFAL lettuce exhibited a distinct "narrow-window" characteristic. Among the 27 deterministic scenarios, only 5 achieved positive profit, accounting for 18.5%, and all were concentrated in the high-value direct-supply market. Under the benchmark scenario of "conventional grid electricity + high-value direct-supply market", upgrading control maturity from basic control to closed-loop intelligent control increased marketable yield from 70.40 to 109.25kg/(m²·year), reduced unit electricity consumption from 12.0 to 8.4kWh/kg, decreased unit cost from 27.67 to 19.26 CNY/kg, and increased profit from -258.36 to 518.04CNY/(m²·year). Cost decomposition showed that although control upgrading increased annualized capital cost per unit area, higher output diluted capital cost per unit product. Meanwhile, improved labor substitution and reduced unit electricity consumption lowered labor cost and electricity cost, respectively. Break-even analysis indicated that higher control maturity flattened the break-even boundary between selling price and electricity price, reflecting lower sensitivity to electricity price fluctuations. The EVI results further showed that profitability ranking and vulnerability ranking were not fully consistent. The best scenario was "closed-loop intelligent control + energy-abundant condition + high-value direct-supply market", with an EVI of 0.088, whereas the worst scenario was "basic control + high-price and high-carbon electricity condition + conventional fresh-food market", with an EVI of 0.727. Local elasticity analysis showed that marketable yield had the largest effect on unit cost, with an elasticity of approximately -0.57, followed by unit CAPEX at approximately 0.49. The elasticities of electricity price and unit electricity consumption were both approximately 0.33. Sensitivity analysis of policy support and channel costs showed that investment subsidies and preferential electricity prices improved the financial performance of some boundary scenarios, whereas additional costs associated with packaging, fulfillment, channel maintenance, and sales organization compressed profit margins in high-value markets.

The feasibility of PFAL lettuce production is not determined by single-factor cost reduction, but by the joint effects of control maturity, energy conditions, market value realization, and channel costs. Conventional fresh-food markets and general premium-brand markets are unlikely to support profitable PFAL lettuce production. Only in high-value direct-supply markets, and when the control level reaches at least the enhanced-control stage, can the system cross the break-even line. The value of control upgrading should not be understood merely as electricity saving, but as a comprehensive mechanism that simultaneously increases marketable yield, improves the marketable rate, reduces unit electricity consumption, enhances labor substitution, and dilutes capital cost. A more robust transition pathway should therefore be built on the synergy among control upgrading, favorable electricity conditions, value-chain upgrading, and policy support. The conclusions of this study are applicable to production-side boundary identification under publicly available data conditions, but should not be directly interpreted as evidence of stable profitability for specific commercial projects.